Vapor Recovery Unit PLC
Operation manual
Important Message
READ CAREFULLY BEFORE INSTALLING AND STARTING YOUR VAPOR RECOVERY UNIT (VRU).
The following instructions have been prepared to assist in installation, operation and maintenance of Vilter VRUs.
Following these instructions will result in a long life of the unit with satisfactory operation.
The entire manual should be reviewed before attempting to install, operate, service or repair the VRU.
A Vapor Recovery Unit (VRU) is a positive displacement machine. It is designed to compress gas. The compres-
sor must not be subjected to liquid carry over. Care must be exercised in properly designing and maintaining
the system to prevent conditions that could lead to liquid carry over. Vilter Manufacturing is not responsible
for the system or the controls needed to prevent liquid carry over and as such Vilter Manufacturing cannot
warrant equipment damaged by improperly protected or operating systems.
VRU components are thoroughly inspected at the factory. However, damage can occur in shipment. For this
reason, the equipment should be thoroughly inspected upon arrival. Any damage noted should be reported
immediately to the Transportation Company. This way, an authorized agent can examine the unit, determine
the extent of damage and take necessary steps to rectify the claim with no serious or costly delays. At the
same time, your distributor should be notified of any claims made.
All inquires should include the Vilter sales order number, VRU serial and model number.
All requests for information, services or parts should be directed to your distributor.
Equipment Identification Numbers:
Vilter Order Number: _______________________Compressor Serial Number: _________________
Vilter Order Number: _______________________Compressor Serial Number: _________________
Vilter Order Number: _______________________Compressor Serial Number: _________________
Vilter Order Number: _______________________Compressor Serial Number: _________________
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Table of Contents
Section Title
Section Number
Important Message................................................................................................................................ i
Section 1 • General Information
How To Use This Manual......................................................................................................................... 1-1
Glossary of Terms................................................................................................................................... 1-2
Hardware Components.......................................................................................................................... 1-4
Section 2 • Operational Descriptions
Overview ............................................................................................................................................... 2-1
Section 3 • Overview Screens
Main Menu Screen ................................................................................................................................. 3-1
Main Screen ........................................................................................................................................... 3-2
Compressor Control Screen ................................................................................................................... 3-4
Alarm and Trip Setpoints Screen............................................................................................................. 3-6
Pressure Calibration Screen.................................................................................................................... 3-7
Temperature Calibration Screen............................................................................................................. 3-8
Pressure Control - PID Screen ................................................................................................................. 3-9
Oil Cooling Fan - PID Screen ................................................................................................................... 3-11
Discrete IO Status Screen ....................................................................................................................... 3-13
VFD Status Screen.................................................................................................................................. 3-16
EPA Data Screen..................................................................................................................................... 3-18
EPA Event List Screen.............................................................................................................................. 3-19
Options Screen ...................................................................................................................................... 3-20
Set PLC Date & Time Screen.................................................................................................................... 3-21
Section 4 • HMI Navigation
Alarm Messages..................................................................................................................................... 4-1
Trip Messages ........................................................................................................................................ 4-2
Status Messages .................................................................................................................................... 4-6
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
Blank / TOC
Section 1 • General Information
HOW TO USE THIS MANUAL
This manual contains instructions for the PLC. It has
been divided into 4 sections:
Section 1: General Information
Section 2: Operational Descriptions
Section 3: Overview Screens
Section 4: Alarms, Trips and Status Messages
It is highly recommended that the manual be reviewed
prior to servicing system parts.
Figures and tables are included to illustrate key concepts.
ADDITIONAL IMPORTANT NOTES
• Installation, operation and maintenance instructions
can be found in the associated VRU manual.
• Due to continuing changes and unit updates, always
refer to the Vilter.com website to make sure you have
the latest manual.
• Any suggestions of manual improvements can be
made to Vilter Manufacturing at the contact informa-
tion on page i.
• For Wiring Requirements, refer to your supplied
Electrical Drawings.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 1 • General Information
Glossary of Terms
Alarm Warning
Oil Stabilizer Temperature
Temperature of the gas measured at the oil stabilizer
vessel.
Annunciated by the compressor PLC that an operational
or process condition is abnormal. When active, alarms
will be displayed but will not shut down the compressor.
Outlet Scrubber
Vessel located on the outlet side of gas compressor to
remove moisture, oil, and/or contaminants.
Compressor Differential Calculated
PID Controller
Discharge Pressure minus Suction Pressure. Monitored
to ensure compressor is equalized before starting.
PID stands for “Proportional Integral Derivative.” A PID
controller manipulates a control variable (example: fan/
pump speed) to maintain a process variable (example:
process temperature or pressure) at a desired value (set-
point). The controller is driven by mathematical calcula-
tions that tell the control variable how to react to chang-
es in the process variable.
Differential Pressure
The difference between the Discharge Pressure and
Suction Pressure.
Discharge Pressure
PLC
Pressure of the gas measured at the outlet of the
compressor.
PLC stands for “Programmable Logic Controller.” The
Compressor PLC is an industrial computer that controls
the compressor unit or Package.
Discharge Temperature
Temperature of the gas measured at the outlet of the
compressor.
Pressure Equalizing Solenoid
Solenoid Valve that opens at compressor stop to equal-
ize suction and discharge pressures.
Ethernet IP
Communication protocol used to communicate to the
compressor PLC.
Pressure Ratio
The ratio of compressor discharge pressure to suction
pressure.
HMI
HMI stands for “Human-Machine Interface.” The com-
pressor HMI is a touch screen terminal mounted in the
door of the compressor control enclosure.
Pressure Ratio Calculated
(Discharge Pressure) / (Suction Pressure)
Pressure Transducer or Transmitter
Device that measures pressure and transmits the pres-
sure reading as a 4-20mA signal. This 4-20mA signal is
read by the PLC and displayed as a pressure.
Oil Cooler
Heat Exchanger where hot oil from the compressor is
cooled.
RTD
Oil Cooler Outlet Temperature
RTD stands for “Resistance Temperature Detector.”
RTDs use electrical resistance to measure temperature.
This resistance is read by the PLC and displayed as a
temperature.
Temperature of compressor oil measured at the outlet
of the oil cooler.
Oil Stabilizer Heater
Suction Pressure
Heater element(s) used to heat the oil in the oil stabilizer
vessel.
Pressure of the gas measured at the inlet of the
compressor.
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Section 1 • General Information
Status
Compressor status message to inform an operator what
the VRU is doing while it is running.
Tank Suction Pressure
Pressure of the storage tank as measured at the process
critical location. This is the process control pressure that
the VRU uses to control when it starts and stops as well
as control the Scroll Compressors speed.
Temperature Transmitter
Device that measures temperature and transmits the
temperature reading as a 4-20mA signal. This 4-20mA
signal is read by the PLC and displayed as a temperature.
Trip
Compressor shutdown due to an abnormal process or
operational condition.
VFD
VFD stands for “Variable Frequency Drive.” A VFD is a
motor control device that can vary the speed of an AC
induction motor.
VFD Current
The measure of current (in Amperage) from each VFD.
VRU
Vapor Recovery Unit
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Section 1 • General Information
Hardware Components - PLC Exterior
Each Compact Logix PLC may differ, but below are typical components that can found in each PLC. For specific PLC
layout, refer to supplied electrical drawings.
1 - Enclosure Door
2 - Main Enclosure
3 - Door Latch
4 - HMI
5 - Master Power
6 - Compressor Control Reset Button
7 - Emergency Stop Button
1
2
3
4
5
6
7
3
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Section 1 • General Information
Hardware Components - Enclosure Door Interior
1
4
2
5
6
7
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Section 1 • General Information
Hardware Components - Main Enclosure Interior
8 - Ethernet Switch, 5 Port RJ45
13 - Relays
9 - DC Power Supply
14 - Terminal Blocks
15 - Fuses
10 - Compact Logix Processor
11 - Compact Logix 4 Input Current Analog Module
DC Power Supplies
16 - DC Power Supply
17 - Panel Heater (Field Installed)
12 - Compact Logix 2 Channel RTD Module
8
9
10, 11, 12
17
16
15
14
13
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Section 2 • Operational Descriptions
AUTO START-STOP
Overview
When enabled, the Auto Start-Stop feature will allow
the VRU to cycle on and off based on the Tank Suction
Pressure. Additional variables that factor in to Auto
Start-Stop are described below:
The following are standard equipment on all Vapor
Recovery Units that can be controlled or monitored:
• Compressor Start Pressure: The Tank Suction Pressure
which will control the start of the compressor.
• Pressure
• Suction Pressure – Pressure of the gas measured
at the inlet of the compressor.
• Initial Runtime before VFD A7B Increases from
Minimum Speed: Amount of time that the Scroll
Compressors will run at the minimum speed (50%)
before being controlled by the PLC’s PID.
• Discharge Pressure – Pressure of the gas at the outlet
of the compressor. Measured at the oil separator.
• Compressor Stop Pressure: The Tank Suction Pressure
which will control the stop of the compressor.
• Tank Suction Pressure – Pressure of the gas at the
controlled point in the system.
• Minimum Stabilizer Oil Temperature: The Stabilizer
Oil Temperature must be at a minimum 180°F before
the compressors are allow to run.
• Temperature
• Stabilizer Oil Temperature – Temperature of the
Oil in the Stabilizer.
• Oil Cooler Outlet – Temperature of the Oil coming
out of the Oil Cooler.
When Auto Start-Stop control is enabled, it will function
as follows:
• Discharge Outlet Temperature – Temperature
of the gas and oil mixture at the outlet of the
compressor
1. Pressing the “Unit Start” Push-Button (push-but-
ton) on the HMI Main Screen will place the VRU in
the Stand-By mode waiting for all permissives to be
met.
• Amperage
• Compressor VFD Amperage – Current draw by
each Scroll Compressor motor.
2. Upon all of the permissives being met the VRU will
start the Scroll Compressors.
• Oil Cooler VFD Amperage – Current draw by the
Oil Cooler Fan motor.
3. The Scroll Compressors will continue to run with
their speed varying based on where the Tank
Suction Pressure is in relation to the Target Tank
Suction Pressure set-point (and dead-band).
• Stabilizer Oil Heaters
• Scroll Compressor Motor(s)
• Oil Cooling Fan Motor
4. Normally the VRU will shut down when the Tank
Suction Pressure falls below the Compressor Stop
Tank Suction Pressure set-point and go back into
the Stand-By mode waiting for re-start based on
conditions.
• Blow-case Blow-down valves
• Pressure Equalization Valve
• Selectable groups of set-points for varying operating
conditions
COMPRESSOR VFD CONTROL
• Daily EPA data collection
• Tank Suction Pressure
When a compressor starts the VFD controlling that
compressor will be held at minimum speed (50%) for
a set amount of time (Initial Run Time before VFD A&B
Increases from Minimum Speed set-point). Once that
initial time has expired the PLC will control the VFD
speed via a PID control that monitors the Tank Suction
Pressure and by adjusting the VFD speed tries to main-
tain that pressure.
• Discharge Pressure
• Stabilizer Operating Temperature
• Compressor Run Time
• Compressor Average RPM (while running)
• Power Usage (kWH/Day)
• Mechanical Availability
If the Tank Suction Pressure is above the target Tank
Suction Pressure (+ dead-band) the VFD speed will con-
tinue to increase until the target pressure has been ob-
tained or the VFD reaches Maximum Speed (100%).
If the Tank Suction Pressure is below the target Tank
Suction Pressure (- dead-band) the VFD speed will
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Section 2 • Operational Descriptions
continue to decrease until the target pressure has been
obtained or the VFD reaches Minimum Speed (50%).
If the Tank Suction Pressure continues to drop and fall
below the Compressor Stop set-point the VRU will shut
down.
the compressor PLC to maintain warm oil. The heaters
cycle on and off to maintain a desired separator oil tem-
perature range.
PRESSURE EQUALIZING SOLENOID
The equalizing solenoid opens whenever the compres-
sors are stopped to equalize pressure between suction
and discharge of the compressor.
SAFETIES
The Vapor Recovery Unit (VRU) controller continuously
monitors operational and process data and annunciates
an alarm and/or stops the machine if any condition be-
comes abnormal. Two levels of safeties exist when an
abnormal condition is detected.
AIR COOLED OIL COOLER (VFD TYPE)
The VFD type air cooled oil cooler is a heat exchanger
that uses a fan running on a VFD to control the oil tem-
perature at its outlet.
• Alarm: If active, alarms are annunciated on the VRU
HMI in the Alarm Banner located on the Main Screen.
An alarm serves only as a warning to the operator; if
an alarm is active the machine is still allowed to run.
A PID controller adjusts the speed of the fan(s) to control
the temperature at the outlet of the oil cooler. When the
temperature of the oil at the outlet of the cooler exceeds
the desired temperature plus a dead-band, the fan(s)
will increase speed to add more cooling. When outlet
temperature drops below the desired temperature mi-
nus a dead-band, the fan(s) will decrease speed.
• Trip: If active, trips will shut the machine down or
not allow the VRU to start. Trips are annunciated on
the VRU HMI in the Trip Banner located on the Main
Screen. Trips are also logged in the EPA Event List.
The “Alarm Reset” push-button on the HMI Main Screen
will reset any active alarms or trips if the abnormal con-
dition has been removed. For a comprehensive list of
alarms and trips and possible causes, see the trouble-
shooting guide in this manual.
• When the compressor is stopped, the oil cooler fan(s)
will stop.
• When the compressor is running and the oil cooler
outlet temperature rises above the “Oil Cooler Start”
temperature set in the “Compressor Control Set-
Points” screen, the fan(s) will start at a minimum
speed.
EMERGENCY STOP
The Emergency Stop circuit in the compressor control
panel energizes the Master Control Relay, which pro-
vides power to PLC outputs that control heaters, motor
starters, valves, etc. The Master Control Relay may be
energized by pressing the “Control Power On” illumi-
nated push-button on the door of the compressor con-
trol panel. When the Master Control Relay is energized,
the “Control Power On” push-button will illuminate. The
following conditions must be satisfied to energize the
Master Control Relay:
• When the compressor is running and the oil cooler
outlet temperature is above the dead-band, the PID
controller will increase fan speed.
• When the compressor is running and the oil cooler
outlet temperature is below the dead-band, the PID
controller will decrease fan speed.
BLOW-CASE BLOWDOWN
TheVaporRecoveryUnit (VRU)hasaBlowcaseBlowdown
function that monitors the Scrubber for a High Level
condition. If that condition occurs the PLC will enable
the Blowcase Blowdown discrete output which in turn
energizes the Balancing Line (NO) and Supply Line (NC)
solenoids.
• Emergency Stop push-button on the door of the
compressor control panel must be pulled out.
• Any additional Emergency stops or safety devices
tied in to the Emergency Stop circuit must be reset.
• The compressor PLC must be booted up and
operational.
Typically a VRU contains Blowcase level switch that
not only has a Blowcase High Level contact but also a
Blowcase Low Level contact as well. When the Blowcase
Low Level has been reached the Blowcase Blowdown
discrete output is de-energized. If a VRU only contains a
High Level contact then once that contact transitions by
the level falling below the High Level then the Blowcase
Blowdown discrete output will de-energize.
• The 24-volt DC power supplies in the compressor
control panel must be powered up and OK.
• The “PLC Control Enable Relay” discrete PLC output
must be energized
OIL HEATERS
Immersion Heaters in the oil stabilizer are controlled by
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Section 3 • Overview Screens
Main Menu Screen
While the MAIN SCREEN is the screen that the HMI pow-
ers up in, or is typically the HMI screen that the opera-
tor sets the HMI to, the MAIN MENU Screen is the screen
used to navigate to all of other screens.
The user name to select is “MGR” and the password is
“1”.
Not only is the Login needed to navigate to some screens
but the operator must be logged in to change any of the
set-points.
Note that some of the HMI screen navigation buttons
are only accessible when the operator is logged in. The
Login function requires a User Name and a Password.
Figure 3-1. Main Menu Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
Main Screen
The Vapor Recovery Unit (VRU) has an HMI that contains
several screens. The Main screen is the screen that is
opened at power up and also the screen that an operator
would normally leave open.
each to be displayed for 2 seconds before the next Alarm
is displayed.
Note that anytime an Alarm occurs the Vapor Recovery
Unit will not shut down. Alarms serve as a warning to the
operator that the VRU outside of a desired range but not
enough to shut it down. The VRU not only will remain
running should an alarm occur but also can re-start with
an active alarm.
This Main screen contains VRU system status informa-
tion that allow an operator to view critical data.
TRIP BANNER
This is the Red Banner located towards the top of the
screen just below the screen name. Whenever there is
an active Trip this banner will become visible and display
all active Trips. The banner will cycle through each ac-
tive Trip allowing each to be displayed for 2 seconds be-
fore the next Trip is displayed.
STATUS BANNER
This is the green banner located just below the yellow
alarm banner. The purpose of the Status Banner is to dis-
play information to the operator as to what the VRU is
doing or what it is waiting for. This banner is not affected
directly by the Alarm Reset since it is for informational
purposes only.
Note that anytime a Trip occurs the Vapor Recovery Unit
will shut down. All trips must be reset before the VRU is
allowed to start again.
ELAPSED RUNTIME AND COMPRESSOR STARTS
ALARM BANNER
The VRU monitors runtime and displays the elapsed
time that it has run in Hours and Minutes. Also every
time that the VRU starts the compressors a “Compressor
Start” is logged and displayed.
This is the yellow banner located just below the red trip
banner. Whenever there is an active Alarm this banner
will become visible and display all active Alarms. The
banner will cycle through each active Alarm allowing
Figure 3-2. Main Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
TANK SUCTION PRESSURE
VFD A and VFD B AMPARAGE
The Tank Suction Pressure is the pressure that the VRU
monitors for starting and stopping the compressors. It
is also monitored and used by the PLC to regulate the
speed at which the Compressor (A & B) VFDs are run at.
The PLC reads each Compressor VFD running current
over Ethernet. It is used for safeties as well as for EPA
data.
OIL COOLER OUTLET VFD SPEED COMMAND
SUCTION PRESSURE
The percentage of commanded speed is displayed. This
is the value that the PLC’s PID controller commands the
Oil Cooler Fan VFD to run.
The Suction Pressure differs from the Tank Suction
Pressure in that it is used only for a safety (Alarm and
Trip) as well as used to calculate the VRU differential
pressure (also a safety).
OIL COOLER OUTLET VFD AMPARAGE
The PLC reads the Oil Cooling Fan VFD running current
over Ethernet. It is used for safeties as well as for EPA
data.
DISCHARGE PRESSURE
The Discharge Pressure is used not only as a safety but
also to calculate the Differential Pressure (also a safety).
UNIT START
DISCHARGE TEMEPRATURE
The UNIT START button on the HMI is used to start the
VRU. Initially the VFR will be in the Stand-By mode until
all of the run permissive are met.
The Discharge Temperature is used for as a safety.
DIFFERENTIAL (DP-SP) PRESSURE
The Differential Pressure is in the units of (PSID) and is
the Discharge Pressure minus the Suction Pressure. The
Differential Pressure is used as a VRU safety.
UNIT STOP
The UNIT STOP button on the HMI is used to stop the
VRU at anytime. Once the UNIT STOP button is pressed
the VRU will not re-start unless the UNIT START button
is pressed to put the VRU back into the Stand-By Mode.
STABILIZER OIL TEMPERATURE
The Stabilizer Oil Temperature is monitored. It is used
to control the Stabilizer Oil Heaters based on operator
set-points. It is also used as a run permissive (the Oil
Temperature must be at least 150°F) before the VRU can
start a compressor. The Stabilizer Oil Temperature is
also a VRU safety.
ALARM RESET (FAULT RESET)
The ALARM RESET (FAULT RESET) button on the HMI has
three functions when pressed.
1. Will clear Alarms when the conditions that caused
the alarm are no longer are preset.
VFD A and VFD B SPEED COMMAND
2. Will clear Trips when the conditions that caused the
trip are no longer are preset.
The percentage of commanded speed is displayed. This
is the value that the PLC’s PID controller commands the
compressor VFD(s) to run. Both VFD A and VFD B run at
the same time and at the same speed.
3. Will send
a
reset command each VFD (over
Ethernet) to reset a VFD Fault if one is present.
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Section 3 • Overview Screens
Compressor Control Screen
The Compressor Control screen contains set-points
used to control the VRU. These set-points are entered
at the time of VRU commissioning and typically are left
alone unless the control parameters of the system have
changed.
COMPRESSOR ACTUAL PRESSURE
The Vapor Recovery Unit (VRU) Tank Suction Pressure is
displayed to the right of the Start and Stop set-points for
reference purposes.
Note that all BLUE displays also allow the data points to
changed but only when an operator has properly logged
into the HMI. If the operator has not logged in the set-
points are read only (not read/write).
STABILIZER OIL HEATER SET-POINT
This set-point is the Target Temperature of the Oil in
the Stabilizer. If the actual temperature is below this
set-point (-DB) the PLC will command the Oil Heaters to
energize.
COMPRESSOR START PRESSURE
The Compressor Start Pressure set-point is the pressure
that the Tank Suction Pressure (actual value is displayed
to the right) must reach before the compressors are
commanded to automatically run (provided that all of
the run permissives are also met).
STABILIZER OIL HEATER DEADBAND
This is a value that is referenced to the Stabilizer Oil
Heater set-Point which is used to calculate an actual
Start and Stop value for the Oil Heaters to operate from.
COMPRESSOR STOP PRESSURE
TANK SUCTION PRESSURE SET-POINT
The Compressor Stop Pressure set-point is the pressure
that the Tank Suction Pressure must fall to before the
compressors are commanded to automatically stop.
This is the target Tank Suction Pressure that the PLC’s
PID controller will use to compare against the actual
Tank Suction Pressure.
Figure 3-3. Compressor Control Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
TANK SUCTION PRESSURE DEADBAND
OIL COOLER TEMPERATURE: TARGET
This is a value that is referenced to the Tank Suction
Pressure set-point which is used to calculate a dead-
band around the target where no change in compressor
VFD speed will occur.
Once the Oil Cooler Fan has started the PLC’s PID con-
troller for the Cooling Fan will regulate the fan speed
based on what the actual Oil Cooler Temperature is as
compared to the Target set-point and vary the speed of
the speed reference command to the Fan VFD.
TANK SUCTION PRESSURE
OIL COOLER TEMPERATURE: DEADBAND
The Vapor Recovery Unit (VRU) Tank Suction Pressure is
displayed to the right of the Tank Suction Pressure Set-
point and Dead-Band set-points for reference purposes.
This is a value that is referenced to the Oil Cooler
Temperature set-point which is used to calculate a dead-
band around the target where no change in compressor
VFD speed will occur.
INITIAL RUN TIME BEFORE VFD A/B INCREASE
FROM MINIMUM SPEED
VFD A&B ACCEL/DECEL RATE
This initial runtime set-point is used to set a time (in
seconds) whereupon when the compressors are started
their speed will be held at minimum (50%) to allow the
compressor oil to stabilize in the compressors before
additional load is placed on them. Once this time has
expired the Compressor VFD(s) will follow the speed
reference command as determined by the PLC’s PID
controller.
The acceleration and acceleration rates for the
Compressor VFDs are written down to each of the VFDs.
These rates control how fast the VFDs can change their
running speed when a change in speed reference from
the PLC’s PID controller occurs.
OIL COOLER VFD ACCEL/DECEL RATE
The acceleration and acceleration rates for the Oil Cooler
VFD are written down to the VFD. These rates control
how fast the VFD can change its running speed when a
change in speed reference from the PLC’s PID controller
occurs.
OIL COOLER TEMPERATURE: START
If the Oil Cooler Temperature rises to or above this set-
point the Oil Cooler Fan (VFD) will start.
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Section 3 • Overview Screens
Alarm and Trip Setpoints Screen
The Alarm and Trip set-points are used as safeties for the
protection of the Vapor Recovery Unit. These Alarms
and Trips are compared against the actual (real time)
values of the signals.
TRIPS
There are two types of Trips, Low-Low and High-High.
• Low-Low Trip - For a Low-Low Trip to occur the Actual
value being monitored must drop below the Low-
Low Trip set-point. Once that occurs the VRU will
shut down and the appropriate Low-Low Trip will be
triggered and then displayed in the MAIN SCREEN’s
Trip Banner (till it has been reset). The Trip will also
be recorded in the EPA Event List.
ALARMS
There are two types of Alarms, Low and High.
• Low Alarm - For a Low Alarm to occur the Actual value
being monitored must drop below the Low Alarm set-
point. Once that occurs the appropriate Low Alarm
will be triggered and then displayed in the MAIN
SCREEN’s Alarm Banner (till it has been reset). The
VRU will continue to run with a Low Alarm active.
• High=High Trip - For a High-High Trip to occur the
Actual value being monitored must rise above the
High-High Trip set-point. Once that occurs the VRU
will shut down and the appropriate High-High Trip
will be triggered and then displayed in the MAIN
SCREEN’s Trip Banner (till it has been reset). The Trip
will also be recorded in the EPA Event List.
• High Alarm - For a High Alarm to occur the Actual
value being monitored must rise above the High
Alarm set-point. Once that occurs the appropriate
High Alarm will be triggered and then displayed in
the MAIN SCREEN’s Alarm Banner (till it has been re-
set). The VRU will continue to run with a High Alarm
active.
• Re-starting the VRU after a Trip has occurred.
• When the VRU the start command is lost.
• Reset all Trips. The VRU cannot run with an active
Trip.
• Press the “Unit Start” to put the VRU in Stand-
By mode awaiting all run permissives to become
true.
Figure 3-4. Alarms and Trips Setpoint Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
Pressure Calibration Screen
The PRESSURE CALIBRATION screen is used at the VRU’s
commissioning, or if a pressure sensor has to be replaced.
The purpose of this screen is to set the Raw calibration of
the Analog Channel to the settings on the sensor. There
is an offset to adjust the Calibrated (Base Units) by using
the ± Offset set-point. The calibrated pressure is PSIG.
Differential pressure, which is a calculated value of
Discharge Suction Pressure, must use pressures
with the same units. The Displayed units of both the
Suction and Discharge can be selected in different units.
Differential units are always in PSID (PSI differential).
-
There is a selection on how you want your pressure units
displayed throughout the rest of the HMI. The Display
Actual Values are what the Alarms, Trips and Compressor
control settings are compared to.
Figure 3-5. Pressure Calibration Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
Temperature Calibration Screen
The TEMPERATURE CALIBRATION screen is used to set an
offset to the RAW temperature from the RTD Inputs.
Figure 3-6. Temperature Calibration Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
3 – 8
Section 3 • Overview Screens
Pressure Control - PID Screen
The PRESSURE CONTROL – PID screen allows the op-
erator to tune the PID that controls Compressor VFD(s)
speed reference signal and how it reacts to the Tank
Suction Pressure.
LOOP UPDATE TIME
Time in seconds (or fractions of a second) for how the
PID instruction should recalculate the commanded
speed reference signal for the Compressor VFDs.
Typically the PID is set-up at the time of commissioning
and do not need to be further modified.
PROPORTIONAL GAIN (Kp)
The PID Instruction is selected to run in Independent
Mode. In the Independent Mode the Proportional Gain
is unit less.
TANK SUCTION PRESSURE SET-POINT
This is the target pressure that the PLC’s PID control-
ler will use to compare against the actual Tank Suction
Pressure.
INTEGRAL GAIN (Ki)
The PID Instruction is selected to run in Independent
Mode. In the Independent Mode the Integral Gain Ki or
Ti (Reset Gain) units are (1/sec).
DEADBAND
This is a value that is referenced to the Tank Suction
Pressure set-point which is used to calculate an error
range above and below the target where no change in
compressor VFD speed will occur.
DERRIVATIVE GAIN (Kd)
The PID Instruction is selected to run in Independent
Mode. In the Independent Mode the Derivative Gain is
in seconds.
VFD SPEED (%)
This is the speed reference signal that the PID controller
is sending to the Compressor VFDs (50-100%).
Figure 3-7. Pressure Control - PID Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
MINIMUM SPEED (%)
This is the lowest speed that the Compressor VFD speed
reference can go (50%).
TANK SUCTION PRESSURE ACTUAL
The Vapor Recovery Unit (VRU) Tank Suction Pressure is
the pressure that the VRU is controlling to.
ERROR
The Error is the difference between the actual Tank
Suction Pressure and the target pressure.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
Oil Cooling Fan - PID Screen
The OIL COOLING FAN – PID screen allows the operator
to tune the PID controls the Oil Cooling Fan speed ref-
erence signal and how it reacts to the Oil Cooler Outlet
temperature.
LOOP UPDATE TIME
Time in seconds (or fractions of a second) for how the
PID instruction should recalculate the commanded
speed reference signal for the Oil Cooling Fan VFDs.
Typically the PID is set-up at the time of commissioning
and do not need to be further modified.
PROPORTIONAL GAIN (Kp)
The PID Instruction is selected to run in Independent
Mode. In the Independent Mode the Proportional Gain
is unit less.
TARGET OIL TEMPERATURE SET-POINT
This is the target temperature that the PLC’s PID con-
troller will use to compare against the actual Oil Cooler
Outlet temperature.
INTEGRAL GAIN (Ki)
The PID Instruction is selected to run in Independent
Mode. In the Independent Mode the Integral Gain Ki or
Ti (Reset Gain) units are (1/sec).
DEADBAND
This is a value that is referenced to the Oil Cooler Outlet
temperature set-point which is used to calculate an error
range above and below the target where no change in
Oil Cooling Fan VFD speed will occur.
DERRIVATIVE GAIN (Kd)
The PID Instruction is selected to run in Independent
Mode. In the Independent Mode the Derivative Gain is
in seconds.
VFD SPEED (%)
This is the speed reference signal that the PID controller
is sending to the Oil Cooling Fan VFD.
Figure 3-8. Oil Cooling Fan - PID Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
MINIMUM SPEED (%)
This is the lowest speed that the Oil Cooling Fan VFD
speed reference can go (10%).
TANK SUCTION PRESSURE ACTUAL
The Vapor Recovery Unit (VRU) Oil Cooler Outlet tem-
perature is the temperature that the VRU is controlling
to.
ERROR
The Error is the difference between the actual Oil Cooler
Outlet temperature and the target temperature.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
3 – 12
Section 3 • Overview Screens
Discrete IO Status Screen
The purpose of the DISCRETE IO STATUS Screen is to al-
low the operator to view the status of the incoming sig-
nals as well as the status of the discrete PLC outputs.
Status message “(S021) Compressor in Standby Mode
waiting for Customer Trip Input” and Trip message
“(T002) Trip: Customer Trip Input (Off) (Rem. Trip)” are
associated with this input.
Note that some of the Input signals have been inverted
from their actual physical state and will be noted as such.
Remote Run Permissive
DC INPUTS
Master Control Relay (CRMA)
The Remote Run Permissive is an optional input that is a
permissive for a compressor to start. From the factory
this input has jumper installed which must be removed
if used on-site.
Whenever the Master Control Relay is energized this in-
put should be on. It is used as a permissive for a com-
pressor to start or run. A loss of the MCR input will cause
the VRU to fault.
Status messages “(S002) Status: Waiting for Remote Run
Permissive” and “(S022) Compressor in Standby Mode
waiting for Remote Run Permissive Input” are associated
with this input.
Status message “(S020) Compressor in Standby Mode
waiting for MCR relay Input” is associated with this input.
Compressor A Running
Customer Trip Input
Input is true whenever the VFD/Starter for Compressor
A is energized.
The Customer Trip Input is an optional input that is a op-
tional customer defined trip. From the factory this input
has jumper installed which must be removed if used on-
site. A loss of the Customer Trip Input will cause the VRU
to fault.
Status message “(S004) Status: VFD A Motor Running
(VFD A Run)” is associated with this input.
Figure 3-9. Discrete IO Status Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
5 seconds continuously. The Trip message is triggered
when there is a high level for 30 seconds continuously.
Compressor B Running
Input is true whenever the VFD/Starter for Compressor
B is energized.
Alarm message “(A010) Alarm: Blowcase High Level
(LSH300)” and Trip message “(T010) Trip: Blowcase
High Level (LSH300)” are associated with this input.
Status message “(S005) Status: VFD B Motor Running
(VFD B Run)” is associated with this input.
Oil Cooler Fan Running
Compressor A Fault
Input is true whenever the Oil Cooler Fan VFD/Starter is
energized.
This input actually monitors the Compressor A Drive Ok
contact of VFD A. Normally this input is on (for Drive Ok)
but it is inverted for use in the PLC as a Drive Fault.
Status message “(S008) Status: Oil Cooler Running (OC
Run)” is associated with this input.
Trip message “(T004) Trip: VFD A Drive Fault (VFD A
Fault)” is associated with this input.
Oil Cooler Fan Vfd Fault
This input actually monitors the Oil Cooling Fan Drive Ok
contact of the VFD. Normally this input is on (for Drive
Ok) but it is inverted for use in the PLC as a Drive Fault.
Compressor B Fault
This input actually monitors the Compressor B Drive Ok
contact of VFD B. Normally this input is on (for Drive Ok)
but it is inverted for use in the PLC as a Drive Fault.
Trip message “(T009) Trip: Oil Cooler VFD Fault (OC VFD
Fault)” is associated with this input.
Trip message (T005) Trip: VFD B Drive Fault (VFD B Fault)”
is associated with this input.
DC OUTPUTS
PLC Control Enable Relay
Scrubber High Level
Once the CLX processor has determined to be ok and a
one second delay has occurred enable the PLC control
Enable Relay to allow the operator to enable the Master
Control Relay (MCR) via the white PB on the Control
Panel. Loss of this signal will make the MCR drop out.
This input monitors the level of the Scrubber for a High
Level state. Upon a high level the Blowcase Blowdown
output is energized controlling the Balancing Line and
Supply Line solenoids.
Stabilizer Low Level
Compressor A Start Command
This input monitors the Stabilizer for a low oil level.
Should a low level be detected the Stabilizer Heaters will
be prevented from being enabled. This input is normally
high and opens on a low condition. This input is inverted
for use in the PLC. When lit this indicates a Low Level.
Upon the VRU in the Stand-By Mode and all conditions
to run being true, a start command is sent to the VFD for
compressor A.
Trip message “ (T007) Trip: Stabilizer Low Level Trip” is
associated with this input.
Compressor B Start Command
Upon the VRU in the Stand-By Mode and all conditions
to run being true, a start command is sent to the VFD for
compressor A.
Oil Filter High Differential
This input monitors the differential pressure at the Oil
Filter. This input is normally high signifying normal dif-
ferential pressure and is inverted in the PLC. The indica-
tor on denotes a high differential condition.
Stabilizer Heater Start Command
The STABILIZER HEATER START COMMAND utilizes two
set-points from the Compressor Control HMI screen.
The “Stabilizer Oil Heater – Set-Point” and the “Stabilizer
Heater – Dead-band” are used to develop a Start and Stop
temperature for the Stabilizer Heater Start Command.
Alarm message “(A008) Alarm: Oil Filter High Differential
Pressure (PDSHH100)” and Trip message “(T008) Trip:
Oil Filter High Differential Pressure (PDSHH100)” are as-
sociated with this input.
Oil Cooler Start Command
Blowcase High Level
The OIL COOLER START COMMAND is enabled whenever
the compressors are running and there is a need for the
Oil Cooler VFD to run.
The Blowcase High Level is used to drive an alarm and a
trip. The Alarm is triggered when there is a high level for
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
Blowcase Blowdown
The BLOWCASE BLOWDOWN command is initiated upon
the detection of a Scrubber High Level condition. Upon
a high level the Blowcase Blowdown output is energized
controlling the Balancing Line and Supply Line solenoids.
Pressure Equalizer Solenoid
The PRESSURE EQUALIZATION SOLENOID is energized
whenever the compressors are not running. This is used
to equalize the Discharge to Suction pressure.
Remote Alarm Notification
This output is enabled whenever an active Alarm is pres-
ent. Any active Alarm will be displayed on the HMI’s
MAIN SCREEN. This output is optionally used by the cus-
tomer for their own purpose.
Remote Trip Notification
This output is enabled whenever an active Trip is pres-
ent. Any active Trip will be displayed on the HMI’s MAIN
SCREEN. This output is optionally used by the customer
for their own purpose.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
VFD Status Screen
The VFD STATUS Screen is used to display an overall sta-
tus of the three VFDs that the VRU uses.
• (019) I2t on braking resistor (It.br)
• (020) I2t on drive output current (It.AC)
• (021) Drive over-heat (IGBT junctions) based on
thermal model (O.ht1)
VFD A FAULT, VFD B FAULT, & VFD OIL COOLER
FAULT
• (022) Drive over-heat based on heat-sink temper-
ature (O.ht2)
These three banners are driven off of the VFD alarm/trip
codes and display’s not only the numerical code but a
brief description of the event. This data is read from the
VFD(s) over Ethernet.
• (024) Motor thermistor trip (th)
• (026) +24V or Digital output overload (O.Ld1*)
• (027) Drive over-heat (O.ht3)
• VFD Fault Codes
• (028) Analog input 1 current mode: current loss
(cL1)
• (000) No VFD Fault
• (001) DC bus under voltage (UU***)
• (002) DC bus over voltage (OU)
• (003) AC instantaneous over current (OI.AC**)
• (030) Serial comms timeout (SCL)
• (031) Internal drive EEPROM failure (EEF)
• (032) High input voltage phase imbalance or in-
put phase loss (PH)
• (004) Braking resistor instantaneous current trip
(OI.br**)
• (033) Failure to measure stator resistance (rS)
• (035) Trip initiated from the control word (CL.bt)
• (040-089) User trip (t040-t089)
• (006) External trip (Et)
• (007) Over-speed (O.SPd)
• (018) Auto-tune stopped before completion
(tunE)
• (090) Divide by zero (t090)
• (091) Access to non-existent parameter (t091)
Figure 3-10. VFD Status Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
• (092) Write to a read only parameter (t092)
MOTOR VOLTAGE
• (094) Write a value to a parameter which is out of
range (t094)
This is the Motor Voltage while running.
• (095) Virtual memory stack overflow (t095)
MOTOR SPEED
• (096) Invalid operating system call (t096)
This is the Motor Speed in RPM while running.
• (097) Enabled with no LogicStick inserted or
LogicStick removed (t097)
MOTOR ACTIVE CURRENT
• (098) Invalid instruction (t098)
• (099) Invalid function block argument (t099)
• (100) Drive reset (-)
This is the Motor Current while running.
OUTPUT POWER
• (102) Power module rectifier over temperature
This is the Motor kilowatts (kW) while running. Total
output power of the drive (positive for power flow out
of the drive’s output terminals). Output power of the
drive is calculated from the in phase components of volt-
age and current such that the total real power output is
measured.
(O.ht4)
• (182) SmartStick data error (C.Err)
• (183) Data does not exist (C.dAt)
• (185) SmartStick read/write fail (C.Acc)
• (186) Rating change (C.rtg)
• (189) Overload on current loop input (analog in-
put 1). (O.cL)
VFD COMMUNICATIONS
This is the Ethernet communications status between the
VFD and the CLX processor. The status needed to run in
“Ok” (or Running).
• (199) Destination parameter clash (dESt)
• (200) Solutions Module hardware fault (SL.HF)
• Standby - The controller is powering up.
• (201) Solutions Module watchdog timeout (SL.
tO)
• Faulted - Any of the MODULE object’s connections to
the associated module fail. This value should not be
used to determine if the module failed because the
MODULE object leaves this state periodically when
trying to reconnect to the module. Instead, test for
Running state (16#4000). Check for Fault Code not
equal to 0 to determine if a module is faulted. When
Faulted, the Fault Code and Fault Info attributes are
valid until the fault condition is corrected.
• (202) Solutions Module error (SL.Er)
• (203) Solutions Module not installed (SL.nF)
• (204) Solutions Module different installed (SL.dF)
• (220) Power stage - code error (HF20)
• (221) Power stage - unrecognized frame size
(HF21)
• (222) OI failure at power up (HF22)
• (223) DSP software overrun (HF23)
• (224) Not used (HF24)
• Validating - The MODULE object is verifying MODULE
object integrity prior to establishing connections to
the module.
• Connecting - The MODULE object is initiating con-
nections to the module.
• (225) DSP Communications failure (HF25)
• (226) Soft start relay failed to close (HF26)
• (227) Power stage thermistor fault (HF27)
• Running - All connections to the module are estab-
lished and data is successfully transferring.
• (228) Power circuit thermistor 2 or 3 fault/internal
fan fault (HF28)
• Shutting down - the MODULE object is in the process
of shutting down all connections to the module.
• (229) Fan failure (current too high) (HF29)
• Inhibited - The MODULE object is inhibited (the in-
hibit bit in the Mode attribute is set).
• (230) DCCT wire break trip from power module
(HF30)
• Waiting - The parent MODULE object upon which this
MODULE object depends is not running
• (231) Internal capacitor bank fan failure (size 4
and larger) (HF31)
• (232) Power circuit temperature feedback multi-
plexor failure (HF32)
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
3 – 17
Section 3 • Overview Screens
EPA Data Screen
COMPRESSOR RPM (AVERAGE)
The EPA DATA Screen shows data as it is being collected
today as well as the data that was recorded for the previ-
ous day.
This is the average Compressor RPM over a 24 hour pe-
riod only while a compressor is running.
POWER USAGE (KWH/DAY)
TANK SUCTION PRESSURE (AVERAGE)
This is the totalized value over a 24 period of the three
VFD kW signals.
This is the average Tank Suction Pressure over a 24 hour
period only while a compressor is running.
MECHANICAL AVAILABLITY (%)
DISCHARGE PRESSURE (AVERAGE)
The amount of time that the VRU is not Tripped (wheth-
er running or not). Should ever the VRU be tripped it is
not available to run.
This is the average Discharge Pressure over a 24 hour pe-
riod only while a compressor is running.
STABILIZER OPERATING TEMPERATURE (AVERAGE)
EPA RECORD (YEAR)
This is the average Stabilizer Operating Temperature
over a 24 hour period only while a compressor is running.
This is the year of the daily record.
EPA RECORD (MONTH)
COMPRESSOR RUN TIME (RUNNING TOTAL)
This is the month of the daily record.
The total time the VRU was running (in hours) over a 24
hour period.
EPA RECORD (DAY)
This is the day of the month of the daily record.
Figure 3-11. EPA Data Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
3 – 18
Section 3 • Overview Screens
EPA Event List Screen
The EPA EVENT LIST Screen only logs Trip level events. It
holds the last 100 Trip events.
If multiple trips occur at the same time all will be logged.
Figure 3-12. EPA Event List Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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Section 3 • Overview Screens
Options Screen
The “Clear EPS Event List” allows an operator to clear out
the EPA Event List if needed. Typically this may be done
after start up to clear out Trips that may have occurred
while setting set-points and calibration.
The OPTIONS Screen is only accessible when logged in.
From this screen there is one option to select which is the
Auto Restart On Power-Up. That option when selected
will allow the a VRU that was either in the Stand-By Mode
or with a compressor running to re-start on a power up.
Should this option be de-selected the VRU will drop out
of the Stand-By mode requiring an operator to press the
Start button on the HMI’s Main Screen.
Figure 3-13. Options Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
3 – 20
Section 3 • Overview Screens
Set PLC Date & Time Screen
This screen allows an operator to set the CLX (PLC) Date
and Time to whatever value they desire. Typically this
screen is used at start-up or due to Daylight Savings
Time. This Date and Time are what is logged into the
EPA Event List logs.
Figure 3-14. Set PLC Date & Time Screen
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
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VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
3 – 22 / Blank
Section 4 • Alarms, Trips and Status Messages
Alarm Messages
Message: (A008) Alarm: Oil Filter High Differential
Pressure.
Message: (A015) Alarm: Low Oil Cooler Outlet
Temperature.
Cause:
Oil Filter High Differential (PS2201) is
detected.
Cause:
Reset:
Oil Cooler Outlet Temperature is less than or
equal to Oil Cooler Outlet Temperature Low
(Alarm) set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Once the condition has cleared Press Alarm
Reset push-button.
Message: (A010) Alarm: Blowcase High Level.
Message: (A016) Alarm: High Oil Cooler Outlet
Temperature.
Cause:
Reset:
Blowcase High Level (FLT2221) is detected.
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Oil Cooler Outlet Temperature is greater than
or equal to Oil Cooler Outlet Temperature
High (Alarm) set-point.
Message: (A011) Alarm: High Discharge Pressure.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Compressor Discharge Pressure w/Offset is
greater than or equal to Discharge Pressure
High (Alarm) set-point.
Message: (A017) Alarm: High Discharge Outlet
Temperature.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Discharge Outlet Temperature is greater than
or equal to Discharge Outlet Temperature
Low-Low (Alarm) set-point.
Message: (A012) Alarm: Low Suction Pressure.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Compressor Suction Pressure w/Offset is less
than or equal to Suction Pressure Low (Alarm)
set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (A018)
Alarm:
Low
Stabilizer
Oil
Temperature.
Cause:
Reset:
Stabilizer Oil Temperature is less than or equal
to Stabilizer Oil Temperature Low (Alarm)
set-point.
Message: (A013) Alarm: Low Differential Pressure.
Cause:
Whenever the compressor has started a 30
second delay occurs before the monitoring if
the Compressor Differential Pressure (DP-SP)
is less than or equal to Differential Pressure
Low (Alarm) set-point.
Once the condition has cleared Press Alarm
Reset push-button.
Message: (A019) Alarm: High Stabilizer Oil
Temperature.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Stabilizer Oil Temperature is greater than
or equal to Stabilizer Oil Temperature High
(Alarm) set-point.
Message: (A014) Alarm: Low Tank Suction Pressure.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Tank Suction Pressure w/Offset is less than or
equal to Tank Suction Pressure Low (Alarm)
set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
4 – 1
Section 4 • Alarms, Trips and Status Messages
Message: (A028) Alarm: Compressor VFD A High
Motor Amps.
Cause:
VFD A Motor Active Current (A) (Pr. 00.89) is
greater than or equal to VFD A/B Amps High
(Alarm) set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (A029) Alarm: Compressor VFD B High
Motor Amps.
Cause:
VFD B Motor Active Current (A) (Pr. 00.89) is
greater than or equal to VFD A/B Amps High
(Alarm) set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (A030) Alarm: Oil Cooler VFD High Motor
Amps.
Cause:
VFD Oil Cooler Motor Active Current (A) (Pr.
00.89) is greater than or equal to VFD Oil
Cooler Amps High (Alarm) set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
4 – 2
Section 4 • Alarms, Trips and Status Messages
Trip Messages
Message: (T001) Trip: MCR Not Energized/E-Stop
Active (MCR).
Message: (T009) Trip: Oil Cooler VFD Fault.
Cause:
Reset:
Oil Cooler Fan VFD has faulted.
Cause:
Reset:
Master Control Relay input is off.
Press Reset Alarm push-button to clear the
VFD Fault and system Trip.
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T010) Trip: Blowcase High Level.
Message: (T002) Trip: Customer Trip Input (Off) (Rem.
Trip).
Cause:
Blowcase High Level (FLT2221) has been on
for 30 seconds continuously.
Cause:
Reset:
Customer Trip input is off.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T011) Trip: High Discharge Pressure.
Message: (T003) Trip: Faulted I/O Module or
Connection.
Cause:
Compressor Discharge Pressure w/Offset is
greater than or equal to Discharge Pressure
High-High (Trip) set-point.
Cause:
Reset:
An IO Module fault has been detected.
Once the condition has cleared Press Alarm
Reset push-button.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T004) Trip: VFD A Drive Fault (VFD A Fault).
Message: (T012) Trip: Low Suction Pressure.
Cause:
Reset:
Compressor VFD A has faulted.
Cause:
Compressor Suction Pressure w/Offset (EU)
is less than or equal to Suction Pressure Low-
Low (Trip) set-point.
Press Reset Alarm push-button to clear the
VFD Fault and system Trip.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T005) Trip: VFD B Drive Fault (VFD B Fault).
Cause:
Reset:
Compressor VFD B has faulted.
Message: (T013) Trip: Low Differential Pressure.
Press Reset Alarm push-button to clear the
VFD Fault and system Trip.
Cause:
Whenever the compressor has started a 30
second delay occurs before the monitoring if
the Compressor Differential Pressure (DP-SP)
is less than or equal to Differential Pressure
Low-Low (Trip) set-point.
Message: (T007) Trip: Stabilizer Low Level Trip.
Cause:
Reset:
Stabilizer Low Level (FLT2181) detected.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T014) Trip: Low Tank Suction Pressure.
Message: (T008) Trip: Oil Filter High Differential
Pressure.
Cause:
Tank Suction Pressure w/Offset is less than or
equal to Tank Suction Pressure Low-Low (Trip)
set-point.
Cause:
Oil Filter High Differential (PS2201) has been
on for 30 seconds continuously.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
4 – 3
Section 4 • Alarms, Trips and Status Messages
Message: (T016) Trip: High Oil Cooler Outlet
Temperature.
Message: (T022) Trip: Out of Range: Tank Suction
Pressure.
Cause:
Oil Cooler Outlet Temperature is greater than
or equal to Oil Cooler Outlet Temperature
High-High (Trip) set-point.
Cause:
Reset:
Tank Suction Pressure Input Fault, Under-
Range, or Over-Range.
Once the condition has cleared Press Alarm
Reset push-button.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T023) Trip: Runaway Protection Active.
Cause:
Either a false start or an uncontrolled run has
been detected.
Message: (T017) Trip: High Discharge Outlet
Temperature.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Discharge Outlet Temperature is greater than
or equal to Discharge Outlet Temperature
Low-Low (Trip) set-point.
Message: (T024) Trip: Out of Range: Oil Cooler Outlet
Temperature.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Oil Cooler Outlet Temperature Input Fault,
Under-Range, or Over-Range.
Message: (T018) Trip: Low Stabilizer Oil Temperature.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Compressor Start (Run in Auto) = 1 and
Stabilizer Oil Temperature is less than or equal
to Stabilizer Oil Temperature Low-Low (Trip)
set-point.
Message: (T025) Trip: Out of Range: Discharge Outlet
Temperature.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Discharge Outlet Temperature Input Fault,
Under-Range, or Over-Range.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T019) Trip: High Stabilizer Oil Temperature.
Cause:
Stabilizer Oil Temperature is greater than or
equal to Stabilizer Oil Temperature High-High
(Trip) set-point.
Message: (T026) Trip: Out of Range: Stabilizer Oil
Temperature.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Stabilizer Oil Temperature Input Fault, Under-
Range, or Over-Range.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T020) Trip: Out of Range: Compressor
Discharge Pressure.
Cause:
Compressor Discharge Pressure Input Fault,
Under-Range, or Over-Range.
Message: (T029) Trip: VFD A Trip Detected.
Cause:
There is a 10 second delay after system power
up to allow establishing communications
with VFD A. A loss in communications after
the 10 second delay will cause a trip to occur.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T021) Trip: Out of Range: Compressor
Suction Pressure.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Cause:
Compressor Suction Pressure Input Fault,
Under-Range, or Over-Range.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
4 – 4
Section 4 • Alarms, Trips and Status Messages
Message: (T030) Trip: VFD B Trip Detected.
Cause:
There is a 10 second delay after system power
up to allow establishing communications
with VFD B. A loss in communications after
the 10 second delay will cause a trip to occur.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T031) Trip: Oil Cooler VFD Trip Detected.
Cause:
There is a 10 second delay after system power
up to allow establishing communications
with the Oil Cooler VFD. A loss in communi-
cations after the 10 second delay will cause a
trip to occur.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T032) Trip: Compressor VFD A High Motor
Amps.
Cause:
VFD A Motor Active Current is greater than
or equal to VFD A/B High-High Amps (Trip)
set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T033) Trip: Compressor VFD B High Motor
Amps.
Cause:
VFD B Motor Active Current is greater than
or equal to VFD A/B High-High Amps (Trip)
set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
Message: (T034) Trip: Oil Cooler VFD High Motor
Amps.
Cause:
Oil Cooler VFD Motor Active Current is great-
er than or equal to Oil Cooler VFD High-High
Amps (Trip) set-point.
Reset:
Once the condition has cleared Press Alarm
Reset push-button.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
4 – 5
Section 4 • Alarms, Trips and Status Messages
Status Messages
Message: (S001) Status: Compressor Started.
Message: (S022) Status: Compressor in Standby Mode
waiting for Remote Run Permissive Input.
Cause:
All conditions have been met for the
Compressor to run.
Cause:
Compressor In Standby Mode (Ready to Start)
and waiting for the Remote Run Permissive in-
put on.
Message: (S002) Status: Waiting for Remote Run
Permissive.
Message: (S023) Status: Compressor in Standby Mode
waiting for Valid Compressor set-points.
Cause:
Remote Run Permissive input is low.
Cause:
Compressor In Standby Mode (Ready to
Start) and waiting for the Alarm, Trip, and
Compressor Control set-points order check to
be OK.
Message: (S004) Status: VFD A Motor Running.
Cause: Compressor A Running input is high.
Message: (S005) Status: VFD B Motor Running.
Cause: Compressor B Running input is high.
Message: (S024) Status: Compressor in Standby Mode
waiting on Low Tank Suction Start Pressure.
Cause:
Compressor In Standby Mode (Ready to Start)
and waiting for the Tank Suction Pressure
w/Offset to be greater than or equal to the
Compressor Tank Suction Pressure Start
set-point.
Message: (S008) Status: Oil Cooler Running.
Cause: Oil Cooler Fan Running input is high.
Message: (S010) Status: Blowcase Blowdown
Solenoid(s) Enabled.
Message: (S025) Status: Compressor in Standby Mode
waiting for Stabilizer Temperature to be
above target lower deadband.
Cause:
Blowcase Blowdown (CR2621) out is on
(Balancing Line (NO) Supply Line (NC)).
Cause:
Compressor In Standby Mode (Ready to Start)
and waiting for the Stabilizer Oil Temperature
to be greater than 180.
Message: (S018) Status: Stabilizer Heater Running.
Cause:
Stabilizer Heater Start Command (CR20581)
is on.
Message: (S020) Status: Compressor in Standby Mode
waiting for MCR relay Input.
Cause:
Compressor is in Standby Mode (Ready to
Start) and waiting for the Master Control
Relay (CRMA) to be energized.
Message: (S021) Status: Compressor in Standby Mode
waiting for Customer Trip Input.
Cause:
Compressor is in Standby Mode (Ready to
Start) and waiting for the Customer Trip input
on.
VRU PLC • Operation Manual •Vilter/Emerson • 35391CV
4 – 6
35391CV Rev. 0a (4/14) Emerson and Vilter are trademarks of Emerson Electric Co. or one of its affiliated companies. © 2014 Emerson Climate Technologies, Inc. All rights reserved. Printed in the USA.
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