Westport LNG User manual

INS-10009982
Rev 02
Calibrating the LNG Tank Level Sensor Signal
Conditioner (LSSC)
Page 1/3
Calibrating the LNG Tank Level Sensor Signal Conditioner (LSSC)
Special Tools and Materials Required:
•Westport Work Instruction INS-10011871 Draining the LNG Tank
•Westport Work Instruction INS-10012142 Purging the LNG Tank with Inert Gas.
•Westport Work Instruction INS-10011725 LNG Truck Refueling Instructions
•Westport Work Instruction INS-10011129 LNG Tank Service Kit – User Instructions
•Westport Work Instruction INS-10014508 Calibrating a “Canditioner” Type Fuel Level
Transducer.
•LNG Tank Service Kit P/N: 10010902
•LNG LSSC Calibration Tool P/N: 10010237
•Laptop computer with WCut software installed
•Male-to-male RS232 patch cable P/N: 10010898
•Vacuum cart (w/ pump) – capable of reaching a pressure of 20 mTorr
•Appropriate personal protective equipment (PPE)
Stage 1: In Preparation
1. Before beginning work, ensure that the vehicle:
a. is properly parked in an outdoor shop area with park brake on, engine off,
b. is not on sloped ground that can cause any depleting LNG to flow uncontrollably downhill,
c. is not directly over any sewage or storm drains that depleting LNG may flow into (natural
gas trapped in storm drains may form an explosive combustion mixture with air), and
d. is cordoned off with cones or equivalent warning signs to prevent other workers from
inadvertently approaching the vehicle while it is draining.
2. Confirm that the Fuel Level Transducer is LSSC type by referring to Stage 1, Step 1 of Westport
Work Instruction INS-10014508 Calibrating a “Canditioner” Type Fuel Level Transducer.
WARNING
Failure to properly drain the LNG tank(s) may lead to natural gas leakage and severe cryogenic
burns. Wear appropriate safety equipment at all times.
Stage 2: Calibration Low
3. Drain the LNG tank or tanks in accordance with Westport Work Instruction INS-10011871
Draining the LNG Tank
4. Ensure tank vent-to-STN, vent-to-ATM and liquid drain valves are all closed.
5. If the inner vessel of the tank has been exposed to atmospheric conditions for an extended
period of time, refer to “Stage 2: Evacuating Natural Gas from Tank” of Westport Work
Instruction INS-10012142 Purging the LNG Tank with Inert Gas to vacuum the inner tank vessel.
6. Connect the LNG LSSC Calibration Tool to the LNG tank harness service calibration port
(Figures 1 & 2).
7. Insert the key into the ignition and turn to the ON position. Do not start the truck.
8. Press the Calibrate LOW button once on the LNG LSSC Calibration Tool (Figure 1). The
calibration LED should flash once.
9. Wait at least 3 minutes before proceeding to the next step.

INS-10009982
Rev 02
Calibrating the LNG Tank Level Sensor Signal
Conditioner (LSSC)
Page 2/3
10. After the 3 minutes have elapsed, connect your laptop to the FDC controller inside the cab using
the RS232 patch cable. Launch WCut Software and use the standard “FDCIII-V2 DX30-
sv102.ini”. Once successfully connected, navigate to View 

Analog Input Tables 

Tank
Level #X where X denotes the tank you have just calibrated. This screen is shown in Figure 3.
Observe the variable Volt [V] and verify that it reads 0.5V +/- 0.1V. If this is not the case, repeat
Steps 7-9 until the voltage stabilizes to the correct value.
NOTE
If several (10 or more) attempts to calibrate low are unsuccessful, the tank may not be
suitable for use.
11. Disconnect the calibration tools, remove the key from the ignition and proceed to Stage 3.
CAUTION
Do not drive vehicle with LNG LSSC Calibration tool connected.
Stage 3: Calibration High
12. Fill the tank in accordance with Westport Work Instruction INS-10011725 LNG Truck Refueling
Instructions if filling from a fuelling station and Westport Work Instruction INS-10011129 LNG
Tank Service Kit – User Instructions if transferring a portion of fuel from a donor tank in order to
move truck to a fueling station.
NOTE
The tank may have risen to ambient temperature, making fuelling difficult. Fuelling may only take
place 5-10 gallons at a time before fuel transfer is automatically cutoff by the station.
13. Connect the LNG LSSC Calibration Tool to the LNG tank harness service calibration port
(Figures 1 & 2).
14. Insert the key into the ignition and turn to the ON position. Do not start the truck.
15. Press the Calibrate HIGH button once on the LNG LSSC Calibration Tool (Figure 1). The
calibration LED should flash once.
16. Wait at least 3 minutes before proceeding to the next step.
17. After the 3 minutes have elapsed, connect your laptop to the FDC controller inside the cab using
the RS232 patch cable. Launch WCut Software and use the standard “FDCIII-V2 DX30-
sv102.ini”. Once successfully connected, navigate to View 

Analog Input Tables 

Tank
Level #X where X denotes the tank you have just calibrated. This screen is shown in Figure 3.
Observe the variable Volt [V] and verify that it reads 4.5V +/- 0.1V. If this is not the case, repeat
Steps 14-16 until the voltage stabilizes to the correct value.
NOTE
If several (10 or more) attempts to calibrate high are unsuccessful, the tank may not be
suitable for use.
18. After calibrating LOW and HIGH, verify that the calibration LED is never solidly illuminated. This
indicates a calibration/system error. If this is the case, repeat the calibration procedure (Stages
2 and 3). If after repeating the procedure the LED is still solidly illuminated, the tank may not be
suitable for use.
19. Remove the calibration tools. Remove the key from the ignition.

INS-10009982
Rev 02
Calibrating the LNG Tank Level Sensor Signal
Conditioner (LSSC)
Page 3/3
Figure 1: LNG LSSC calibration tool
Figure 2: LNG tank harness
Figure 3: WCut Tank Level Screen
To service
calibration port