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• How do I change the battery for the TFC-01?
• What if after changing new battery and the set does not work ?
• Why doesn't the probe lowers into the tank ?
• What happens when the Display: TEMP ERROR?
• What is the working principle?
• Does the TFC-01 require periodical calibration?

How do I change the TFC-01 battery?

The battery should be changed only in a gas-free environment, or SAFE atmosphere. Example: Cargo Control Room, Engine Room. The TFC-01 has a low battery indicator, the rectangle sign will flash if the battery voltage drops to 7.0 Volts or less. There is a voltage sensor set at the display PCB.

Procedure to change battery:

1. Remove the Cover ring. Four hex screws of 4 mm head.
2. Place the screws and spring washers into a containing tray, so as not to lose them.
3. Pull out the Display plate together with the Printed Circuit Board (PCB).
4. Flip it to one side, with the wires hanging on to it.
5. Pull out the flat battery (located at the bottom, above the buzzer. Do not pull it by the cables, but grip the battery top with finger and thumb.
6. Remove the battery connector cap, and test battery with Voltmeter to confirm that it is flat.
7. Replace new battery and plug in the connector cap.
8. Put back the PCB and face plate, aligning the four screw holes.
9. Check if the gasket is in place.
10. Place the spring washers first, then the hex screws and screw them back diagonally.
11.  Switch on the set to test.

  LOW BAT  - click on this to view a movie

What if after changing the battery and the set does not work ?

The set is a micro-controller system, which runs a self-test routine when ever the set is switched on. The time for this test run is less than five seconds.

But if the display shows a blank, no display at all, then remove the PCB plate and check the voltage of the new battery. If this battery is about 9.0 Volts, plus minus 0.5 volts, means the battery is good.

1. Pull out the battery connector, and push one end in, leaving the other end open.
2. Use an ampere meter to bridge the two open connections. (Beware of the polarity, positive to the positive part of the battery, and negative to the connector.
3. Switch on the set and see if there is any current flowing through the meter.
4. The negative pole of the battery is connected to the ground, or the body of the TFC-01 and the positive pole to the switch.
5. Try to jump the switch by linking positive of the battery to outlet of the toggle switch.
6. If this works, the fault lies in the switch.
7. If this does not work, the possible fault is the fuse was blown.
8. To replace the fuse, go to Fuse Replacement Procedure.
9. To confirm the fuse blown, use a OHM meter to test the two points of the fuse. Good fuse should read zero or near zero Ohm.

Why doesn't  the probe lowers into the tank ?

In the storage position, the rewind reel is locked and cannot be turned either way. Check if this reel lock handle is released.

The procedure to commence tank gauging is:

1. Place the barrel of the PMS on to the Deck Valve.
2. Screw the cap nut on to the Deck Valve, turning clockwise direction.
3. Clamp the Grounding clip on to the bare metal part of the valve flange (This is to prevent accidental flash caused by static electrical charges built on the tape insulations.)
4. Open the Deck Valve by turning the handle 90 Degrees to parallel with the valve body and flanges.
5. Release the Tape Wiper by turning the knob to 12 o'clock position. (Do not turn beyond this point  in anti-clockwise, you may kink the tape if you do.)
6. The tape and probe should be free to go into the tank.
7. If it does not go into the tank, and if the winding reel is sticky and tight, the problem is most likely to be with the Tape Plates being jammed.
8. Go to procedure to check the Tape Plates.

What happens when the display: TEMP ERROR?

The Electronic UTI Measurement system works on the principle of digital communication between the probe and the display board. The speed is at 4 MHz, or at one million instructions a second. At the  initial power-on startup, the system goes into a self-checking mode for five seconds. Should the system detect abnormality in the communication link, the temperature range, or a malfunction of the ultrasonic or conductivity sensor, or any break or short circuit  in the communication link or power supply, it will display "TEMP ERROR".

The most common fault is the tape conductor broken, and this accounts to more than 70% of the faults. However, one should verify the tape break by the following steps:

1. Unwind the tape to about 30 cm length, remove the Storage Barrel.
2. Remove the probe sensor from the tape head connector.
3. Remove the Face Plate and Display PCB and remove the RED, BLACK, and YELLOW wires of the tape shield connector from the Display PCB connectors. Mark the wires before removing, so you can fix them back the same way.
4. Use an Ohm meter and check the connection between the probe and Display PCB. Red to red, yellow to yellow and black to black.
5.  If any of these wires shows an open circuit, this means the tape is broken and needs replacement.
6. Put back the three wires to the PCB connectors and fix back the face cover as in the battery replacement routine.
7. Unwind the tape, roll it up neatly and coil it around as you unwind slowly, until the end of the tape.
8. Flip the tape body over to the back side and remove the four screws of the cover.
9. Remove the four screws at the hub core and take out the cover and the top tape plate.
10. Check to see if the insulations on the three cables are good.
11. Remove the two tape mounting bracket screws and the bracket. Note its orientation, as you have to put it back later.
12. Cut the heat shrink tube insulation and with soldering iron, remove the solder connections of the red, yellow and black wires.
13. Coil the remaining tape and take it out of the chamber. Please take note: the tape is strung through the Cleaning Wiper, below the reading bar and over the pulley and round the core hub.
14. Clean up the Graduated Tape Holder, make sure the slit opening is clear from silicone sealant.  The PMS is ready for the replacement of new tape.

What is the working principle?

TEMPERATURE

The most reliable and accurate method to measure temperature is by Platinum resistance Thermometer (PRT) sensor. The TFC-Portable Measuring System uses the 3-wire PT100 sensor.

The  PRT thermometer yields a linear output of resistance versus temperature curve which has three standards output of resistance. TFC uses the Class B standard of 0.3 Ohms per Degree Celsius.

ULLAGE SENSOR

The measurement of oil or oil like liquid which is not electrically conductive,  and by contact  is consistent by sonic or ultrasonic conduit of the liquid. Sound travels through the air at a speed of about 300 mps, and through liquid at about 1,200 mps. Different liquid has different velocity and the sensor has to be designed to take in a broad spectrum of liquids, such as Alcohol, Phenol, and lubricating oil.

Two piezoelectric transducers are placed in an arch, directly facing each other. One transmits the ultrasonic vibration, while the other receives the waves from the transmitter through the liquid media. As the probe touches the oil level, it forms a bridge from transmitter to receiver and the signal is triggered to flag a micro-controller inside the probe. This digital signal is sent via a RS232 communication bus to the Display PCB at about 30 meters away.

INTERFACE SENSOR

Water is a conductor of electricity, and two stainless steel electrodes are used for the interface mode. Two electrodes of high grade stainless steel are used for the interface measurement.

The moment the electrodes touch the water phase, an electrical current is connected from one electrode to another. This electrical current triggers a switch and it tells a remote display unit that water is sensed.

 

Does the TFC-01 require periodical calibration?

Tijit Pte Ltd holds about $50,000 worth of spare parts stocks and equipments for the Tankech Electronic Tape alone.

TFC-01 uses Platinum Resistance Thermometer, PT100Ω and actually does not require periodical calibration, but for the peace of mind of the ship operators, we do cater for temperature calibration with precision temperature controlled water bath.