FCI MT86, Installation, Operation & Maintenance Manual

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TROUBLESHOOTING MT86/MT86HT Flow Meter
28 Fluid Components International LLC
Ohms Adjust
On the right side of the front panel is a 10-turn potentiometer that is used to input the desired Delta "R" resistance values.
Add Ohms Switch
A Delta "R" value may be more than the maximum value of the ohms adjust potentiometer. If this happens, there is another push-button
switch on the right hand side of the panel that adds a fixed resistance to the displayed value.
If an MT86HT has a Delta "R" value greater than 10 ohms, use the add ohm switch.
If an MT86 has a Delta "R" value greater than 100 ohms, use the add ohm switch.
The display's readout does not show the ohms added. The ohms added MUST be added to the displayed resistance for determination of
the actual applied Delta "R". The ohms added and the displayed value MUST be combined to get the actual Delta "R" value.
Connector Receptacle
On the rear panel of the field calibrator is an AMP brand receptacle with round post connectors for the test cable.
FC81 Field Calibrator Operating Procedure
1. This procedure adjusts the Delta "R" values to give a recorded output signal. Then Delta "R" value reading is compared to the
recorded value. This procedure verifies the proper operation of the flow transmitter. Be sure to have the correct Delta "R" data sheet
by checking the serial number of the flow element and the serial number on the sheet.
2. Turn OFF the power to the flow meter. Record where the jumpers are on the control board before the testing begins. Remove the
connector from the input board's terminal block TS1. Remove jumpers J2 and J8 if they are present on the control board. If jumpers
J1 and J3 are not installed, then install them at this time.
3. Connect the cable from the FC81 field calibrator to the input board terminal block TS1. Connect the ribbon cable to any available
output module connector; P7, P8, P9 or P11.
4. Turn the power ON and allow 5 minutes for the control circuits to stabilize.
5. Close switch SW1-3 that puts the flow transmitter in the manual mode; this enables the head-select switch SW2 to select and monitor
one sensing point. Select the sensing point to be tested with the head-select switch, SW2.
6. With the FC81 field calibrator function switch in the out position, to readout the output signal, turn the ohms adjust potentiometer to
give a recorded voltage out.
7. Push the function switch in and read the Delta "R" (in ohms) that produced the recorded voltage out reading. Record the measured
signal.
8. Repeat Steps 6 and 7 for all values listed on the Delta "R" data sheet. Verify the Delta "R" data repeats the recorded value within
1.25% of full scale.
9. If all the measurements are within the limits, turn the power OFF and move the FC81 field calibrator to the next sensing point to be
verified. Repeat the procedure for the next sensing point to be verified. When the procedure is finished, open switch SW1-3 and
position the head-select switch SW2 to the number of sensing points in the flow meter.
Switch Point Calibration Procedure
The flow meter has field adjustable switch point relays. Relay energization is changed by moving a plug-jumper on the circuit board. Each
switch point circuit has an LED which indicates the relative condition of the flow signal. In all cases, the LED is illuminated when the flow
signal is below the set point. Jumper positions J1 and J2 select the energization state of the switch point relay number 1 (K1). With J1 in
place, the relay is energized when the signal is above the set point. With J2 in place, the relay is energized when the signal is below the
set point.
1. Connect an appropriate meter to TP13 and TP5 on the main circuit board.
2. Set the calibration switch (SW4) on the main circuit board to the CAL position. See
Figure 12 .
3. Adjust the CAL potentiometer (R23) on the main circuit board until the meter readout shows the desired switch point signal level
(select the desired signal level form the calibration table).
4. If the red LED is lit, turn potentiometer R3 counterclockwise until the LED turns off. With the LED off, turn R3 very slowly clockwise,
just until the LED turns on, then stop.
5. Vary the set point by turning the potentiometer (R23) clockwise and counterclockwise through the set point to see that the relay
changes at the desired point.