Fluid Components International MT86_MT86HT Manual Operation - Manual (Page 4)

FLUID COMPONENTS INTL CHAPTER 3 - OPERATION
Models MT86, MT86HT 3 - 4 Doc. No. 003162 Rev. F
Generating New Delta "R" Tables
Using the FC81 Calibrator
1. Obtain the correct FC81 Field Calibrator for the MT86 or MT86HT Flowmeter:
Model FC81-8 is used for the MT86 with 1000 ohm flow element sensing point RTDs.
Model FC81-7 is used for the MT86HT with 100 ohm flow element sensing point RTDs.
2. Turn the operating power OFF and then disconnect the flow element cable from the terminal block TS1 on the
input board.
3. Connect the FC81 Field Calibrator cable to terminal block TS1 (sensing point 1). Also, connect the cable to one
of the output module connectors P7, P8, P9, or P11 that is located on the control board. A set of precision
decade boxes can be used instead of the FC81 Field Calibrator. Use the wiring diagram in Figure 5-4 to connect
the decade boxes.
4. On the control board, monitor the voltage (VDC) across TP10 (-) and TP9 (+) and from TP5 (-) to J8 (+).
5. On the output board, monitor the output signal (4 to 20 mA, 10 to 50 mA, 0 to 5 VDC, etc.,) with a DMM.
6. 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.
7. Set the head-select switch SW2 to the number one (1) position.
8. Verify that switch SW4 is in the OP (OPerate) position.
9. Turn the operating power ON and let the system stabilize for a minimum of 5 minutes.
10. Set the FC81 Field Calibrator to the "READ VOLTS" position and remove the "ADD OHMS" by setting both
buttons to the OUT position. The voltage on the FC81 Field Calibrator can now be read. This is the same
voltage that is across TP5 (-) and J8 (+). Adjust the voltages by turning the "OHMS ADJUST" potentiometer.
11. On a blank Delta "R" sheet, write down the serial number of the flowmeter and the flow element serial number.
Blank Delta "R" sheets are obtained from FCI Customer Service.
12. Adjust the "OHMS ADJUST" potentiometer to give an output of 4.00 mA, which is zero volts on the FC81
Field Calibrator.
13. On the Delta "R" sheet record the TP9 to TP10 voltage, the TP5 to J8 voltage (which is the same voltage that
the FC81 Field Calibrator displays), the MILLIAMP OUTPUT and the LOCAL DISPLAY reading, if
applicable.
14. Depress the "SET OHMS" button on the FC81 Field Calibrator to display the new Delta "R" value for the
4.00 mA output. With the FC81 Field Calibrator "SET OHMS" Button depressed the flowmeter does not read
the Delta "R" values. The DMMs will give open circuit or random values.
15. Record the new Delta "R" on the data sheet. For Model FC81-8 Field Calibrator the displayed Delta "R" value
is divided by 10 . For Model FC81-7 there is no division necessary.
16. Set the calibrator to "READ VOLTS" and then adjust the "OHMS ADJUST" potentiometer to give the
following outputs: 5.00, 6.00, 8.00, 12.00, 16.00, and 20.00 mA and repeat Steps 13 through 16 for each.
17. Turn the operating power OFF. Then transfer the FC81 Field Calibrator cable to terminal block TS2.
18. Turn the operating power ON. Allow one minute for the flowmeter to stabilize.
19. Set the calibrator to "Read Volts" and repeat Steps 10 through 16. Remember to set the head-select switch,
SW2, to the number 2 position for sensing point number 2.
20. Repeat this procedure for all the remaining sensing points in the system. Remember to set the head-select switch
SW2 to the sensing point number that a new Delta "R" table is generated for.
21. When the Delta "R" table has been completed for the whole system, set the head-select switch to the total
number of sensing points in the system. For example, a flowmeter that has 4 sensing points should have the
head-select switch SW2 in position 4.
22. Open switch SW1-3, which places the flow transmitter in the automatic mode. This puts the flowmeter back into
the operation mode.