MT86/MT86HT Flow Meter OPERATION
Fluid Components International LLC 13
1. Record the true flow of the process media and the flow meter's milliamp output.
2. Turn the operating power OFF.
3. Connect the FC81 Field Calibrator to sensing point number 1. A set of precision decade boxes can be used instead of an FC81 Field
Calibrator. For the decade box wiring diagram refer to Figure 13. 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.
4. 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. Turn ON the operating power.
5. Adjust the FC81 Field Calibrator, or precision decade boxes, to give the milliamp output that was recorded in Step 1. Record the Delta
"R" that produced this output.
6. Remove jumpers J1 and J7. Add jumpers J2 and J8. This makes the span circuitry active.
7. With the FC81 Field Calibrator still at the Delta "R" from Step 5, adjust the span potentiometer, R16, to the new output as calculated
from the true flow measurement in Step 1.
8. From the Delta "R" table, put in the Delta "R" resistance value that represents the 4.0 milliamp output. Verify that the output has not
been affected by the span adjustment.
9. Turn OFF the operating power. Open switch SW1-3, and position the head-select switch SW2 to the number of sensing points in the
system. This puts the flow meter back in the operation mode.
10. Remove the FC81 Field Calibrator or decade boxes and connect sensing point number 1 to the input board.
Span and Zero Adjustment
As with the span adjustment, field data is also needed to perform adjustments. The information that is needed is the true flow rate and the
indicating milliamp output of the flow meter. Record and have the information available for FCI to review. The procedure is basically the
same as the span adjustment procedure. See Table 2 for jumper positions.
Table 2 – Jumper Configuration For Output Adjustment
Mode
J1 J2 J3* J4 J5 J6 J7 J8
Factory Set Span and
Zero
Yes No Yes No Yes No Yes No
Activated
No Yes Yes No Yes No No Yes
Span and Zero Activation No Yes Yes No No Yes No Yes
* J3 and J4 will always be in this position unless the factory has authorized option changes.
1. Repeat steps 1 through 5 listed above. Record the Delta "R" that was required to generate the milliamp output for both the low and
high flow rates.
2. Remove jumpers J1, J5 and J7. Add jumpers J2, J6 and J8, to make the span and zero circuitry active.
3. Adjust the FC81 Field Calibrator, or precision decade boxes, to the Delta "R" resistance that represents the low flow milliamp output of
Step 1.
4. Adjust the zero potentiometer, R17, on the control board to give the milliamp output that represents the calculated low flow.
5. Adjust the FC81 Field Calibrator, or precision decade boxes, to the Delta "R" resistance value that represents the high flow milliamp
output from Step 1.
6. Repeat Steps 3 through 5 until the correct milliamp output matches the Delta "R" for the high and low flows.
7. Disconnect the FC81 Field Calibrator or precision decade boxes and reconnect the sensing point to its original input board.
8. Return switch SW1-3 to the open position.
9. Set the head-selector, SW2, to the number of sensing points in the system. The flow meter can be reset to the factory set calibration
with the use of the original jumper setup. The originally installed jumpers are J1, J3, J5 and J7. The above span and zero adjustments
are not in effect when the flow meter is in the original configuration. The factory set calibrations are in control of the flow meter.
To Next Page
Loading...
