MT86/MT86HT Flow Meter
OPERATION
Fluid Components International LLC
11
Figure 7 – Zero Based Calibration
The output signal is easier to interpolate when milliamp output is interfaced with control room 0 to 100% gauges; 50% of the signal will
correspond to 50% of the maximum flow rate.
Zero-based flow meters have less signal to resolve over full scale. A zero-based flow meter with a turndown ratio of 10:1 will have 10%
less output range to resolve flow (5.6 mA to 20 mA instead of 4 mA to 20 mA in a non-zero-based flow meter).
Zero-based calibration is the factory default.
Delta "R" Table
The Delta R Sheet (found in the plastic page protector in the back of this manual) contains the actual data chart for the flow meter. The
Delta R portion of this sheet relates actual laboratory calibration measurement points of the differences (delta) between the reference and
active RTDs at certain flow rates.
These parameters are used at the factory to determine the linearization coefficients (parameters) over the flow range in question to correct
for non-linearity. The corresponding current and voltage output readings are also shown (again at factory default settings), changes to
range and zero will only affect the output signals. Flow versus Delta R relationship is fixed for a given set of flow elements; do not change
the coefficients except in special circumstances as the overall accuracy of the system is tied to these numbers. Call Customer Service if
there is a problem in this area.
The Calibration Table is a printout (at factory default settings for zero and offset) of the relationship of displayed mass flow readings related
to the current output when calculated over the entire flow range using the fitting equation and its respective coefficients.
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
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.
C00114-3-2
ZERO BASED
ZERO
OUTPUT
(mA)
MIN
FLOW
50% FULL SCALE
NON ZERO BASED
FLOW (SFPS)
0
0.0
4.0
8.0
12
16
20
10
20
30
40
50
60
Summary of Contents for MT86
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Page 19: ...MT86 MT86HT Flow Meter OPERATION Fluid Components International LLC 15 Figure 9 A D Data Sheet...
Page 40: ...APPENDIX A DRAWINGS MT86 MT86HT Flow Meter 36 Fluid Components International LLC C01156 1 1...
Page 47: ...MT86 MT86HT Flow Meter APPENDIX C CUSTOMER SERVICE Fluid Components International LLC 43...
Page 48: ...APPENDIX C CUSTOMER SERVICE MT86 MT86HT Flow Meter 44 Fluid Components International LLC...
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