ST100A Series Flow Meter TROUBLESHOOTING
Fluid Components International LLC 99
Constant Power Configuration Troubleshooting
Equipment List
● 250 Ω 0.01% resistor
● 2 digital multimeters (DMM)
● Delta R Calibration Data Sheet (serial number specific by instrument and group)
● FES-200 flow element simulator
● FES-200 interface cable for ST80/ST80L (022610-xx)
Alternative to FES-200:
● 2 ea. Precision Decade Resistance Box, 0.1% (1 kΩ large step, 0.01 Ω small step)
Delta R Check for Constant Power Configured Units
If the flow meter’s parameters have been changed, calibrations may be inaccurate or factory authorized changes
have been made. Consult a factory service representative.
Each flow meter configured at the factory for Constant Power (refer to Configuring for AST™ or Constant Power Measurement Methods,
page 46) is provided with a Delta R data sheet that lists the differential resistance values that correlate to the flow meter’s calibration.
Resistance substitution instruments like the FES-200 can be used to check instrument calibration and verify correct operation of the flow
transmitter using the Delta R data sheet.
To verify the transmitter is working properly, the sensor head must be disconnected and precision resistance (Delta R) values from the
FES-200 are substituted. Then by measuring the transmitter output and display it can be determined whether the transmitter is still within
factory specification.
Delta R Check
1. Verify the Delta R data sheet has the same serial number and group number as the flow meter calibration that is being verified.
2. Turn transmitter power OFF.
3. Disconnect a flow element sensor from the ST100A Series transmitter (TB1/TB2) and connect the FES-200 cable connector in its
place. See Figure 72. Precision decade boxes can be used in place of the FES-200. See Figure 73 for decade box wiring.
4. Connect a DMM to the transmitter 4-20 mA output by either method A or B as shown in Figure 71 below.
a. To read 1 to 5 volts, disconnect both output loop wires and connect a precision 250
To Next Page
Loading...
Need help?
General
