Sierra INNOVA-MASS 241-VTP - Manual (Page 62)

Series 24-HP Instruction Manual Chapter 4 Troubleshooting & Repair
IM-24-HP 4-7
setting. During flow, view the f and fi values in the first col-
umn of the hidden diagnostics. The fi value should be approx-
imately 10-20 % higher than the f value. If you raise the Ck
setting in the Calibration Menu, then the fi value will increase.
The fi is a low pass filter, so by increasing it or lowering it, you
can alter the range of frequencies that the meter will accept. If
the vortex signal is strong, the fi value will increase to a large
number – this is correct. Note: at high frequencies, the display
may not be able to display all the digits of the fi value (for ex-
ample, 114 may be displayed and the actual value is 1140).
Symptom: No Output
1. For remote mounted electronics, carefully check all the wiring
connections in the remote mount junction box. There are 18
connections that must be correct, verify each color (black and
red), shield, and wire number.
2. Turn on the pressure and temperature display in the Display
Menu and verify that the pressure and temperature are correct.
3. Using ESD precautions and hazardous area precautions, re-
move the electronics enclosure window cover. Disconnect the
vortex sensor from the analog board (the analog board is the
first board below the microprocessor (display) board. Measure
the resistance from each outside pin to the meter ground - each
should be open. Measure the resistance from the center pin to
the meter ground – this should be grounded to the meter. With
the sensor still disconnected, go to the first column of the hid-
den diagnostics and display the vortex shedding frequency, f.
Hold a finger on the three exposed pins on the analog board.
The meter should read electrical noise, 60 Hz for example. If
all readings are correct, re-install vortex sensor wires.
4. Verify all meter configuration and troubleshooting steps pre-
viously described. There are many possible causes of this
problem, consult factory if necessary.
Symptom: Meter Displays Temperature Fault
1. For remote mounted electronics, carefully check all the wiring
connections in the remote mount junction box. There are 18
connections that must be correct, verify each color (black and
red), shield, and wire number.
2. Go to the first column of the hidden diagnostics and check the
resistance of the rtd1. It should be about 1080 ohms at room
temperature.