Sensor Temperature High Or Low; Troubleshooting When No Error Message Is Showing; Zero Current Is Too High - Emerson Rosemount MCL-220 Manual

2.
3.
4.
9.4.4

Sensor Temperature High or Low

The sensor RTD is most likely miswired.
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2.
3.
9.5 Troubleshooting when no error message is
showing
Problem
Zero current was accepted, but the current is outside the range -10 to 15 nA.
Error or warning message appears while zeroing the sensor (zero current is too high).
Zero current is unstable.
Sensor can be calibrated, but the current is less than about 250 nA/ppm at 25 °C.
Process readings are erratic.
Readings drift.
Sensor does not respond to changes in monochloramine level.
9.5.1

Zero current is too high.

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2.
Instruction Manual
Disconnect the white and white/red sense and return leads and measure the
resistance between them.
It should be less than 1 Ω. See
sensor is still usable.
Use a wire jumper to connect the sense and return terminals on the sensor terminal
strip.
The temperature reading will no longer be corrected for the lead resistance, nor will
the transmitter be able to compensate for changes in ambient temperature. The
error could be several °C or more.
Replace the sensor.
Check wiring connections.
Check resistance between RTD in and return leads.
The resistance should be close to the values given in
Replace the sensor.
Is the sensor properly wired to the transmitter? See
Is the zero solution monochloramine free? Take a sample of the solution and test it
for monochloramine level. The concentration should be less than about 0.02 ppm.
Figure 9-4. Even though the sense line is open, the
Section
Section
Troubleshooting
9.8.2.
See Section
Section 9.5.1
Section 9.5.1
Section 9.5.2
Section 9.5.3
Section 9.5.4
Section 9.5.5
Section 9.5.6
4.1.3.
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