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MODEL 3081 pH/ORP SECTION 12.0
TROUBLESHOOTING
Perform buffer calibration
(outside of the process)
Refer to Section 7.5
Buffer calibration
OK?
Analyzer test OK?
Place transmitter internal pream-
plifier switch in proper position.
Likely Process Problem
or Ground Loop:
1. Measure pH of a grab sample in
a beaker. If pH is correct, then
the process is OK.
2. Resolve the ground loop; insu-
late shield wires from grounded
metal. See Section 12.5.8
3. Ground un-grounded processes:
(example: all plastic piping)
Likely Sensor Problem:
1. Verify sensor is compatible with
the analyzer. Must have PT100,
PT1000, or 3K Balco RTD. Verify
RTD jumpers and temperature
parameter programming.
2. Check RTD. If bad or wrong, use
manual temperature compensa-
tion (see Section 8.5).
2. Clean sensor & re-test it.
3. If problem persists, rebuild or
replace the sensor.
Transmitter problem.
Replace Analog/CPU board
stack (PN 23574-02).
Simulate pH directly into the trans-
mitter. Refer to Section 12.8.2.
YES
YES
YES
NO
NO
NO
Is internal preamplifier
switch in transmitter in
correct position? See
Figure 2-2.
pH measurement problem
FIGURE 12-6. Troubleshooting Flow Chart / Preamplifier in Transmitter or Built into Sensor