Emerson Process Management 3081 pH/ORP instruction manual Ok?

MODEL 3081 pH/ORP	SECTION 12.0
	TROUBLESHOOTING

pH measurement problem

Perform buffer calibration (outside of the process)

Refer to Section 7.5

Buffer calibration	YES	Likely Process Problem
OK?		or Ground Loop:

NO

Place transmitter internal pream-

plifier switch in proper position.

NO

Is internal preamplifier switch in transmitter in correct position? See Figure 2-2.

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)

YES

Simulate pH directly into the trans-

mitter. Refer to Section 12.8.2.

Transmitter problem.	NO	Analyzer test OK?	YES	Likely Sensor Problem:
Replace Analog/CPU board
stack (PN 23574-02).				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.

FIGURE 12-6. Troubleshooting Flow Chart / Preamplifier in Transmitter or Built into Sensor

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