Emerson Process Management 3081 pH/ORP instruction manual Yes

MODEL 3081 pH/ORP	SECTION 12.0
	TROUBLESHOOTING

	Process 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:
			1. Measure pH of a grab sample in
	NO		a beaker. If pH is correct, then
			the process is OK.
			2. Resolve the ground loop; insu-
	Is transmitter		late shield wires from grounded
NO			metal. See Section 12.5.8
	preamplifier switch in		3. Ground un-grounded processes:
Put transmitter preamplifier switch	junction box position?
(S-1) into junction box position.	(see Figure 2-2)		(example: all plastic piping)

YES

Simulate pH through the pream- plifier and transmitter. Refer to Section 12.8.3.

Simulate pH directly into			NO			Preamplifier and trans-		YES	Likely Sensor Problem:
transmitter: bypass the pre-
							mitter test OK?
amplifier. See Section 12.8.2.									1.	Verify sensor is compatible with
										the analyzer. Must have PT100,
										PT1000, or 3K Balco RTD. Verify
				YES						RTD jumpers and temperature
Transmitter test OK?					Preamp or Wiring problem:					parameter programming.
									2.	Check RTD. If bad or wrong, use
					1.		Check wiring.			manual temperature compensa-
					2.		Replace preamplifier.			tion (see Section 8.5).
	NO	Transmitter problem:							2.	Clean sensor & re-test it.
									3.	If problem persists, rebuild or
		1. Replace Analog/CPU board stack
		(PN 23574-02)								replace the sensor.

FIGURE 12-5. Troubleshooting Flow Chart / Preamplifier in Sensor-Mounted Junction Box

or Remote Junction Box

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