Emerson Process Management 8732 Transmitter Troubleshooting, Advanced Troubleshooting-Rosemount

Reference Manual

00809-0100-4663, Rev BA January 2010

Rosemount 8732

TRANSMITTER

TROUBLESHOOTING

Table 6-4. Advanced Troubleshooting–Rosemount 8732

Symptom	Potential Cause		Corrective Action
Does not appear to be within	Transmitter, control system, or other	Check all configuration variables for the transmitter, sensor,
rated accuracy	receiving device not configured	communicator, and/or control system
	properly	Check these other transmitter settings:
		•Sensor calibration number
		•Units
		•Line size
	Electrode Coating	Use bulletnose electrodes;
		Downsize sensor to increase flow rate above 3 ft/s;
		Periodically clean sensor
	Air in line	Move the sensor to another location in the process line to
		ensure that it is full under all conditions.
	Moisture problem	Perform the sensor Tests A, B, C, and D
		(see Table 6-5 on page 6-8)
	Improper wiring	If electrode shield and signal wires are switched, flow indication
		will be about half of what is expected. Check wiring diagrams for
		your application.
	Flow rate is below 1 ft/s	See accuracy specification for specific transmitter and sensor
	(specification issue)
	Auto zero was not performed when the	Set the coil drive frequency to 37 Hz, verify the sensor is full,
	coil drive frequency was changed from	verify there is no flow, and perform the auto zero function.
	5 Hz to 37 Hz
	Sensor failure–Shorted electrode	Perform the sensor Tests C and D
		(see Table 6-5 on page 6-8)
	Sensor failure–Shorted or open coil	Perform the sensor Tests A and B
		(see Table 6-5 on page 6-8)
	Transmitter failure	Verify transmitter operation with an 8714 Calibration Standard or
		replace the electronic board
Noisy Process	Chemical additives upstream of	Complete the Noisy Process Basic procedure. Move injection
	magnetic flowmeter	point downstream of magnetic flowmeter, or move magnetic
		flowmeter.
	Sludge flows–Mining/Coal/	Decrease flow rate below 10 ft/s
	Sand/Slurries (other slurries with
	hard particles)
	Styrofoam or other insulating particles	Complete the Noisy Process Basic procedure;
	in process	Consult factory
	Electrode coating	Use replaceable electrodes in Rosemount 8705.
		Use a smaller sensor to increase flow rate above 3 ft/s.
		Periodically clean sensor.
	Air in line	Move the sensor to another location in the process line to
		ensure that it is full under all conditions.
	Low conductivity fluids (below 10	•	Trim electrode and coil wires – see “Conduit Cables” on
	microsiemens/cm)		page 2-6
		• Keep flow rate below 3 FPS
		•	Integral mount transmitter
		•	Use 8712-0752-1,3 cable
		• Use N0 approval sensor
	Advanced Troubleshooting continued on next page

6-5