Emerson B-106-300NH Cell Problem, Cell Troubleshooting Problem, Status is LowO2 Cell mV = -127 mV

World Class 3000

Instruction Manual

IB-106-300NH Rev. 4.2 July 2002

6-5 CELL PROBLEM

For cell troubleshooting, as in heater problems, you should allow at least 30 minutes for operat- ing temperature to stabilize. After this warmup period, observe the system status and cell volt- age. If the heater is working, troubleshoot the cell. If the heater is not working, refer to Heater Problem, paragraph 6-4.

•The status line may read: Low O2, Hi O2, CalEr, ResHi.

•Access voltage values in the proper menu. Use the DIAGNOSTIC DATA sub-menu of the PROBE DATA menu.

•The displayed O2 value will read 0% to 99%.

•It may be helpful to observe the calibration status and parameters from the last calibra- tion: Slope, Constant, and Cell Resistance. In the CALIBRATE menu, VIEW CON- STANTS shows previous calibration values, and CALIBRATION STATUS shows the latest values. If these values appear out of range, perform a calibration before trouble- shooting the cell.

Refer to Table 6-3to troubleshoot cell related problems.

Table 6-3. Cell Troubleshooting

Problem

Cause

Corrective Action

Status is LowO2.

Cell mV = -127 mV.

1.	Faulty cell connection or open. If the cell circuit is open, the cell output will show about -127 mV.
	Check cable connection between the probe and the electronics. Check that the probe spring
	presses the contact pad firmly onto the cell. Repair or replace faulty wires, spring, or connectors.
2.	Electronics fault. Cell output is good, and the input to the electronics is good.	6
	Check the electronics package. In an IFT, replace the microprocessor or interface board as

needed. In a CRE, replace the DPI board if needed.

Status is ResHi or CalEr.

Cell mV = -20 to 120 mV (normal).

1. Test gas flow not 5 scfh (2.4 L/min).

Check test gas flow and related piping. Rotameter should show 5 scfh. Adjust needle valve for correct flow rate.

2. Incorrect test gas.

Confirm labels on test gas bottles are correct. Confirm High Gas and Low Gas values agree with labels on test gas bottles. (Refer to menu map — SETUP-CALIBRATION, High Gas, Low Gas.) Check all ports, cylinders, and gas lines for proper hookup. Change piping if necessary. Label pipes for reference.

Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 6-5