ENMET ISA-44-2OD User Manual

Page 22

ENMET Corporation

ISA-44-2-OD

5.2.2 Oxygen Channel # 2

This procedure is given in reference to an S-2 cell, which is ENMET P/N 67013-008 as furnished as a replacement cell.

ATERIALS

digital voltmeter

small screwdriver

ROCEDURE

1. Turn

OPERATION

switch to H

ORN

position.

2. Null Adjust

a. Disconnect the oxygen cell from the circuit by disconnecting leads at TB3-8 (+) (terminal block 3-position 8)

and/or TB3-9 (-). Removing one lead is sufficient to break the circuit. See Figure 3.

b. Connect negative (-) voltmeter lead to TP-1 (test point one) and positive (+) voltmeter lead to TP-2 in the oxygen

circuit. These are in the lower right hand corner of the printed circuit board.

c. Adjust the Null Adjust potentiometer to read 0.00 V

between TP-1 and TP-2.

3. Low Level Set:

a. Reconnect the oxygen cell to TB3-9(-) and TB3-8(+).

b. Make sure the oxygen cell is properly connected by measuring the voltage between TB3-9 and TB3-8. Voltage

should read between .043 and .09 V

. Allow oxygen cell to stabilize for 15 minutes.

c. Connect negative lead of voltmeter to TP-1 and positive lead to TP-3 in the oxygen circuit.

d. Adjust the Low Level Set potentiometer to read .766 V

4. Full Scale Adjust:

a. Leave negative lead of voltmeter at TP-1 and connect positive lead of voltmeter to TP-2 in oxygen circuit.

b. Adjust oxygen gain potentiometer (on front panel of unit) so the voltmeter reads 1.24 V

c. Adjust Meter Full Scale Adjust potentiometer on circuit board so the meter on the front panel reads full scale

(26%). Adjust this potentiometer cw to increase, ccw to decrease meter reading.

d. Verify that the oxygen alarm comes on at the predetermined alarm point (19.5%) on the meter. If it does not,

repeat steps a. and b. in this Section. If the oxygen alarm still does not come on, repeat the entire recalibration
procedure checking terminal connections, testpoints and voltage settings very carefully. Contact your local
Authorized ENMET Service Center if problems persist.

e. Adjust and leave the oxygen gain potentiometer at a meter reading of 20.9% (setpoint).

5. The oxygen cell calibration is now complete. Turn the operation switch to O

PERATE