Instruction manual

12.0 TROUBLESHOOTING SM425 INSTRUCTION MANUAL

The operating temperature range of the Model ZO21D Detector is -10°C to 80°C (except for the high-

temperature detector ZO21D-H). A cold junction temperature alarm for this analyzer is not generated

until the temperature exceeds 155°C. If a Model ZO21D Detector is used, the ambient temperature of the

terminal block must be controlled.

1: Thermocouple Voltage Alarm

ater temperature failure) also

occurs. An Alarm 11 can be caused by any of the following:

ween the converter and the detector is open, or the cable

< Troubleshooting and Corrective Actions >

12.2.2.6 Alarm 1

This alarm is generated when the emf (voltage) of the thermocouple is not in the -5 mV to 42.1 mV (about

-170°C to 1020°C) range. Whenever Alarm 11 is generated, Error-2 (he

1. The heater thermocouple signal wire bet

is not securely connected to the terminal

2. The positive and negative poles of the heater thermocouple signal wiring are shorted out in the

wiring extension or at the connection terminals.

3. The thermocouple at the detector heater assembly failed.

4. An electronic failure inside the converter occurred.

1. Power off the converter.

2. Disconnect the wiring from terminals 3 and 4 of the detector and measure the resistance between

these wires. The resistance should be 5 Ω or less. A higher resistance indicates the

thermocouple requires replacement (refer to Section 1.59.3, “Replacement of the Heater Unit”).

• Measure the thermocouple resistance after the difference between the detector tip temperature and

0°C or less. Accurate measurement cannot be made with a high

thermocouple temperature.

ambient temperature falls to 5

3. If the thermocouple resistance is normal, check for open or shorted wires. Verify the wiring cable

wiring testing passes. Contact the

12.2.2.7 Alarm 13: Battery Low Alarm

An internal battery is used as backup for the analyzer clock. After this alarm occurs, removing power from

the instrument may cause the clock to stop. Stored parameters are not affected. The internal clock is

is securely connected to the terminals. Measure the resistance between the converter and the

detector. It must be 10Ω or less.

4. An electronic circuit failure is likely if the thermocouple and

service personnel at Teledyne Monitor Labs.

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