Yokogawa Single Channel Oxygen Analyzer System ZR22/ZR402 - Manual (Page 194)

IM 11M12A01-03E 12-10
12.2.2.5 Alarm 9: Exhaust Gas Temperature Alarm
When “mA-input” is selected in the Exhaust gas setup display, this alarm occurs if the
exhaust gas temperature exceeds the set alarm values.
The following are probable causes:
(1) The temperature transmitter output range does not meet the analyzer Exhaust gas
setup (if this alarm occurs when the equipment starts up).
(2) Thermocouple(s) connected to the temperature transmitter may be defective (discon-
nected).
(3) Temperature transmitter may be defective.
(4) Exhaust gas temperature may exceed the set alarm value.
<Locating cause of failure, and countermeasures>
(1) Check that the temperature transmitter output temperatures at 4 and 20 mA meet the
temperatures at 4 mA and 20 mA set with this equipment.
(2) Check that an actual exhaust gas is normal.
Press the detailed data display key to display and check that the exhaust gas temperature
in the displayed detailed data is normal. If this value is outside the temperature
transmitter’s normal output, the thermocouple(s) connected to the temperature transmit-
ter may be damaged (disconnected). See the applicable temperature transmitter instruc-
tion manual for solving problems.
12.2.2.6 Alarm 10: Cold Junction Temperature Alarm
This alarm is generated when the temperature of the cold junction located at the
terminal block of the detector falls below -25
Њ C or exceeds 155Њ C. Check the following:
Display “C.J.Temperature” in the detailed data display. If “C.J.Temperature” is
indicated as 200
Њ C or -50Њ C, the following can be considered.
(1) Breakage of the cold junction signal wires between the converter and the detector, or
the cable is not securely connected to the connecting terminals.
(2) The positive and negative poles of the cold junction signal wiring are shorted out in
the wiring extension or at the connection terminals.
(3) A failure of the cold junction temperature sensor located at the detector terminal
block occurred.
(4) A failure of the electrical circuits inside the converter occurred.
If “C.J.Temperature” exceeds 150
Њ C or falls below -20Њ C, the following can be
considered.
(1) The temperature of the detector terminal block is out of the operating temperature
range (-20
Њ C to 150Њ C).
(2) A failure of the cold junction temperature sensor located at the detector terminal
block occurred.
(3) A failure of the electrical circuits inside the converter occurred.
<Locating cause of failure, and countermeasures>
Before proceeding to the following troubleshooting procedure, examine whether or not
the temperature of the detector terminal block is out of the operating temperature range.
The operating temperature range varies with the type of detector. If the detector
terminal block is out of its operating temperature range, take the measure to lower the
temperature, such as situating it so that it is not subjected to radiant heat.