YOKOGAWA av550g, Руководство пользователя

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< 12. Troubleshooting >
12-10
IM 11M12D01-01E
4) Alarm 4: Calibration time over (EMF stabilization time-up) alarm
This alarm is generated if the sensor (cell) voltage has not stabilized even after the calibration time is
up for the reason that the calibration gas (zero gas or span gas) has not filled the sensor assembly of
the detector. The following are suspected as the cause:
(1) The flow of the calibration gas is less than normal (a specified flow of 600 ± 60 ml/min).
(2) The length or thickness of the calibration gas tubing has been changed (lengthened or
thickened).
(3) The measuring gas flows toward the tip of the probe.
(4) The sensor (cell) response has deteriorated.
<Locating cause of failure, and countermeasures>
(1) Carry out calibration by passing the calibration gas at the specified flow (600 ± 60 ml/min) after
checking that there is no leakage in the tubing.
(2) If calibration is carried out normally, perform a steady operation without changing the conditions.
If the alarm occurs again, check whether or not the reason is applicable to the following and then
replace the sensor assembly.
• A lot of dust and the like may be sticking to the tip of the detector probe. If dust is found, clean
the probe (see Subsection 11.3.1). In addition, if an alarm occurs in calibration even after the
sensor assembly is replaced, the influence of sample gas flow may be suspected. Do not let the
sample gas flow toward the tip of the detector probe, for example, by changing the mounting
position of the detector.
5) Alarm 5: 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°C or exceeds 155°C. Check the following:
Display “C.J.Temperature” in the [Detailed data] display. If “C.J.Temperature” is indicated as 200°C or
-50°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.
<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.
The case where the Model ZR22 Detector is used:
(1) Stop the power to the converter.
(2) Remove the wiring from terminals 5 and 6 of the detector and measure the resistance between
these terminals. If the resistance value is out of the range of 1 to 1.6 kΩ, the cold junction
temperature sensor is considered to be faulty. Replace that temperature sensor with a new one.