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14. Troubleshooting
If any malfunctions occur, refer to the following items after checking the power supply to the controller.
14.1 Indication
Problem
Presumed cause and solution
[
] is indicated on the PV
display.
• Control output OFF function is working.
Press the
key for approx. 1 second to release the function.
[
] is flashing on the PV
display.
• Burnout of Thermocouple, RTD or disconnection of DC voltage (0 to
1V DC)
Change each sensor.
How to check whether the sensor is burnt out
[Thermocouple]
If the input terminal of the instrument is shorted, and if a value
around room temperature is indicated, the instrument is likely to
be operating normally, however, the sensor may be burnt out.
[RTD]
If approx. 100
of resistance is connected to the input terminals
between A-B of the instrument and between B-B is shorted, and
if approximate 0
(32 ) is indicated, the instrument is likely to be
operating normally, however, the sensor may be burnt out.
[DC voltage (0 to 1V DC)]
If the input terminal of the instrument is shorted, and if a scaling
low limit value is indicated, the instrument is likely to be operating
normally, however, the signal wire may be disconnected.
• Check whether the input terminals of thermocouple, RTD or DC voltage
(0 to 1V DC) are securely mounted to the instrument input terminals.
Connect the sensor terminals to the instrument input terminals securely.
[
] is flashing on the PV
display.
• Check whether input signal source for DC voltage (1 to 5V DC) or
DC current (4 to 20mA DC) is disconnected.
How to check whether the input signal wire is disconnected
[DC voltage (1 to 5V DC)]
If the input to the input terminals of the instrument is 1V DC and
if a scaling low limit value is indicated, the instrument is likely to be
operating normally, however, the signal wire may be disconnected.
[DC current (4 to 20mA DC)]
If the input to the input terminals of the instrument is 4mA DC and
if a scaling low limit value is indicated, the instrument is likely to be
operating normally, however, the signal wire may be disconnected.
•
Check whether input signal wire for DC voltage (1 to 5V DC) or DC current
(4 to 20mA DC) is securely connected to the instrument input terminals.
• Check if polarity of thermocouple or compensating lead wire is correct.
•
Check whether codes (A, B, B) of RTD agree with the instrument terminals.
PV display keeps indicating the
value which was set during
Scaling low limit setting.
• Check whether the input signal source for DC voltage (0 to 5V DC,
0 to 10V DC) and DC current (0 to 20mA DC) is disconnected.
How to check whether the input signal wire is disconnected
[DC voltage (0 to 5V DC, 0 to 10V DC)]
If the input to the input terminals of the instrument is 1V DC and if
the value corresponding to 1V DC is indicated, the instrument is
likely to be operating normally, however, the signal wire may be
disconnected.
[DC current (0 to 20mA DC)]
If the input to the input terminals of the instrument is 1mA DC and
if the value corresponding to 1mA DC is indicated, the instrument
is likely to be operating normally, however, the signal wire may be
disconnected.
