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13. Troubleshooting
If any malfunctions occur, refer to the following items after checking that power is being supplied to
the controller.
13.1
Indication
Problem
Possible Cause and Solution
[
], nothing or PV 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 terminals of the instrument are 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 a value around 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 terminals of the instrument are 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 terminal.
Connect the sensor terminals to the instrument input terminals
securely.
[
] is flashing on the PV
display.
• Check whether input signal wire for DC voltage (1 to 5V DC) or
Direct 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.
[Direct 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 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.
The PV display keeps
indicating the value which
was set in [Scaling low limit].
• Check whether the input signal wire for DC voltage (0 to 5V DC,
0 to 10V DC) and Direct 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
a value (converted value from scaling high, low limit setting)
corresponding to 1 V DC is indicated, the instrument is likely to be
operating normally, however, the signal wire may be disconnected.
[Direct current (0 to 20mA DC)]
If the input to the input terminals of the instrument is 4mA DC and
if a value (converted value from scaling high, low limit setting)
corresponding to 4 mA DC is indicated, the instrument is likely to be
operating normally, however, the signal wire may be disconnected.
• Check whether the input terminals for DC voltage (0 to 5V DC,
0 to 10V DC) or Direct current (0 to 20mA DC) are securely
connected to the instrument input terminals.