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14. Troubleshooting
If any malfunctions occur, refer to the following items after checking that power is being supplied to the
controller.
14.1 Indication
Problem
Presumed Cause and Solution
[
] is flashing on the
PV/SV display.
• Thermocouple, RTD or DC voltage (0 to 1 V DC) is burnt out.
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
approximate 0
(32
) is indicated, the instrument is likely to
be operating normally, however, the sensor may be burnt out.
[DC voltage (0 to 1 V 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 1 V DC) are securely mounted to the instrument input terminals.
Connect the sensor terminals to the instrument input terminals securely.
[
] is flashing on the
PV/SV display.
• Check whether input signal source for DC voltage (1 to 5 V DC) or
DC current (4 to 20 mA DC) is disconnected.
How to check whether the input signal wire is disconnected
[DC voltage (1 to 5 V DC)]
If the input to the input terminals of the instrument is 1 V 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 20 mA DC)]
If the input to the input terminals of the instrument is 4 mA 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 5 V DC) or DC
current (4 to 20 mA 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/SV display keeps
indicating the value which was
set during Scaling low limit
setting.
• Check whether the input signal source for DC voltage (0 to 5 V DC,
0 to 10 V DC) and DC current (0 to 20 mA DC) is disconnected.
How to check whether the input signal wire is disconnected
[DC voltage (0 to 5 V DC, 0 to 10 V DC)]
If the input to the input terminals of the instrument is 1 V 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.
[DC current (0 to 20 mA DC)]
If the input to the input terminals of the instrument is 4 mA 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 lead wire terminals for DC voltage (0 to 5 V
DC, 0 to 10 V DC) or DC current (0 to 20 mA DC) are securely
mounted to the instrument input terminals.
The indication of PV/SV display
is irregular or unstable.
• Check whether sensor input or temperature unit (
or
) is correct.
Select the sensor input and temperature unit (
or
) properly.
• Sensor correcting value is unsuitable. Set it to a suitable value.
• Check whether the specification of the sensor is correct.
• AC leaks into the sensor circuit. Use an ungrounded type sensor.
• There may be equipment that interferes with or makes noise near
the controller.
Keep equipment that interferes with or makes noise away from the
controller.
The PV does not change.
• SV may be selected during Display selection in the Special
function group. Select indications other than SV.
