Measured Temperature Value Is Abnormal - Mitsubishi Q68TD-G-H01 User Manual

8
TROUBLESHOOTING
8.2.9
Check Item
Check whether the connected thermocouple or
compensation conductor differs from the setting.
Check whether the connected thermocouple or
compensation conductor is connected reversely.
Check the wiring.
Check for noise in the thermocouple input.
Check the cold junction temperature compensation resistor
(RTD) for making cold junction temperature compensation for
wire disconnection or disconnection from the relay terminal
block.
Check whether the cold junction temperature compensation
yes/no setting is correct.
Check whether conversion is made with the other
thermocouple set after setting of the offset/gain value
Check whether wiring between the module and terminal
block is correct.
The Q68TD-G-H01 module was mounted in the limited
position in the system using the power supply module of the
Q63P, Q63RP, Q64P or Q64RP.
Check whether the effect of temperature error due to wiring
resistance of a thermocouple is large.
8
- 6 8.2 Troubleshooting

8.2.9 Measured temperature value is abnormal

Measured temperature value is abnormal
Table 8.10 Measured temperature value is abnormal
POINT
The module may be faulty if the measured temperature values cannot be read
after proper corrective actions have been taken according to the above check
items. Please consult your local Mitsubishi representative.
Set the thermocouple type connected to the switch 1 or 2 in
the intelligent function module switch setting of GX
Developer.
Connect the thermocouple or compensation conductor
correctly.
Refer to Section 4.4.2 (1) Wiring procedure, and wire cables
and compensating lead wires correctly.
Check influence from the ground and adjacent devices, and
take action to prevent noise.
Check that the cold junction temperature compensation
resistor (RTD) is connected to the relay terminal block and
there is continuity, and if not, connect or change the cold
junction temperature compensation resistor (RTD).
Set the switch 4 to the correct position in the intelligent
function module switch setting of GX Developer. (Refer to
Section 4.5.)
Make offset/gain setting again after changing the
thermocouple.
Check that wiring between the module and terminal block is
performed correctly.
Refer to Section 2.1 (2) Restrictions on mountable slot
position in which the module can be installed.
Check the wiring resistance value of the thermocouple and
calculate the temperature error in the system. (Refer to
Section 3.1(2))
If the error is large, it may cause a change of the measured
temperature value. Correct the measured temperature value
by the offset/gain setting. (Refer to Section 4.6.)
Remedy