Cold Junction Temperature Compensation Resistor Disconnection Detection Function - Mitsubishi MELSEC-Q Series User Manual

3
SPECIFICATIONS
3.2.4 Cold junction temperature compensation resistor disconnection
detection function
(1) When the connected cold junction temperature compensation resistor is
disconnected, an error (error code 800) occurs. Then the error flag (XF)
turns ON and the "ERR." LED tunrs on to notify the error.
(2) Disconnection of the cold junction temperature compensation can be
detected only when the switch setting 4 of the intelligent function
module is set to "with cold junction compensation".
RTD
Without disconnection
RTD
With disconnection
Without connection
(3) When disconnection of cold junction temperature compensation is
detected, conversion for every conversion-enabled channel stops.
For the measrued temperature value at cold junction temperature
compensation resistor disconnection, the value before disconnection is
held.
(4) Conversion processing does not restart even after the disconnection of
the cold junction temperature compensation register is recoverd.
To restart the conversion processing, turn ON then OFF the error clear
request (YF).

3.2.4 Cold junction temperature compensation resistor disconnection detection function

Table 3.6 Disconnection detection of cold junction temperature compensation
Connection state
Cold junction temperature
with/without setting
+
with
-
GND
without
+ with
-
GND
without
+
with
-
GND
without
3.2 Function List
1
2
3
Error flag
OFF
4
ON
OFF
5
ON
OFF
6
7
8
3
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