Mitsubishi Electric MELSEC iQ-RX40NC6B, Application User'S Manual

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10 FUNCTIONS
10.5 Output Diagnostic Function
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10
Output read-back function
This function reads back the output results for diagnosis to see if the external output signals (Y00 to Y0F) are turned ON or
OFF correctly. By performing diagnostics to see if the output terminal state and the safety device output data match, the
function detects an error in the module's output operation. Note that this function can be used without setting parameters.
The minimum load current (at output ON) of when the output read-back function is used is 3mA/point. If the load current is
below this, the output read-back function may not operate normally.
Operation when an error is detected
When an error is detected during output read-back diagnostics, an output read-back error (error code: 2002H) will occur and
all outputs will be turned OFF.
For the output point where an output read-back error was detected, check it with Output read-back error detection state
(Un\G1536) because a bit of the corresponding output point in this buffer memory area turns on.
The maximum output voltage in output OFF state is 1V. Note that if the voltage exceeds 1V due to a short-
circuit or hardware failure, the connected device may still be in ON state even though the module output is off
because no error is detected when the voltage is lower than 5V.
Y0
OFF→ON
OFF→ON
ON←OFF
ON←OFF
COM
0V
Y0
COM
0V
RY40PT5B(Main)
RY40PT5B(Sub)
24VDC
24VDC
Electromagnetic
contactor
Electromagnetic
contactor
Output
circuit
Output
circuit
Read-back
circuit
Read-back
circuit