Mitsubishi Electric CC-Link IE-NZ2GNSS2-16DTE, User Manual

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8 FUNCTIONS
8.5 Input Diagnostic
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8
Input dark test function
Outputs test pulses to turn off the external input signals (X0 to X7) that are on and diagnoses contacts including external
devices for failure. Failures including circuit fixing and short-circuit faults can be detected.
The input dark test detects a short-circuit fault that occurs between Xn (n: even number) and Xn+1. The Xn is an input
terminal to be connected to T0, and the Xn+1 is an input terminal to be connected to T1. Note that a short-circuit fault between
Xn and Xn or between Xn+1 and Xn+1 cannot be detected. Thus, do not use the input dark test for a system where a short-
circuit fault may occur between Xn and Xn or between Xn+1 and Xn+1.
The OFF time of test pulses and the number of pulse outputs used in one diagnostic can be set depending on the usage
environment.
To use the input dark test function, use the test pulse output terminals (T0, T1) and connect input devices.
Use the input terminals and test pulse output terminals (T0, T1) of the safety remote I/O module in the following combinations.
An incorrect combination results in an error.
When the input dark test is not executed, input devices can be connected with a combination of input
terminals and COM+ terminals.
Operation at error detection
When an error is detected in a diagnostic of the input dark test, the input dark test error (error code: 0204H) state is applied.
For details on the error state, refer to the following.

Page 118 Error codes related to the safety remote I/O module
When an error occurs for all the input points due to the input dark test error or double input discrepancy
detection error and the input function cannot be performed anymore, an I/O data error (error code: 0108H)
results. However, when a double input discrepancy detection error (error code: 0203H) occurs while "1: Used"
is set for the parameter "Double input discrepancy auto recovery setting", the input function may be
recovered. Thus, an I/O data error (error code: 0108H) does not occur even if the error occurs for all the input
points.
(1) Test pulse
(2) Safety remote I/O module
Test pulse output terminal Input terminal
T0 X0, X2, X4, X6
T1 X1, X3, X5, X7
(1)
(1)
(2)
NC
NC
T0 T1 X0 X1