Mitsubishi Electric NZ2GN2S1-16D User Manual page 211

When output is turned on, load connected to other outputs is turned on simultaneously
■Cause
When a non-wiring state occurs due to, for example, a shutoff or disconnection between 0V of the external power supply and
the common of a load, a current flows across the load that is off through an unexpected circuit of the output element that is off.
Output module
Source output
ON
Output control
circuit
OFF
Output control
circuit
■Action
Connect external power supply and the load correctly.
To prevent the state described above, install diodes in each output terminal as shown below.
Source output
Y0
Y1
COM+
24VDC
CTL-
Load
Y0
Load
Y1
COM+
24VDC
CTL-
Load
Load
Shutoff or disconnection
11.5 Examples of Troubles with the I/O Module
11 TROUBLESHOOTING
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