Output Circuit Troubles And Corrective Actions - Mitsubishi Electric NZ2GFSS2 32D S1 User Manual

Output circuit troubles and corrective actions

The load in the off state momentarily turns on at power off (transistor output).
■Cause
When an inductive load is connected, the load [2] in the off state may turn on due to a sneak current from the back EMF at the
shutoff [1].
Back electromotive
Source output
force
Y0
ON
[2]
Y1
OFF
COM-
IO24V
IO24G
■Action
Take either of the following two actions:
• To suppress the back EMF, connect a diode in parallel with the load under the back EMF influence [3].
Back electromotive
-
+
force
Load
• Configure another current path by connecting a diode across positive and negative of the external power supply.
Back electromotive
Source output
force
Y0
ON
[2]
Y1
OFF
COM-
D1
IO24V
IO24G
D1 indicates the following.
*1
Reverse voltage VR (VRM)
*2
Forward current IF (IFM)
*1 Approximately 10 times as high as the rated load voltage in the performance specifications
Example: 24VDC  Approximately 200VDC
*2 Twice as high as the maximum load current (common) in the performance specifications or more
Example: 2A/1 common  4A or higher
[3]
Load
Load
[1] Shut off
[3]
Load
Load
[1] Shut off
10 TROUBLESHOOTING
10.5 Fault Examples with the Safety Remote I/O Module
10
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