The load in the off state momentarily turns on at power off (transistor output).
Cause
When an inductive load is connected, the load in the off state (2) may turn on due to a sneak current from the back EMF at the shutoff (1).
• Sink output
ON
OFF
• Source output
ON
OFF
9 TROUBLESHOOTING
126
9.3 Output Circuit Troubles and Corrective Actions
Back EMF
(3)
Y0
Load
(2)
Load
Y1
12/24VDC
(1)
Shut off
COM
Back EMF
(3)
Y0
Load
(2)
Load
Y1
(1)
Shut off
COM
0V