Troubleshooting For Output Circuit - Mitsubishi Electric NZ2MF2S1-32D User Manual

Troubleshooting for output circuit

A load momentarily turns on when the external power supply is powered on
■Cause
An incorrect output occurs due to the stray capacitance (C) between collector and emitter of a photocoupler.
There is no problem with the normal load. When a high sensitivity load (such as solid state relay) is used, however, this
incorrect output may occur.
Output module
Photocoupler
C
Tr1
Ic
Constant-
voltage circuit
When the external power supply is powered on rapidly, the current (Ic) flows due to the stray capacitance (C) between
collector and emitter of a photocoupler.
The current (Ic) flows to the gate of the transistor (Tr1) of the next stage and the output Y0 turns on for approximately 100s.
SW: External power supply
(24VDC) at ON
Output Y0
Y0
Load
CTL+
SW
COM-
24VDC
10ms or less
Approx.100µs
11 TROUBLESHOOTING
11.4 Examples of Troubles with the I/O Module
11
107