Mitsubishi A2USCPU(S1), User Manual

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TROUBLESHOOTING 11.
11.4.2 Faults in the output circuit
Faults concerning output circuits and the corrective actions are explained.
Table 11.3 Faults with the output circuit and the corrective actions
Situation Cause Countermeasure
Example
1
An excessive voltage is
applied to the load when
output is off.
• When the load is subjected to half wave
rectification inside
(Solenoids have these types.)
• When the polarity of the power supply is [1], C
is charged, and when the polarity is [2], the
voltage charged in C + voltage of the power
supply are applied to the both ends of D1.
The maximum value of the voltage is about
2.2E.
• Connect a resistor with several tens to
several hundreds of k to the both ends of
the load.
With this kind of usage, there is no problem
with the output element, but the diode built-
in to the load may deteriorate and burn-out.
Example
2
Load does not turn OFF.
(Triac output)
• Leak current caused by built-in noise
supressor
• Connect a resistor to the both ends of the
load.
When the wiring distance from the output
card to the load is long, be aware of the risk
of a leak current due to line capacity.
Output module
A1SY22
D1
[1]
[2]
Load
Resister
Load
Load
Leakage current
A1SY22
Output module
Resister
Load