Output Circuit Troubleshooting - Mitsubishi QX10 User Manual

11 I/O MODULE TROUBLESHOOTING

11.2 Output Circuit Troubleshooting

Condition
When the • Load is half-wave rectified inside (in some
output is
off,
excessive
voltage is
applied to
the load.
• When the polarity of the power supply is as
The load • Leakage current due to built-in surge
does not
turn off.
(triac
output)
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This section describes possible problems with output circuits and their corrective
actions.
Table 11.2 Output Circuit Problems and Corrective Actions
Cause
cases, this is true of a solenoid).
QY22
Output module
Load
shown in [1], C is charged. When the polarity is
as shown in [2], the voltage charged in C plus
the line voltage are applied across D1. Max.
voltage is approx. 2.2E.
(If a circuit is used in this way, it does not pose
a problem to the output element. But it may
cause the diode, which is built into the load, to
deteriorate, resulting in a fire, etc.)
suppressor.
QY22
Output module
Leakage current
• Connect a resistor several tens to hundreds of
kΩ across the load.
[1]
D1
[2]
• Connect a resistor across the load.
(When the wiring distance from the output
module to the load is long, there may be a
leakage current due to the line capacity.)
Load
MELSEC-Q
Corrective action
Resistor
Load
Resistor
Load
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