Filter
Top Products
11 - 41 11 - 41
MELSEC-Q
11 TROUBLESHOOTING
11.5.2 Output Circuit Troubleshooting
This section explains trouble examples and troubleshooting methods in the output
circuit.
Output Circuit Troubleshooting
Condition Cause Corrective Action
Example 1
Excessive
voltage is
applied to
load when
output turns
off.
• When load is half-wave rectified inside
(This is typical of some solenoids.)
QY22
[1]
[2]
D1
C
Output module
Load
• When the polarity of the power supply is [1],
the capacitor C is charged. When the polarity
is [2], the voltage charged in C plus the power
supply voltage is applied to across D1. The
maximum value of the voltage is approx. 2.2E.
(This usage does not pose problems to the
output components but may deteriorate the
diode built in the load
,
causin
g
burnout
,
etc.
)
• Connect a resistor of several ten K
to several
hundred K
across the load.
Load
Resistor
Example 2
Load does
not turn off.
(Triac
output)
• Leakage current due to the built-in surge
suppressor
QY22
Output module
Load
Leakage current
• Connect a resistor across the load.
(If the wiring from the output module to the
load is long, be careful since there may be a
leakage current due to the line capacity.)
Load
Resistor