Mitsubishi A1SJH User Manual

11. TROUBLESHOOTING
11 - 18
MELSEC-
A
11.4.2 Output circuit failures and corrective action
Table 11.3 Output circuit failures and corrective action
Condition Cause Corrective action
Example
1
When the
output is OFF,
excessive
voltage is
applied to the
load.
•
Load is half-wave rectified inside (in some cases,
this is true of a solenoid).
A1SY22
Output module
Load
D1
(1)
(2)
When the polarity of the power supply is as 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.
•
Connect a resistor of 10 to 99 k
Ω
.
across the load.
If a resistor 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.
Resistor
Load
Example
2
The load does
not turn OFF
(triac output)
•
Leakage current due to built-in noise suppression
A1SY22
Output module
Load
Leakage current
•
Connect C and R across the load.
When the wiring distance from the output
card to the load is long, there may be a
leakage current due to the line capacity.
Resistor
Load
Example
3
When the load
is a CR type
timer, time
constant
fluctuates
(triac output).
A1SY22
Output module
CR timer
Leakage current
•
Drive the relay using a contact and drive the
CR type timer using the same contact.
Some timers have half-wave rectified internal
circuits. Therefore, take the precautions
indicated in the Example1.
Resistor
CR timer
Calculate the CR constant
depending on the load.

Mitsubishi A1SJH Specifications

General

Brand	Mitsubishi
Model	A1SJH
Category	Controller
Language	English