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TROUBLESHOOTING11.
Table 11.3 Faults with the output circuit and the corrective actions (Continued)
Situation Cause Countermeasure
Example
3
The load is not
turned OFF.
(Triac output)
• The load current is lower than the minimum load current.
• When the load current is lower than the minimum load
current of the output module, the triac does not operate since
the load current flows into a phototriac as shown below.
When an inductive load is connected, the load may not be
turned OFF since surge at the time of OFF is applied to the
phototriac.
• Connect a resistor to both ends of a
load so that the load current is higher
than the minimum load current.
Example
4
When load is
CR type timer,
the time limit
fluctuates.
(Triac output)
• Start the relay first, then start the CR-
type timer at the contact.
In some timers, internal circuit may be
half wave rectification type, so the caution
as to the example 1 is necessary here.
Triac
Surge suppressor
Phototriac
Control
circuit
Load
A1SY22
Output module
Resistor
Load
Leakage current
A1SY22
Output module
CR
timer
Resister
CR
timer
Calculate the
constant of the
resistance based
on the load.
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