Operating Restrictions; Programming Example - Omron CJ2 CPU UNIT User Manual

Appendices
When load L is connected, the ERR indicator may light and the Alarm Output Bit may turn ON for
approximately 100 ms. The programming example given later in this section can be used so that an
error is not detected in this case.

Operating Restrictions

Although the CJ1W-OD202 is provided with short-circuit protection, these are for protecting internal
circuits against momentary short-circuiting in the load. As shown in Figure 2, the short-circuit protec-
tion is automatically released when the Tj equals to Tr. Therefore, unless the cause of short-circuit is
removed, ON/OFF operations will be repeated in the output. Leaving short-circuits for any length of
time will cause internal temperature rise, deterioration of elements, discoloration of the case or
PCBs, etc. Therefore, observe the following restrictions.
Restrictions
If a short-circuit occurs in an external load, immediately turn OFF the corresponding output and
remove the cause. The CJ1W-OD202 turns ON an alarm output bit that corresponds to the external
load output number. There is an alarm output bit for every common.
When an alarm output bit turns ON, use a self-holding bit for the alarm in the user program and turn
OFF the corresponding output.
The alarm output bit is allocated in the Basic I/O Unit Information Area (A050 to A069) for every Unit
mounting slot.
The following table shows the correspondence between output bits and bits in the Basic I/O Unit
Information Area.
CJ1W-OD202
For example, when the CJ1W-OD202 is mounted in slot 0 on Rack 0, A50.00 will turn ON if the out-
put 0 is short-circuited. When the CJ1W-OD202 is mounted in slot 1 of Rack 0, A50.11 will turn ON
if the output 7 is short-circuited.

Programming Example

In this example, CJ1W-OD202 is mounted in slot 0 of the Rack 0.
This example shows how to turn OFF output bits CIO 0.00 immediately if the alarm output bit A50.00
turns ON and how to keep the output bits OFF until the cause is removed and the bit is reset using
work bit W0.01.
Change to CIO 0.00, CIO 1.00, 0 (under TIM and at bottom right of diagram), A50.00, and W0.01.
To prevent the alarm output bit from turning ON momentarily when the load turns ON, the alarm out-
put is not turned ON for 200 ms after the input (CIO 1.00) turns ON.
A50.00
TIM0
W0.00
1.00
A-150
Output bit
Mounted in even slot
Mounted in odd slot
1.00
TIM
0000
#0002
W0.01
W0.00
W0.00
0.00
0 to 1 2 to 3
0 1
8 9
4 to 5 6 to 7
2 3
10 11
CJ2 CPU Unit Hardware User's Manual