Omron NJ501-1400 User Manual page 380

Appendices
Figure 3 Operation for Disconnected Line with Output Current below the Line Disconnection
Detection Current
ON
OUT
OFF
ON
I
OUT
OFF
ON
ERR
OFF
A: Load not connected or load line broken.
B: Current to load at or below line disconnection detection current.
C: Rise of current to load too slow and error detected before the disconnection detection current was
reached.
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 in the next section can be used so that an
error is not detected in this case.
 Operating Restrictions of CJ1W-OD202
Although the CJ1W-OD202 is provided with load short-circuit protection, these are for protecting
internal circuits against momentary short-circuiting in the load. As shown in Figure 2, the load short-
circuit protection 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 two outputs.
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 Bits are allocated in the Basic I/O Unit Information Area system-defined variable.
Two output bits are assigned for each slot and rack in which a Unit is mounted.
_CJB_IOUnitInfo[rack_number,slot_number,serial_number_in_Unit]
For example, when the CJ1W-OD202 is mounted in slot 0 of rack 0, _CJB_IOUnitInfo[0,0,0]
changes to TRUE if output Ch1Out0 changes to TRUE. When the CJ1W-OD202 is mounted in slot
1 of rack 0, _CJB_IOUnitInfo[0,1,3] changes to TRUE if output Ch1Out7 changed to TRUE.
A-96
I
OL
A B C
NJ-series CPU Unit Hardware User's Manual (W500)