1170
Other Instructions Section 3-31
Description WDT(094) extends the maximum cycle time for the cycle in which this instruc-
tion is executed. The watchdog timer setting in the PLC Setup is extended by
an interval of T
× 10 ms (0 to 39,990 ms).
The following screen capture shows the PLC Setup setting from the CX-Pro-
grammer.
The following table shows the watchdog timer settings in the PLC Setup. The
default value for the maximum cycle time is 1,000 ms, although it can be set
anywhere from 1 to 40,000 ms in 10-ms units.
Flags
The following table shows relevant flags and words in the Auxiliary Area.
Precautions WDT(094) can be used more than once in a cycle. When WDT(094) is exe-
cuted more than once the cycle time extensions are added together, although
DM Area ---
EM Area without bank ---
EM Area with bank ---
Indirect DM/EM
addresses in binary
---
Indirect DM/EM
addresses in BCD
---
Constants 0000 to 0F9F (binary)
Data Registers ---
Index Registers ---
Indirect addressing
using Index Registers
---
Area T
Name Function Settings
Watch cycle
time
A Cycle Time Too Long error (fatal
error) will be registered if the cycle time
exceeds the maximum setting.
0: Default setting (1,000 ms)
1: User time setting
Sets the maximum cycle time.
(This setting is valid only when the first
setting has been set to 1.)
0001 to 0FA0
(1 to 40,000 ms, 10-ms units)
Name Label Operation
Error Flag ER ON if the watchdog timer setting exceeds 40 seconds.
OFF in all other cases.
Name Address Operation
Cycle Time Too Long
Flag
A40108 ON when the present cycle time exceeds the
maximum cycle time (watch cycle time) set in the
PLC Setup. This is a fatal error which causes pro-
gram execution to stop.
Maximum Cycle
Time
A262 and
A263
These words contain the maximum cycle time in
32-bit binary. This value is updated every cycle.
Present Cycle Time A264 and
A265
These words contain the present cycle time in 32-
bit binary. This value is updated every cycle.
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