PLC5 watchdog timer

[wilsonzhu]

Hi all, I tried to test the watchdog timer in PLC5-20/E. When I set watchdog timer to 0, CPU still running. Does watchdog time has the low limit? Because I did somthing in SLC500, the CPU will be fault at once. What is the probleum? Thanks a lot !

 

[rdrast]

Just make an infinite loop.

 

[wilsonzhu]

Actually there is a program running in PLC5, its scan time is about 6 ms.

 

[TConnolly]

According to the PLC5 manual, even though Logix5 allows you to enter single digit watchdog times, the minimum watchdog time is 10 milliseconds.

Use an infinite loop.

Q2:1 Q2:1

----[lbl]----------<JMP>--

Edit: if a fault routine is defined it could be running and clearing the fault, then resuming the program.

 

[wilsonzhu]

Thanks a lot!