CPU LED.

[chiali]

Hi all,
The CPU LED of my DL05 PLC turns ON from time to time (Randomly after many cycles of the machine process.);
so I have to power cycle to restart the machine.
Could it be a programming problem?
What should I do to avoid this?
 

[Greg]

If you haven't already done so, you may want to contact Automation Direct techs, or post this question on their forum. However, if the CPU light is turning on it could be caused by one or more of these things:

• Noisy power
• Bad grounding
• Programming that causes the CPU watchdog to timeout.

The CPU watchdog timeout is, by default, 200ms. In other words, if the scan of the PLC was to periodically exceed 200ms, then the CPU light would turn on. You could cause the scan of the PLC to increase in time by having For/Next loops that take too much time, or you could've changed the watchdog timeout value down from 200ms... something like that.