I am looking for the easiest way to calculate the time difference in a slc 5/03. I would like to capture the time when a fault happens and again when the machine is restarted. After that calculate the difference in the times and place that into a register that will allow me to add to it each time the same fault happens. Thanks for any help

If the time between the fault and the restart will be less than 9 hours just start a TON with an Preset of 32767 and a base and 1.0 seconds when the fault occurs. Then when you see the machine restart move the TONs accumulated value to you register.

This will only work to a little over 9 hours though. 32767/3600 = roughly 9.1 hours.

If you need more time that that we will have to do a little more

Thanks for your reply. I was looking at this option also but, was unsure if a rto would be better because of having to keep track of the time through out the day. I would also rest the timers through an opc connection every 8 hours.