Retentive Timer On issue

Hey all,

I wrote some ladder logix using RSLogix 5000 v15. When I make changes to the logic, I download it to the PLC. I use some Retentive timer on's to keep track of how long pumps have been running.

The Problem: When I download the modified programs to the PLC the Retentive Timer resets to some value, not zero, instead of staying the same. I saved the project once when I was online and in run mode and it asked me if i want to save the tag values as well and I did. Now everytime I make a change, the value resets to the value it was saved as.

Does anybody know how to disable that feature and let the Retentive Timers not reset to the saved value?? Or am I screwed??

Thanks,
-Ken

The only for sure way of not changing a timer's accumulated value (or the entire data table for that matter) is to make the program changes online. Otherwise, whatever is in your offline data table will be transferred to the processor on a download.

I think you are SOL in version 15. What I usually do is make changes offline, and instead of downloading the program make copy and paste in online changes to the ladder so that the data table values are not affected. I believe in version 17 there is a partial download ability but I haven't investigated it very much.

Create a startup routine that zero's the acc values of your retentive timers/counters.

If its in memory it can get changed, intentionally or accidentally. If you absolutely don't want to chance it then use external hour meters.

BTW, if you have the FB language extensions for Logix5000 then consider using the TOT instruction instead for traking motor run hours.
See http://www.plctalk.net/qanda/showpost.php?p=251927&postcount=5 for information on how to configure it to totalize hours and using the TOT flags.

Oakley said:

Create a startup routine that zero's the acc values of your retentive timers/counters.

Click to expand...

I don't think he wants them to start over. He wants them to maintain their current count of time running, even when a new program is dumped in.

My suggestion is do an Upload just before dumping, cut/paste your new logic in offline, and dump the new program back in. That's whay I usually do to insure that I have fresh data.

robertmee said:

I don't think he wants them to start over. He wants them to maintain their current count of time running, even when a new program is dumped in.

My suggestion is do an Upload just before dumping, cut/paste your new logic in offline, and dump the new program back in. That's whay I usually do to insure that I have fresh data.

Click to expand...

Ok then, you could use the Tag Upload/Download tool from RA.