Ignition Version 7.5.8
While changing my program in the PLC I’m losing connection to the PLC tags for several seconds.
Is this a AB specific problem?
Is there a fix?
That’s just life my friend.
When the edit number (when the program) changes the tags can’t be safely read at their previous memory locations any more, so the processor needs to be re-browsed to obtain the new memory locations.
I’m having the same issue. I need to make changes “while” ignition is running. Any little change that I make in my PLC program, makes my ignition tags go RED. If this happens ignition code doesn’t get triggered and data is missed, causing a fault on my system. Any help would be appreciated.
Thanks
[quote=“drinaldi”]I’m having the same issue. I need to make changes “while” ignition is running. Any little change that I make in my PLC program, makes my ignition tags go RED. If this happens ignition code doesn’t get triggered and data is missed, causing a fault on my system. Any help would be appreciated.
Thanks[/quote]
I too will jump onto this thead as something has changed with online edits. I too have witnessed while doing a change online with a Contrologix program all tags will go red after an online edit. Have not seen this before in previous revisions.
This can happen when there are too many requests sent to the device. You are re-browsing the device and it may not be able to handle the number of requests being sent to it. This can be true if you have fast scan classes on the device, and even if you have the number of concurrent requests set too high or too low. This is just the way that the driver responds. With some fine tuning you may be able to eliminate this from happening when making changes to the device.
One of my controlLogix PLC’s is using a redundeny module and I have seen the tags all go red for at least 10 seconds during minor program changes such as FORCES.
The other ControlLogix without the redundency seems to only “go red” when the PLC program is uploaded.
I have around 2000 tags in each PLC and I have around 200 with scan class 500ms and the rest are 1 second. Concurrent requests was changed from 2 to 4 and it appears to have reduced the frequency of the bad quality tags by 50 percent or so but I haven’t done any specific testing.
I am glad to hear that the changes are making an improvement