Allen Bradly Control Logix - Progress Bar updating issue

Hello all,

Im trying to understand/get to the bottom of an issue im having with a progress bar. Im using Ignition 8.1, Vision and i have a progress bar element added to a page. The progress bar is linked to a Tag in a control logix PLC using the allen bradly logix driver. The tag just recives an increasing number from a 1 second pulse.

1 sec pulse > Add Block > TAG:Count Total

When watching the pulse in the designer it seems to be skipping counts. The counter in the plc counts up to 12 seconds then resets but the progress bar in ignition will see it at 6, 11, 5 even sometimes skip. It seems to be related to scan time.

I tried to add a tag group called “high speed scan” were i set the scan time to 10ms (compared to 1s default) and still had the issue.

Its lead me into the device configuration in the OPC UA configuration. I notice the setting “Max Concurrent Requests”. Its set to 2 by default. Would increasing this number solve my issue? also in the advanced options their is “Identity Request Frequency” (5 seconds by default).

is my sampling of information being limited by these 2 numbers? If im on the right track i understand increasing these effects a few things. Whats a safe number & how can i determine what this safe number is?

If im no were on track can someone point me in the correct direction?

Thanks

Take a screenshot of your device’s diagnostic page. It sounds like you’ve overloaded it. This is often caused by a newbie mistake: dragging everything from the OPC browser over to Ignition’s tag browser. (You should only have tags in Ignition for the OPC items you need.)

FWIW, a 10ms scan time is overly optimistic for any polling PLC driver in Ignition.

This topic should help:

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Thanks mate,

That’s exactly what I did. Ill investigate tomorrow and clean up what tags are moved over & see if that solves the issue. 10ms was just some arbitrary number that was low for testing.

Ben

The client poll rate may also need to be lowered if you want to see fast changes like this.

His initial problem was not seeing changes for several seconds that should have been one second (default rate).

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Oh yeah, that sounds like overload then.

I presume the “That’s exactly what I did” refers to the newbie mistake I speculated on. (:

your speculation is correct. Not at work to try and correct it though. Tomorrows job.

When you clean out the tag list, think about organizing your tags by folders for plant & machine subsystems. They don’t have to follow the PLC’s organization at all. Organizing by physical setup helps make re-usable templates and windows.

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