Panelview Tag Update Time

Hi,

Looking for some advice regarding the tag update setting in Panelview Plus 7 terminals. We’re starting to install these as upgrades from old DH485 PV550s.

We have several sites. But typically we might have a network with between 2 and 20 SLC 5/05 PLCs, each with a Panelview Plus 7 at each PLC. All the PLCs and HMIs are communicating via managed switch’s, and each HMI only has a shortcut to its own PLC. We also have iFix SCADA on the network. The PLCs all message each other, but they do so on a token basis within each PLC, so only one MSG instruction is executing in each PLC at a time.

The SCADA is set to poll the PLCs for tag updates every 5 seconds, with analogues polling every 1 second.

I think the panelviews poll at 0.25 second intervals.

My question really is, what is the effect of the 0.25 second update time? Will it start flooding the network with traffic? Or is it likely to cause no problems? Do they only update while the page is the current display? Or are the pages updating all the time in the background?

It’s making me think, why there are so many update time options. The SCADAS are apparently set to poll at 5 seconds so they don’t overload the network, but this might be an historical thing from the DH+ days.

On one site - since these panelviews have gone in, the comms times seems to have been causing a few issues - sometimes activating the watchdog timer alarms. But then someone’s been messing about with the SCADA as well - so that could be the issue

Any thoughts on update times on the Panelviews welcome....

Thanks

Andy

I could be wrong, but my thought was

Each page have its update rate set individually, you only need a faster update rate for the page, if it have a display of bit animation to see it flow smoothly.

If the page is having just push buttons and its status displays, an update rate of 0.5 should be decent.

Also I think being a 32 bit system, data transfers are more efficient it the tags are elements of a word rather than bool itself, - a word takes up 4 bytes, so does a single bool in terms of band width. So planning your tag datatype will important as well.

I just found this thread. This is good info.

I have a very small project (5 screens - 4" Panelview) and the values were updating on each screen about once every 3s. The Maximum update rate on each screen was already set to 1s, so I thought "this can't possibly help" seeing as it was updating much slower that once per second, but I tried it anyway and set it to 0.1s on all screens and now it updates much faster (well under 1s)