KEPServerEX 6.16 - BACnet - How to see what the poll rate really is?

[Tanquen]

I'm using Ignition to read about 4800 values from some BACnet devices.

The on site enteliWEB app shows values updating every few seconds. But it can take a minute or more before Ignition updates the value to something else. They almost never match as it takes too long to get the updated value from KEPServerEX.

The default poll rate in Ignition is 250ms and in KEPServerEX the BACnet device is set to "Respect Client Specified Scan Rate" by default. I've also tried the "Request Data at Scan Rate" set to 100ms. The tags always seem to show their scan rate at 100ms.

[rajskumar]

Hello,

As concluded during your submitted case investigation, it is a limitation of the BACnet protocol due to its UDP-based transport layer method. It was suggested that separating the devices on multiple channels (our driver help file suggests the same on page 34) and using Aliases features is the way to go.

I am posting this here to help other community members having a similar issue. Thanks.

[Tanquen · Accepted solution]

Yes, unfortunately there is nothing you can really do but give up a bunch of IP addresses.

It’s a frustrating issue. We are getting all the points it just that some updates are taking longer than I’d like and the only real fix for the BACnet protocol is to put fewer devices on more channels that each need an IP address. To test any new configuration there is a lot of re-work changing the Ignition HMI paths to the points and so on. Just to see if it help enough. 

How many do we need, something between one for each (160-ish) and the 4 we have now? We added one and it did not help that much. We need to get them down to maybe 4 devices per IP address/channel. Fun stuff.