SLC 5/04 via ControlLogix Bridge Communication Performance Tips?

[witman]

Are there any tips/tricks to get the best communications performance with an SLC 5/04 connected to Ignition via DH±->DHRIO–>ENBT/A? There are also a couple very old RSView HMIs on the DH+ network. There used to be more on it, but we’ve moved everything else off DH+.

We are gradually migrating from RSView to Ignition on this system and are now reading a lot of tags in Ignition.Presently, these are setup in a direct scan class at one second. Lately we’re noticing a few performance issues with the SLC 5/04 (does not affect other PLCs connected to Ignition):
1 - Some tags can take quite a while to show good quality when opening a new window
2 - Communication with SLC 5/04 via RSLogix 500 is slow (obvious when uploading values before save)
3 - RSLogix 500 has difficulty connecting to / staying connected to the SLC

In Ignition 7.9.8, the status page for this device is not very enlightening with status: “Hello world”

Any suggestions/guidelines before playing with scan class(es)?

[pturmel]

You're kind of toast. By default, DH+ is only 57kbits/second. If all of your hardware is compatible, you can select 230k, but it is still a tiny fraction of the bandwidth available to the slowest ethernet processor. RSLogix is a bandwidth hog -- any programming activity will crush your comms.
A short-term fix for some would be to swap the 5/04 for a 5/05, using the DHRIO bridge in the Logix chassis to maintain messaging access from the DH+ devices to the new Ethernet devices. When you do that, do check your comm throttles in your status file:

Typical Performance between Ignition and AB SLC 5/05

Check “Comms Servicing Selection” and “MSG Servicing Selection” for channel 1 (S:2/15 & S:33/7). If either is set, it will crush your throughput, as only one request will be processed per scan (Comms) or per certain control flow instructions (MSG).

[witman]

Thanks Phil. I suspected we would hit this wall eventually.