Typical performance of LogixDriver throughput

Could someone give me an indication of whether the throughput of my project’s LogixDriver is typical, or whether I could get faster tag updates through configuration changes.

PLC: CompactLogix L33ER firmware version 20.19
Ignition OPC UA device driver: Allen-Bradley Logix Driver (Optimized for devices with firmware v21+ but supports earlier firmware versions with significantly reduced performance)

Gateway PC: Dell Optiplex 7090 Small Form Factor, 16GB RAM, SSD, 11th Gen Core-i7-11700T, Windows 11

Project: Relatively simple, about 20 views, not a lot going on other than simple tag displays and some historical logging of tag data. No significant supplementary load from project specific gateway scripts, database interactions etc.

Tag performance: ~2000 tags, actual sampling interval 3950ms, device overload 294% referenced to a 1000ms sampling rate.

Gateway PC Loading:

I note that there is a legacy driver for CompactLogix v20.18 and below. I did redivert my project to an instance of this driver but I got no throughput at all. I discovered when I tried to add a new tag to the project by browsing the PLC device, only top level folders were extracted from the PLC with no member tags within. This is probably because the driver is for v20.18 and below.

It seems on v20.19 my PLC is in a vacuum between the legacy driver optimised for v20.18 down and the current CompactLogix driver which is for v21 and above (citing compatibility but with poor performance for lesser firmware versions).

A firmware shift aside, is the device driver performance I am seeing on hardware of this caliber typical or can I expect better (sub 1s tag updates for 2000 tags)?


It’s expected to be bad if you’re stuck in the firmware 20.15 - 20.19 range. You might squeeze a little more out if you can use a periodic task or continuous task with a significantly increased overhead timeslice and bumping the concurrent requests setting on the driver up a little bit.

Best case would be downgrade to 20.11 and use the legacy driver. Second best case would be 21+ and use the new driver.

Cheers, I’ll give best case a go! :slight_smile: