I work in industrial automation, and the amount of polling and high-latency touchscreen issues I encounter is embarrassing.
The default latency of a Rockwell Panelview Plus screen with their FactoryTalk software (the dominant HMI system in North America for custom automation) is 1000 ms. Fixing that solves 80% of the complaints I encounter.
(Unfortunately, it's a dropdown selection list with a limited set of values of 0.05, 0.1, 0.25, 0.5, 1, 2, 5, 10, 60, and a whopping 120 seconds).
> Maximum Tag Update Rate: Specify the maximum rate at which data servers will send data to the tags used in the display, including tags used in expressions and embedded variables. The default update rate is 1.0 second`.[sic] If the update rate is changed, the new rate will not take effect until the display is closed and re-opened.
And it's worse than that - often, response time is on the order of 3 seconds, as described here:
> Well, if you press the button just after the update occurs, you’ll have nearly a whole second go by until it’s read. And once it’s read and sent to the PLC, you’ll then have close to another second until the screen updates again to indicate its on.
I set most of my displays to 0.25 seconds or 0.1 seconds if I can, 50ms is not achievable because Rockwell's Ethernet/IP fieldbus protocol is terribly inefficient and the update rate is a polled refresh of every tag on the screen, you can't have fast buttons and slow production history string arrays.
The default latency of a Rockwell Panelview Plus screen with their FactoryTalk software (the dominant HMI system in North America for custom automation) is 1000 ms. Fixing that solves 80% of the complaints I encounter.
https://i.imgur.com/gEBAA28.png
(Unfortunately, it's a dropdown selection list with a limited set of values of 0.05, 0.1, 0.25, 0.5, 1, 2, 5, 10, 60, and a whopping 120 seconds).
> Maximum Tag Update Rate: Specify the maximum rate at which data servers will send data to the tags used in the display, including tags used in expressions and embedded variables. The default update rate is 1.0 second`.[sic] If the update rate is changed, the new rate will not take effect until the display is closed and re-opened.
And it's worse than that - often, response time is on the order of 3 seconds, as described here:
https://theautomationblog.com/when-factorytalk-view-displays...
> Well, if you press the button just after the update occurs, you’ll have nearly a whole second go by until it’s read. And once it’s read and sent to the PLC, you’ll then have close to another second until the screen updates again to indicate its on.
I set most of my displays to 0.25 seconds or 0.1 seconds if I can, 50ms is not achievable because Rockwell's Ethernet/IP fieldbus protocol is terribly inefficient and the update rate is a polled refresh of every tag on the screen, you can't have fast buttons and slow production history string arrays.