Disabling Function Group effect on performance

Brendon 7 months ago in IQANdesign updated 6 months ago 3

Does Enabling/Disabling a Function Group have any effect on performance?
Does the code in the function group still run when it's disabled?

If I'm understanding your question correctly you want to have a function group (or multiple) that you turn on and off to change options in the machine operation?  If so, I have been doing that for many years with no issues.  I highlighted the MVEC OC below and in this case when the assembly tech selects the open cab mode in the adjust menu (with a PIN password to keep the operator from messing the modes up!) the state parameter switches the Open Cab IDC True (which enables the MVEC OC FG), and the Closed Cab IDC False (Disables the MVEC1 and MVEC2) and this changes the operation mode of the whole system.  There are other ways this can be done but I know this works.

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When a function group is disabled, the channels are still loaded in memory so memory utilization does not change. 

Channels in disabled function groups are not calculated, so you do get a slightly lower cycle utilization. 

If you have large function groups that can be disabled/enabled, t is good to check that your cycle utilization has margins to the case when all are enabled. 

Hey guys,

Thanks for you replies.  Just a bit more backstory.... 

This stemmed from having screen lag issue I was trying to resolve.  I had a significant amount of alerts across multiple function groups, they were causing lag navigating between MD4 display pages. I was considering using in DIN to Enable/Disable each function group, where they would only activate if an alert were active.

I wasn't experiencing the same issue during Simulate, at least not nearly to the same degree the MD4 was experiencing. 

I attempted to recreate the issue in Simulate by placing a math channel with an extraordinarily long series of if/then statements in a function group, then enable it.  I was expecting the system to run fine, until I enabled the function group, at which point the Simulation would stall out, or show some performance decline, but that didn't seem to happen.   It wasn't conclusive whether Enable/Disabling had any effect.  So thank you Gustav for confirming , that in fact channels are not calculated.

In the end, I ended up clearing the lag issue by splitting up the alerts onto specific display pages, each dedicated to a certain function group, rather than display all on a single page.  I have also implement the Enable/Disable function group feature, but it doesn't seem to play a significant role in performance when navigating between screens.