Panelview plus Data blocks

Normally when we program control logix with a panelview plus hmi we create a ToHMI[50] Dint and a FromHMI[50] Dint. This allows the HMI to read and write in single data blocks making the update rates faster.
I hate working with bits cause I can never remember which bit I used for each functional. Therefore, I'm always looking at the bit descriptions to determine what I am using each one for.

I got thinking...

If I create a UDT with all the required bool tags, Dint tags, and Real tags needed for the HMI, one UDT for "ToHMI" and another UDT for "FromHMI". Would I get the same performance from using a UDT like this compared to using a Dint[50]?

This way I can create a tag name for each function and I dont need to use bit and try to remember which one is which. I know the draw back from using UDT's is that you can modify them online.

You could also alias the bits so you don't have to remember which is which.

The only problem using an alias is that when the tags are used in factorytalk ME, you are using bits again.

Perhaps I don't understand exactly what you're saying, but you can reference aliases in FTView ME.

I never knew that...I'll have to try it.

Thx!

I'm thinking we are not on the same page with how to use an alias in this situation...

For example:

Declare an alias Pump101_Start for FromHMI[12].0.
Declare an alias Pump101_Stop for FromHMI[12].1.
Use Pump101_Start and Pump101_Stop in the ME application instead of FromHMI[12].0 and 1.
The data is still in the same place in the controllogix memory, you just access it by a different name.

All that being said, the value of grouping all your HMI tags into an array may not be as much as you think.

Back in the PLC5 and SLC500 days, blocking your addresses had a straightforward benefit for comms.
For example, if you had a bunch of references in the range N7:0 to N7:99, you would only need 1 packet for your comms. If you had N7:12, N7:142, N7:201, that would take 3 packets for only 3 references.

The controllogix is not so simple. There is still benefit to blocking HMI tags, but it's not as much as it was for PLC5. It all comes down to "make it easy to follow" vs. "make it as fast as possible". You have to decide which is more important.


P.S. Typing a long response sometimes means the conversation moves ahead while you are responding.