Best way to historise a bit of an integer defined in a UDT

Ignition
1

Hi All.

Ignition 8.1.14 running on windows server 2019.

Just wondering what is the best way to historise a bit within an integer “status” word when the tag is defined in a UDT.

Should I just add derived/expression tags (in the UDT definition) for each of the bits I’m interested in or is there a much better way of doing it?

Regards
Dave

2

If the source is OPC, I’d be inclined to add the bit reference to another OPC tag. If any other type, I’d use an expression tag.

3

Thanks Phil.

I went with the expression tag as there are 20+ bits in the dint (6 of which need to be trended).
I imagine 20 OPC tags to bits of the DINT is more costly on comms than just reading the DINT once and creating expression tags (which I guess will depend on the grunt of the server processor)

Regards
Dave

4

No, OPC drivers are generally smart enough satisfy those together as long as they are subscribed at the same pace. That's why I recommended it.

5

Thanks Phil

Useful information to know

Regards
Dave