Siemens S7 Driver Bytes to Bits

Ignition
1

Hi,

I have a project where we are converting a legcay SCADA system to Ignition, the controllers they are using are Siemens S7-300s. The tags are being packed into DBs and transferred across in byte arrays.

My question is what is the most efficient/cleanest way to unpack those bytes into bits within Ignition?

What I have done is create expression tags that reference the byte using the getBit function and unpack them that way.

The other way would be to just reference the bit directly in the OPC item path DB120,B582.1, but will this put more traffic on the controller?

Any suggestions? Cheers.

2

Follow the normal route for Booleans. Expression tags are read only, messy and unnecessary.
The Siemens driver can optimise for the communications side.

1 Like
3

Thanks Dave!