How to use acyclic services?


I am new in the B&R world :slight_smile:
I am projecting some Controller that is also using acyclic services for parameter configuration.
there is access point fpr acyclic services on slot 2 subslot 1.
Siemens offers FBs like RdRec and WrRec for using this functions.
are there also some FBs in B&R World for that, or is the way different?

thanks a lot.


let’s start from the beginning.

Here you have in the help the function blocks to access to the parameters non-cyclical.
B&R Online Help (

AsIOAccWrite() and AsIOAccRead() probably are the ones that you need.

For example, a X20 analog card:
B&R Online Help (

You can modify, the configuration of the output (voltage or current only via Non-cyclic communication. And you can write it but not read)

Each channel has a bit.
B&R Online Help (

The most challenging part using the non-cyclical comunciation, with these functions is define properly the “pDeviceName”

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thanks a lot,
i will try my luck :slight_smile:

I have written a guide for easily determining the “pDeviceName”. Linking it here as it might be useful.