Reading Data via Modbus TCP using FBD in Machine Expert

Hi all,
Has any of you got any example of reading data from modbus tcp, using FBD? I am just trying to get my head around, doesnt look like a problematic thing at all, but just need to do its the best possible way. I am actually new to FBDs, did this a while ago using ladder.

Thanks

I guess you have a M241/251/262 PLC and EcoStruxure Machine Expert (Codesys)
Do you want the PLC to be Modbus Client and read/write from/to a device acting as Modbus Server?

kallileo said:

I guess you have a M241/251/262 PLC and EcoStruxure Machine Expert (Codesys)
Do you want the PLC to be Modbus Client and read/write from/to a device acting as Modbus Server?

Click to expand...

Yes, have a M251 with ecostruxure machine expert. Yes, want to be reading/writing data to and from ABB’s switch for example?

It doesn't really matter if your are using FBD or Ladder.
Normally you set put Modbus channels and mapped them to variables. Then you can use the mapped variables directly in your code.

Check the following video
https://www.youtube.com/watch?v=FlC9yjWBAZQ

kallileo said:

It doesn't really matter if your are using FBD or Ladder.
Normally you set put Modbus channels and mapped them to variables. Then you can use the mapped variables directly in your code.

Check the following video
https://www.youtube.com/watch?v=FlC9yjWBAZQ

Click to expand...

Thank you so much!

@Kallileo, have you ever used ABB`s automatic switch? I essentially want to write some values to it, in order to make it switch (like switch the power source), but it looks like there is a complicated process to be followed to do that. Got any clues?

You mean Automatic transfer switch? Like the ones used to switch between mains and generator power sources?
I have not used it but it shouldn't be complicated.
Read the manual to find out which Modbus function codes the Modbus TCP server device supports.
For example if you want to write a single Holding Register you must use FC06 and for single coil FC05.

Experiment starting with setting up communication and then try to read some data.
When I use the device for the first time I start experimenting using a Modbus TCP Client on PC and only when I confirm that I read and write the correct registers from the device I setup the channels in the PLC.

Try first using the following tool first.
https://sourceforge.net/projects/qmodmaster/


https://www.csimn.com/CSI_pages/Modbus101.html