RS232 ASCII, trouble getting HEX data

Ken Roach said:

drbitboy, you read correctly that the word "good" was significantly modifying the phrase "no workarounds". ...

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Yah, if I had this handed to me, with a small capital budget, and where my time was properly valued, I might consider tossing the -232ASC and implementing the RS-232 interface and data parsing in a RaspberryPI for all of maybe $50-100 in parts, which would be all but trivial in this case, and then have that communicate with the PLC over ethernet, plopping the data into some tags that the PLC could check every scan, no PLC TONs and the rest of the schlock required. To be sure that's a rube goldberg/heath robinson approach, but I suspect coding anything like this properly in a PLC is painful, even if with the right interface card.


Maybe the HMS AB7072 you suggest does summat similar?

drbitboy said:

Maybe the HMS AB7072 you suggest does summat similar?

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not similar, better:

They are pretty nice to use on weird stuff. You can define a serial protocol and have the unit decode and encode to it and transfer the data to/from the PLC.

The HMS "Anybus Configuration Manager" utility is very good and mature, on par with Prosoft Configuration Builder.

The AB7072 is the model number for the mature EtherNet/IP to Serial gateway. It has some wizards to set it up for DF1 or Modbus RTU.

In this application, it looks like the serial poll has a straightforward format with a fixed first byte (0x41 = "A") followed by a two byte command, followed by a 1-byte checksum.

The check sum is the sum of the bytes after "A", XOR'ed with 0xFF. That's about the simplest checksum there is.


The only thing I'm not sure of is how to tell the Communicator how to handle the different-length responses. The Length is explicit in the third byte of the response (01 or 04 in these examples).

The easy thing would be to use separate Transactions for the commands that give a 1-byte response and the ones that give a 4-byte response.

Thank you guys for your help and support...

• drbitboy
  Geoff White
  Ken Roach

Ill try to get the device as Ken suggested, then I will update this post.

thank you very much.....gracias señores

just to update this post.:site:
I got this thing working using the AnyBus Communicator AB7072-B (Thanks Ken R.).
works really good and it is easy to set up (after few tries).
Also I got the Mantissa working as it should.
I uploaded a video to youtube to show how it works, if web link is not allowed please remove or let me know and Ill remove it. (www.youtube.com/watch?v=P9wARQKlEB4&t=202s)

Thank you all for your help.

da nada.


Great music.


I didn't see the decode of the mantissa, but the result looks correct (DINT 111... yields REAL 60....).


Sweet!

drbitboy said:

da nada.


Great music.


I didn't see the decode of the mantissa, but the result looks correct (DINT 111... yields REAL 60....).


Sweet!

Click to expand...

Sorry i'll add the mantissa code to the video....Thanks.....Gracias