s7-1200 ASCII advice

Hi!

A customer has a weighing machine and wonder if he can read the results thorugh their communication port. I have never done ASCII before and have a few questions.

They state that the communication is:

Baudrate 9600
Databits 8
Parity None
Stopbits 1

Protocoll is ASCII based

They don't state what connection they send it through they just say it's a "COM PORT". Musn't I know this too? To know what module I have to buy to the s7-1200 to recieve the signal?

They say the protocoll is ASCII based, what does that mean? Is ASCII a protocoll of it's own or do I send it over for example modbus?

The data to be sent is in this format:

weigh+c+cr+if

I guess this is some sort of information, I will have to ask them some more of what it contains.

And last, what block in TIA portal is used to get ASCII from a slave?

You need to know what format. Assume RS232. CM 1241 Module.
ASCII is a standard RS232 protocol. Simply put, it just means "text".

Setup in TIA.

It could potentially be RS485 as well, but I think RS232 is probably the most likely.

Phoenix Contact has a FL-COM server that can convert RS-232 / 485 etc... to Ethernet. Then you could just connect to the FL-COM server via TCP/IP and received the data way.

I prefer to deal with data at the PLC as TCP/IP instead of serial.

The only thing to watch out for this route is that you have the proper serial cable (straight through / null modem) but I guess that issue will exist either way.

You need to know the weighing machine specifics. Then search for the manual on the weigh machine. It should show you the protocol of the unit.

weigh+c+cr+if (CR - carriage return, LF - Line feed)

This is good but you need to know if you must send it a command to start communication or will it be sent automatically.

ASCII - American Standard Code for Information Interchange

Hope this helps,
Garry
http://www.accautomation.ca

Thanks alot for usefull information guys. Now I have better understanding and can give my customer a price indication on the project ! I 'll let you know if I run in to more trouble.

Thanks /Tim