You are not registered yet. Please click here to register!

plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
Try our online PLC Simulator- FREE.  Click here now to try it.

---------->>>>>Get FREE PLC Programming Tips

New Here? Please read this important info!!!

Go Back - Interactive Q & A > - Interactive Q & A > LIVE PLC Questions And Answers

PLC training tools sale

Thread Tools Display Modes
Old July 21st, 2014, 09:51 PM   #1
United States

surajchem is offline
Join Date: Apr 2012
Location: houston
Posts: 15
S7-1500 CM541 Serial RS232 ASCII help

Hi All,
I have worked with Modbus communication before, but this is my first time with Serial ASCII. I am not sure how to process it. I was wondering if someone could show it with an example.
I have S7-1400 with 2 CM541 basic comm module. They each talk to a scale device which send out the following ASCII message via RS232.
where STX is start of the message, POL is + or -, DATA is Six char showing wt in real value, SP is space, lbs is unit, ST is status.
I know that I have to setup the start of message as STX and end of message as CR and LF (4th and 5th end char) in the hardware config. I was trying to use Recieve_P2P function block. But i am not sure what should be buffer data type be.
a) should it be an array of 20 char or so with buffer pointing to P#DB1.DBX0.0 Byte 20 .
or b) string of lenght 22 with pointer pointing to the 3rd element of the string.

I just want to display the weight i.e POL and DATA in HMI.
How should i proceed?
I would appreciate all the help.
Thank you.
  Reply With Quote
Jump to Live PLC Question and Answer Forum


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
s7 1500 cant connect to wincc scada Blue Fox LIVE PLC Questions And Answers 1 October 3rd, 2013 06:32 AM
s7 200 and printer SHYAMAL LIVE PLC Questions And Answers 6 August 12th, 2008 01:47 AM
RS232 9th Bit Interrupt Support In S7 arc LIVE PLC Questions And Answers 2 July 22nd, 2005 01:01 AM
Communicating in RS232 or 485 with S7 Johnny T LIVE PLC Questions And Answers 5 June 30th, 2005 03:54 PM
Serial RS232 connection with RSLogix 500 pado75 LIVE PLC Questions And Answers 6 March 27th, 2003 08:39 AM

All times are GMT -5. The time now is 02:53 PM.