Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

CP341 communication via RS485

Created by: Meritor at: 8/20/2008 9:26 PM (4 Replies)

Rating (0)

Thanks 0

5 Entries

8/20/2008 9:26 PM	Rate (0)
Meritor Posts: 33 Rating: (2)	Dear All, I need to communicate with a Scale via RS485. The Scale is only able to send data I decided to use CP341 card but I never done this before. Some information about the communication method: 1. Port settings: RS485, 9600 baud, 8 data-, 1 stop bit, no parity 2.Scale Protocol: [STX]xxxxx[SUM][ETX][CR][LF] - [STX]: STX character (decimal 02) - [ETX]: ETX character (decimal 03) - [CR]: CR character (decimal 13) - [LF]: LF character (decimal 10) xxxxx: Weight of Tank in Kg (5 characters), using space from left if needed [SUM]: check sum character for the weight above e.g.: [STX]12340[250][ETX][CR][LF] 12340 kg SUM=(49+50+51+52+48) mod 256 = 250 [STX] 0[176][ETX][CR][LF] 0 kg SUM=(32+32+32+32+48) mod 256 = 176 3. We should only use receive function as the Scale has no receiving function. It is only able to send infromation. 4. The scale is going to send infromation 10 times per second! Can you help me how to make this protocol in Step7? Can you supply any sample project? Norbert
Meritor Posts: 33 Rating: (2)	Last edited by: Meritor at: 8/20/2008 9:30 PM
Suggestion To thank Quote Answer

8/21/2008 9:51 AM	Rate (0)
jklm Platinum Member Joined: 12/22/2006 Last visit: 1/25/2022 Posts: 1742 Rating: (309)	Hello, Seems me to be a pure ASCII echange. You may recompute the checksum in your program if you want (if a wrong value is critical). When you install the configuration software for CP PtP (http://support.automation.siemens.com/WW/view/en/27013524) there are sample programs installed at the same time. In Step7 ==> File ==> Open. But you choose now the TAB "sample programs". And you will see a project "zxx21_01_PtP_com_CP34x" In this projects, several samples, one is an ASCII sample. Good luck
	Best regards jklm Suggestion was helpful? Feel free to rate it.
Suggestion To thank Quote Answer

8/22/2008 10:51 AM	Rate (0)
Meritor Posts: 33 Rating: (2)	Hi, I have downloaded the file above and open the sample project. I could find 5 sample project in it? Can you tell me which one is fit to my issue? I assume that the Protocol3964 no, I also assume that the V24 and RK512 is also not... So what should I use to make this project real? Thanks,
Meritor Posts: 33 Rating: (2)
Suggestion To thank Quote Answer

1/21/2009 9:22 PM	Rate (0)
Late Platinum Expert Joined: 1/7/2006 Last visit: 12/23/2024 Posts: 2705 Rating: (320)	Dear Meritor, Please look to the example: reading three length measurements (Strings) into the CP340 via an ASCII protocol And please fill in the data that you need.
	I hope that the answer will help, if you have still questions, don't hesitate to ask me. All the best, Late Never say never, think in solutions, not in trouble......
Suggestion To thank Quote Answer

2/2/2009 6:22 PM	Rate (0)
PaddyW Posts: 1 Rating: (0)	Dear Late I am also trying to use RS232 to get data into a CP341. I download the file as you suggested but the sections that need to be adjusted are know how protected. How can i get a copy that is not protected. Best Regards PaddyW
PaddyW Posts: 1 Rating: (0)
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on