12/19/2020 3:38 PM | |
Joined: 9/27/2006 Last visit: 9/16/2024 Posts: 12282 Rating: (2683) |
Hello sander; Welcome to the Siemens automation forum. To be able to answer your questions we will need a bit more information on your project, and on your familiarity with PLCs and communications. There are a few things we need to think about before you can proceed. You have a weighing station with RS 232C capabilities. We would need to know what make and model, so we can look for the communication parameters of this unit. Just as an example, the Wago 750-660 RS-232C module supports only one set of parameters, as you can see in this manual: - Wago 750-650 RS 232C interface:manual: https://www.wago.com/global/d/1609 Important:note from the manual: The data transmission takes place at 9.600 baud. 1 startbit, 8 databits and 1 stopbit will be transmitted. No parity is available So we need to know the details of the weighing station communications configuration to check whether this Wago module is compatible. There are other modules available from Wago that match other parameter sets. .Next, we need to know how the data sent by the weighing station is encoded. Is it ASCII format, raw data telegram, etc... This will determine if your CPU can easily make sense of the data it receives from the unit. Following these details we have to examine how your RS 232C module is physically set up. The 750-660 is simply a communication module, it requires a power source and a PLC or coupler to operate properly. Do you have a Wagp PLC that it can connect to, or a communication coupler that can link it to the S7-400 CPU (Profibus-DP or Profinet)? This is a minimum requirement (with a mounting rail), if Wago is the way you choose for your project. Here is a link to download the manual for the 750-333 Profibus-DP coupler, one of the various Profibus couplers from Wago that you could choose: - Wago 750-333 Profibus coupler manual and link to demo from Youtube:: https://www.wago.com/global/d/1587 https://youtu.be/8yguvisZ9d0 Another option would be to use a CP 441-2 (serial processor) on the S7-400 rack, with a RS 232C interface module, to connect your S7-400 directly to the weighing module (we still need this unit's communication information for this setup....) CP 441-2 serial processor for the S7-400 CPUs : - 6ES7441-2AA03-0AE0: SIMATIC S7-400, CP 441-2 SIMATIC S7-400, CP 441-2 COMMUNICATIONS MODULE FOR POINT TO POINT CONNECTIONS 2 CHANNELS INCL. CONFIG. PACKAGE ON CD - 6ES7963-1AA10-0AA0: INTERFACE MODULE IF963-RS232/CP 441 SIMATIC S7-400, interface module IF963-RS232 with RS232 interface for PTP coupling with CP441 AB CP 441- AA05 - Data Transmission with the RS 232C ASCII Driver https://support.industry.siemens.com/cs/ww/en/view/1137419/35746003979 Hope this helps, Daniel Chartier |
2/2/2021 10:04 AM | |
Joined: 12/19/2020 Last visit: 8/26/2024 Posts: 6 Rating: (0) |
Hello Daniel, thank you for your detailed information. At that we moment we had to use another solution. We still want to try test if we can use this with the wago. So a the answers to you questions; I am pretty new to Siemens and have experience with Beckhoff PLCs. We are using a Wipotec IW8k I attached the manual. The manual tells this about the communication. We are using the similar weight cells with Beckhoff and RS422. Here we send commands like "G20" to get a weight. At this PLC we don't have a remote IO station but we do have the wago 750-303 profibus coupler. Can you tell with this information if it is possible to communicate with the weight cell? If possible which fb/fc can we use for this communication. regards, Sander AttachmentDoku-IW - 29_01_02_e.pdf (351 Downloads) |
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