12/3/2020 7:57 AM | |
Joined: 4/25/2017 Last visit: 10/11/2024 Posts: 430 Rating: (66) |
Hi, Maybe this example will help you How do you establish a MODBUS-RTU communication with STEP 7 (TIA Portal) for the SIMATIC S7-1200? On the bottom of this page are also some other links. |
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This contribution was helpful to1 thankful Users |
12/5/2020 11:33 AM | |
Posts: 7 Rating: (0) |
Unfortunately, I didn't find anything for myself from your link. Either I don't understand the information. Can anyone else suggest other solutions? |
12/5/2020 3:00 PM | |
Joined: 9/27/2006 Last visit: 10/17/2024 Posts: 12289 Rating: (2687) |
Hello Andry; Reading and writing to multiple Modbus RTU slaves is simply a question of handling the sequence of Modbus jobs, using the signals from the Modbus master functions, DONE and ERROR. Since exchanging data with 2 slaves implies 2 different MB_Master blocks, exchanging with 5 slaves means 5 locks sequenced so that they do not compete with each other ( ex.: wait for the DONE signal of your first block before you start the second one...).. Here are a few examples from the forum, there are many more you can search for using the search box at the right of this forum page: - S7 1200/S7-1500 As Modbus RTU Master Write To 5 Modbus Slaves - Modbus RTU Multiple slave reading Hope this helps, Daniel Chartier |
12/5/2020 11:01 PM | |
Joined: 2/22/2016 Last visit: 10/6/2024 Posts: 141 Rating: (30) |
Hi Andry ! Reading data from more then one devices isn't actually match difference then reading more then one section of data from one device. I made a modbus library that is particular useful when doing modbus rtu with several devices. Without the library you need a sequence loop as Dchartier describe, where each step read or write data to or from each device. If you chose to go for the library approach I am standby if you need help. https://github.com/rexhip/rexhip Kind regards Attachmentmodbus_lib_3.4.0.zip (687 Downloads) |
Please use the contact form in the link below if you will like to come in contact with me. I don't check personal messages frequently. |
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