6/15/2011 7:02 AM | |
Posts: 28 Rating: (0) |
we have a CPU224XP as slave that has Modbus communication and recieved some hardwire Digital inputs and want send them via Modbus to master.how can I do this? |
6/15/2011 7:23 AM | |
Joined: 10/7/2005 Last visit: 9/21/2024 Posts: 3021 Rating: (1054) |
Hello zmzm a simple search at https://support.automation.siemens.comrevealsthe following FAQ's and I hope it helps: How do you implement MODBUS communication with S7-200? Where in STEP 7 Micro/WIN can I find the operations libraries for the Modbus RTU protocol and USS protocol? Definition of variables of the USS and MODBUS library P.S: There's a fair few Forum dicussions available on this subject too which can be found with the same search. |
Cheers |
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6/15/2011 7:52 AM | |
Joined: 3/21/2006 Last visit: 9/10/2024 Posts: 10228 Rating: (1181) |
Hello, How do you implement MODBUS communication with S7-200? Best regards, Hristo MIhalev |
6/15/2011 9:05 AM | |
Joined: 4/24/2006 Last visit: 9/20/2024 Posts: 8742 Rating: (1168) |
Dear zmzm, Here is link to manual: S7-200 System manual See chapter 12 for more information about Modbus communication. If you are a Modbus slave, you only have to use the mentioned blocks. The master will ask the Hardwired inputs by using the right Modbus Addressing (Modbus address 10001 till 10128 Best regards, Wizard |
6/15/2011 11:27 AM | |
Joined: 3/18/2008 Last visit: 12/8/2023 Posts: 1750 Rating: (272) |
Dear Zmzm, Little addition.. you also need modbus library for modbus communication. Have a look at following FAQ. Where in STEP 7 Micro/WIN can I find the operations libraries for the Modbus RTU protocol and USS protocol? |
Last edited by: Amit_86 at: 6/15/2011 11:28 AMVANDE MATARAM..... |
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7/18/2011 7:51 AM | |
Posts: 9 Rating: (1) |
Dear Wizard, Is it that simple? just to use the block in the Modbus library; MBUS_INIT and MBUS_SLAVE and the rest is up to the master? ><" how about when receiving write instruction from master? is it the same? if so, the slave will only contain the block MBUS_INIT and MBUS_SLAVE and nothing else? correct me if im wrong, so the modbus address mapping is already fix 00001-00128 are discrete outputs mapped to Q0.0-Q15.7 10001-10128 are discrete inputs mapped to I0.0-I15.7 30001-30032 are analog input registers mapped to AIW0-AIW62 40001-4xxxx are holding register mapped to V memory So the only thing we can change is the holding register V memory base on the HoldStart in MBUS_INIT?
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2/24/2015 3:08 PM | |
Joined: 9/3/2014 Last visit: 3/13/2019 Posts: 4767 Rating: (123) |
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10/2/2015 1:20 PM | |
Joined: 9/3/2014 Last visit: 3/13/2019 Posts: 4767 Rating: (123) |
New question published by U_636e5741-31e4-422f-a108-945962a9e016 is split to a separate thread with the subject 226-cn CPU fetch data directly from SCADA. Best regards |
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