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masterpact breaker

Created by: Ahmed.tn at: 9/22/2012 9:33 AM (9 Replies)

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9/22/2012 9:33 AM	Rate (0)
Ahmed.tn Bronze Member Joined: 11/10/2010 Last visit: 1/27/2025 Posts: 171 Rating: (9)	Helo, iI am trying to activate communication with breaker Masterpact of Schneider using a CP 341-RS422/485, it is possible to communicate with modbus several slaves at the same time? how to declare the Modbus address of slave device with which I want to read the books? thanx a lot

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9/22/2012 1:22 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 3/23/2025 Posts: 12344 Rating: (2707)	Hello Ahmed; You cannot talk to multiple slaves simultaneously, but you can talk to them one after the other. Remember that you need to set the Modbus Function parameters (different for each type of Modbus Function) in the Send Source DB. This is all well explained in the Modbus RTUmaster manual: SIMATIC S7-300/S7-400 Loadable Driver for Point-to-Point CPs: MODBUS protocol, RTU format, S7 is master The attachment shows the structure for the Send Source DB you will have to create for a Modbus Function 03 call (Read Output Registers, Modbus addresses 40000). So if you have more than one slave, do more than one call of the Send/Recieve functions, each with a different slave number in the first byte. If you want to call 2 different blocks of 40000 registers within the same slave, prepare 2 seperate Send/Recieve functions with different parameters for the start address and number of registers. Hope this helps, Daniel Chartier Attachment Send Source DB.jpg (120 Downloads)

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9/24/2012 11:25 AM	Rate (0)
Ahmed.tn Bronze Member Joined: 11/10/2010 Last visit: 1/27/2025 Posts: 171 Rating: (9)	helo, Dchartier I Thank You for the answer, I am trying to check the operation. I noticed that the send source DB is not called in the program, I wonder how it works!?

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9/24/2012 1:48 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 3/23/2025 Posts: 12344 Rating: (2707)	Hello Ahmed; There is a sample program for Mordbus RTUin chapter 9 of the manual I suggested earlier. This is a quote from that manual: The send data (SEND source area) are contained in DB 42. Data received from the link partner are entered into DB 43, the RCV destination area. Please study the sample program. The introduction of the Send DB in the Modbus FBs is shown in the attachment, also taken from the sample program. Hope this helps, Daniel Chartier Attachment Send_DB.jpg (110 Downloads)
	Last edited by: dchartier at: 9/24/2012 1:53 PM
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10/22/2012 6:02 PM	Rate (0)
Ahmed.tn Bronze Member Joined: 11/10/2010 Last visit: 1/27/2025 Posts: 171 Rating: (9)	Helo, about the source DB, how did I do to create it? because the DB already exists in the example does not look like the one on the picture for function code 03?! I have to create a new DB? if yes thank you to tell me the exact structure of the DB and what I need to change in function such that it works i always have this error code : 0E43 thank you

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10/22/2012 7:20 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 3/23/2025 Posts: 12344 Rating: (2707)	Hello Ahmend; In chapter 6 (Function Codes) of the Loadable Driver Modbus RTU master manual proposed earlier, you will find the complete and exact structure for the SEND source DB for every Modbus function code, and also the RCV Destination DB. Create a new pair ofDBs (SEND and RCV) for every request the master makes to a slave, based on the structure described in the manual.. In the application example, the SEND Source DB is DB 42. When you create a series of SEND source DBs for your own requests, use the numbers of the DBs you created for a specific Modbus Function, and insert the correct DB number in the call of FB 8, as shown in a previous screencapture when you are programming this Modbus Function call.. Hope this helps, Daniel Chartier

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10/24/2012 5:23 PM	Rate (0)
Ahmed.tn Bronze Member Joined: 11/10/2010 Last visit: 1/27/2025 Posts: 171 Rating: (9)	helo Mr Dchartier, thanx a lot for your help I'm doing testing on site, error code: is 0830H, I checked all the parameterization of modbus but still the same error code, do you know by chance what should I do? with best regards

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10/24/2012 6:12 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 3/23/2025 Posts: 12344 Rating: (2707)	Hello Ahmed; The error codes are explained in the manual proposed earlier 9see page 85, reproduced in the attached document). Validate your communication cable connection (pin by pin, see the diagram page 118 for RS-485 networks). If this is correct, check the other parameters as suggested. hope this helps, Daniel Chartier Attachment C:\Users\chard2\Pictures\ModbusMstr err 0830.jpg (111 Downloads)

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11/7/2012 9:53 PM	Rate (0)
Ahmed.tn Bronze Member Joined: 11/10/2010 Last visit: 1/27/2025 Posts: 171 Rating: (9)	helo Dchartier, I successfully communicate with a single slave and it works very well, the nightmare begins when I made a new call modbus functions with a different address to communicate with the second slave, so I recoi data from the first slave DB of the second and vice versa although I declared in two different DB function reception (DB destination). Have you had this problem already? best regards

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11/8/2012 12:20 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 3/23/2025 Posts: 12344 Rating: (2707)	Hello Ahmed; There are many, many threads on the subject in the forum. In this particular one you will find a project designed by member DR75 that might help you understand the mechanics of multiple slave polling with a Siemens Modbus RTUmaster: Multiple Modbus RTU slaves with CP341/CP441? Hope this helps, Daniel Chartier
	Last edited by: dchartier at: 11/8/2012 12:22 PM
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