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Help Modbus

Created by: kristine at: 5/6/2009 3:14 PM (34 Replies)

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5/12/2009 11:02 AM	Rate (1)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi, okay, if the PLC should be the modbus client: In OB100 In OB100 you have to give the initialisation parameters. It makes no sense to give the runtime parameters in OB100. And the incrementation of DONE_NDR counter and TI is senseless in OB100 as well. ENQ_ENR is not an initialization parameter and so you don't need to set or reset ENQ_ENR in OB100. Change it as follows: SET = "CONTROL_DAT".ENQ_ENR //job trigger CALL "MODBUSPN" , "IDB_MODBUS" ID :="CONTROL_DAT".ID DB_PARAM :="MODBUS_PARAM" RECV_TIME :="CONTROL_DAT".RECV_TIME CONN_TIME :="CONTROL_DAT".CONN_TIME KEEP_ALIVE := ENQ_ENR :="CONTROL_DAT".ENQ_ENR DISCONNECT :="CONTROL_DAT".DISCONNECT REG_KEY :="License DB".REG_KEY LICENSED :="CONTROL_DAT".LICENSED BUSY :="CONTROL_DAT".BUSY CONN_ESTABLISHED:="CONTROL_DAT".CONN_ESTABLISHED DONE_NDR :="CONTROL_DAT".DONE_NDR ERROR :="CONTROL_DAT".ERROR STATUS_MODBUS :="CONTROL_DAT".STATUS_MODBUS STATUS_CONN :="CONTROL_DAT".STATUS_CONN STATUS_FUNC :="CONTROL_DAT".STATUS_FUNC IDENT_CODE :="CONTROL_DAT".IDENT_CODE UNIT :="CONTROL_DAT".UNIT DATA_TYPE :="CONTROL_DAT".DATA_TYPE START_ADDRESS :="CONTROL_DAT".START_ADDRESS LENGTH :="CONTROL_DAT".LENGTH TI :="CONTROL_DAT".TI WRITE_READ :="CONTROL_DAT".WRITE_READ ~~U "CONTROL_DAT".ENQ_ENR~~ ~~R "CONTROL_DAT".ENQ_ENR //reset trigger after job has started~~ L 500 T "CONTROL_DAT".RECV_TIME L T#5S T "CONTROL_DAT".CONN_TIME UN "CONTROL_DAT".ERROR BEB L "CONTROL_DAT".STATUS_CONN T "CONTROL_DAT".Save_STATUS_CONN //for static display in VAT L "CONTROL_DAT".STATUS_MODBUS T "CONTROL_DAT".Save_STATUS_MODBUS //for static display in VAT // STATUS_FUNC => Save_STATUS_FUNC L DB1.DBD 38 T DB1.DBD 92 L DB1.DBD 42 T DB1.DBD 96 L DB1.DBW 46 T DB1.DBW 100 Delete all other lines in your OB100 below the modbus block. In OB1 Delete following lines in the OB1: SET = "CONTROL_DAT".ENQ_ENR //job trigger You can't start 1 telegram in each cpu cycle. You can start an order/telegram with ENQ_ENR = TRUE and after that you have to wait that the order is finished with ERROR = TRUE or DONE_NDR = TRUE. If one of these bits was set, then you can start the next order/telegram with ENQ_ENR = TRUE. It's wrong to set this bit in each cycle. Load the changed program in your plc and try it again. In the VAT you can start a telegram with ENQ_ENR = TRUE. You could implement this in OB1 as well, but you have to wait for the completion of the previous order! Wüstenräuber

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This contribution was helpful to 1 thankful Users kristine

5/13/2009 9:42 AM	Rate (0)
kristine Posts: 17 Rating: (0)	Hello Wustenrauber Thanks for your help i will try as you describes and try it again. Thanks and Regards Kristine
kristine Posts: 17 Rating: (0)	Last edited by: kristine at: 5/13/2009 10:04 AM
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5/13/2009 10:00 AM	Rate (0)
kristine Posts: 17 Rating: (0)	Hello Wustenrauber I am waiting for you reply. Regards Kristine
kristine Posts: 17 Rating: (0)
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5/13/2009 10:04 AM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi, I don't understand you. My reply is above (yesterday:5/12/2009, 11:02 AM). Wüstenräuber

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5/19/2009 10:07 AM	Rate (0)
kristine Posts: 17 Rating: (0)	'hello Wustenrauber, Thank you very much for you previous help,it worked perfectly for us. I am able to receive data from our simulator. But i have a little problem,i want to send that data i received from simulator to the operator panel on another PC, i have called modbus pn twice in OB1 and OB100,with a new PARAM_DB with new connection paramteres, i think i have a mistake when calling the second MODBUS PN,can you please make a example code of 2 connections in our program which i sent to you,i am just confused about the sequence of instruction. It will be very kind of you. Thanks and Regards Kristine
kristine Posts: 17 Rating: (0)
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5/19/2009 1:08 PM	Rate (1)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi Kristine, you want to read and write datas to the same communication partner, but S7 is the client in both cases? If yes, then you don't need 2 instances of the modbus block. You set START_ADDRESS, LENGTH and DATA_TYPE and start a telegram for reading (READ_WRITE = FALSE).If DONE_NDR or ERROR is set to TRUE, then you change START_ADDRESS, LENGTH and DATA_TYPE and start a newtelegram for writing (READ_WRITE = TRUE). If DONE_NDR or ERROR is set to TRUE, you can change the runtime parameters for your next telgram and so on. This you have to implement in your logic in PLC and it's the easiest way torealize a reading and writing function. Wüstenräuber

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5/19/2009 1:16 PM	Rate (0)
kristine Posts: 17 Rating: (0)	Hello, Thanks for replying. I have to different communication partners with PLC.1- Simulator,2-Operator Panel. We want to read data from Simulator , Process it and send it to Operator Panel and same in the opposite direction, from operator panel to PLC and from PLC to Simulator. S7 is client in all cases and the other PCs with simulator and operator panel are Servers. What i have to do in this case Regards Kristine
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5/19/2009 2:39 PM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi kristine, okay. Do following: 1) Copy the parameter DB MODBUS_PARAM and change the parameters with the Modbus Wizard: ID and the ip address of the communication partner. 2) Open OB100 and call the modbus block with a new instance DB. Parameterize the instance_DB (new parameter DB etc.). 3) Open OB1 and call the modbus block with the same (new) instance DB and set the runtime parameters. Good luck. Wüstenräuber

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5/21/2009 5:57 PM	Rate (0)
kristine Posts: 17 Rating: (0)	Hello again, Thank you very much for your help. Everything you told us, worked perfectly. There is still a little problem in our program. We are able to receive data from PC1 to PLC and we are abli to forward it from PLC to PC2, But problem is that we cannot send data from PLC to PC1,we have tried many combinations of fuction codes but it did'nt work. If you want so i can send you a copy of my program so that you can check what is probelm in that. Thanks and Regards Kristine Pettersen
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5/21/2009 8:25 PM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi kristine, which errorcode occurs? Send the project to the moderator again. Wüstenräuber

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