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CPU315-2 PN (Client) to Multimeters (Servers)

Created by: WildChild at: 2/3/2012 10:28 AM (5 Replies)

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2/3/2012 10:28 AM	Rate (0)
WildChild Posts: 26 Rating: (0)	Hello, I need to communicate CPU315-2 PN/DP cyclically with 3 multimeters by Modbus TCP/IP to read measurement parameters. I'm using the sample project MODBUS_PN_CPU_EXAMPLE (CPU319-3 PN/DP Client) but I have a few doubts: 1. How many calls to MODBUSPN do I need? 2. I configure the MODBUS_PARAM, with 3 different connections OUCW1, OUCW_2, and OUCW3. In the OB1 how can I access to the three connections?? I don't know how to make the requests for each server device. Thank u.
WildChild Posts: 26 Rating: (0)
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2/3/2012 11:12 AM	Rate (0)
Sakura Silver Member Joined: 9/22/2010 Last visit: 7/25/2024 Posts: 225 Rating: (28)	Hello WildChild, you need one MODBUSPN instance for each server. And each instance has to be called in OB100 and in OB1. Each connection OUCWx has its own connection ID. These are the same IDs that have to be configured in OB100. So you need to give each instance of MODBUSPN another ID in OB100. This is ID is stored during the initialisation process. And when you call MODBUSPN in OB1, it 'knows' which connection it has to use because the ID is stored in its instance DB. I hope what I wrote is comprehensible. Regards Sakura

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2/3/2012 11:33 AM	Rate (0)
WildChild Posts: 26 Rating: (0)	Thanx Sakura!! I think I'm beggining to understand. So...I need to call in OB1 and OB100 so many instanced MODBUSPN like different connections.Something like this? CALL "MODBUSPN" , "IDB_MODBUS_CON1" ... CALL "MODBUSPN", "IDB_MODBUS_CON2" ... CALL "MODBUSPN", "IDB_MODBUS_CON3" ... Do I need to declare one CONTROL_DAT for each connection too??
WildChild Posts: 26 Rating: (0)
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2/3/2012 12:03 PM	Rate (0)
Sakura Silver Member Joined: 9/22/2010 Last visit: 7/25/2024 Posts: 225 Rating: (28)	WildChild So...I need to call in OB1 and OB100 so many instanced MODBUSPN like different connections.Something like this? CALL "MODBUSPN" , "IDB_MODBUS_CON1" ... CALL "MODBUSPN", "IDB_MODBUS_CON2" ... CALL "MODBUSPN", "IDB_MODBUS_CON3" ... That's correct. In most cases Iwould recommend to have one CONTROL_DAT for each connection. Or you have one CONTROL_DAT with a STRUCT for each connection. It depends on you programm if you really need each parameter of CONTROL_DAT multiple times. For example you probably don't need the RECV_TIME and CONN_TIME 3 times, because in most cases they will have the same value. Do you send different requests to the servers? If you only send one request to all 3 servers, parameters like DATA_TYPE and START_ADDRESS don't need to be multiplied.

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2/3/2012 12:45 PM	Rate (0)
WildChild Posts: 26 Rating: (0)	Ok!! step by step... if I want to be cyclically sending request to the 3 devices at same time? OB1 Segm 1: CALL "MODBUSPN", "IDB_MODBUS_CON1" ... U "CONTROL_DAT_CON1".ENQ_ENR R "CONTROL_DAT_CON1".ENQ_ENR //for cyclic data exchange remove the comment keys -------------->> HERE I have removed the comment keys O "CONTROL_DAT_CON1".DONE_NDR O "CONTROL_DAT_CON1".ERROR S "CONTROL_DAT_CON1"ENQ_NDR ... Segm 2: CALL "MODBUSPN", "IDB_MODBUS_CON2" ... U "CONTROL_DAT_CON2".ENQ_ENR R "CONTROL_DAT_CON2".ENQ_ENR //for cyclic data exchange remove the comment keys -------------->> HERE I have removed the comment keys O "CONTROL_DAT_CON2".DONE_NDR O "CONTROL_DAT_CON2".ERROR S "CONTROL_DAT_CON2"ENQ_NDR ... Segm 3: CALL "MODBUSPN", "IDB_MODBUS_CON3" ... U "CONTROL_DAT_CON3".ENQ_ENR R "CONTROL_DAT_CON3".ENQ_ENR //for cyclic data exchange remove the comment keys -------------->> HERE I have removed the comment keys O "CONTROL_DAT_CON3".DONE_NDR O "CONTROL_DAT_CON3".ERROR S "CONTROL_DAT_CON3"ENQ_NDR ... Thank you very much for your help, It's my first attempt with Modbus TCP on Siemens.
WildChild Posts: 26 Rating: (0)
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2/3/2012 12:52 PM	Rate (0)
Sakura Silver Member Joined: 9/22/2010 Last visit: 7/25/2024 Posts: 225 Rating: (28)	Looks fine, that should work
	Last edited by: Sakura at: 2/3/2012 12:52 PM
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