4/20/2015 4:46 PM | |
Posts: 20 Rating: (1) |
Hi people I need your advice I have a S7-1217C that I want to connect to 9 drives(Optidrive Invertek) in order to read 6 registers and write 2 in each drive. The communication is done with a CM 1241 (RS422/RS485) So far I have implemented the Modbus read and write functions but I'm concerned about the CPU cycle time which is now around 1140ms with ONLY ONE DRIVE! My approach: 1- Configure the MODBUS communication at Startup (OB100). 2- Call my CONTROL_DRIVE FB in OB1. There 8 cases are defined: 6 of them call the MB_READ FB and 2 of them the MB_WRITE FB. In each case I supply to the MB_MASTER function the parameters for reading or writing the register. 3- In MB_READ and MB_WRITE FBs the MB_MASTER is executed with the proper parameter. The same instance data block(MB_MASTER_DATA_PUMP) is used both, for reading and writing registers. All these steps work, but as I said the cycle time is around 1140ms. I was planning to add DRIVE2_READ/ DRIVE2_WRITE ..to DRIVE9_READ/DRIVE9_WRITE but I want to know from you if that is a good approach or whether I should do it in another wiser way. Thank you I leave some screen shoots. By the way I already checked the link "How do you establish a MODBUS-RTU communication with STEP 7 (TIA Portal) for the SIMATIC S7-1200" |
4/20/2015 4:48 PM | |
Posts: 20 Rating: (1) |
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4/20/2015 4:49 PM | |
Posts: 20 Rating: (1) |
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4/20/2015 4:50 PM | |
Posts: 20 Rating: (1) |
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