# Sfc 14 & sfc 15



## Abhi7288 (Jun 29, 2018)

ABB drive communicates through profibus to Siemens PLC and in plc programming sfc14 and sfc15 are used to read and write to drive. This is inbuilt object in PLC. Someone plz provide me how is communication performed. It is used in crane. I m providing the ladder programming. Plz help


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## gpop (May 14, 2018)

I dont understand your question. You know that blocks are being used to transfer data from the plc to the drive so what do you need to understand?


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## Abhi7288 (Jun 29, 2018)

gpop said:


> I dont understand your question. You know that blocks are being used to transfer data from the plc to the drive so what do you need to understand?


Actually I want to know what drive is sending as a command and where it is being stored. And what is received by drive. I mean address, values, etc. Is it int, Boolean, binary sequence. Is it stored in memory bit or DB. And if you can see there are 4 no of gears in the master controller. There is move block for each gear and the values are stored in DBs. Each move block is associated with 2000, 6000,12000 & 20000 respectively. What are these numbers. Plz explain


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## gpop (May 14, 2018)

The drive doesn't send anything. The plc requests data from a memory position on the com card. The com card gets data from memory position in the drive and nests them in a fomate that is capable of being transfered by the choosen network. It stores them in memory space ready for the request from the plc.
When you send a read request you get what ever is in the memory address. 

If you look at the drive manual or com card manual it lists what the words are used for. Some words are used at bit level to save netword band width which is why you assemble / disassemble the word back to bits in ladder logic.
Maybe some one else can explain it better. Generally if you have the ladder logic and a vfd/com card manual you can see whats being moved backwards an forwards. You can also go to the drive and look under parameter numbers to see the data


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## Abhi7288 (Jun 29, 2018)

Can anyone explain the ladder logic program, I mean each network. There are 12 networks in the ladder logic


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