Profibus communication between PMA and Siemens

Kataeb · Mar 24, 2009

I am interfacing KS800-DP modules (temperature controller made by PMA) with SIEMENS S7-317 2DP CPU, using PROFIBUS DP Communication.
The GSD file for the KS800-DP is installed and the hardware configuration is ok.
But the problem is with the “Process data” communication: I am unable to read and write values in sequence using SFC14 and SFC15. I cannot be read with the same SFC14 more than one byte. I have to call SFC14 each time for every byte alone.
I tried another way: read/write directly in the peripheral memory, but also it is working for each byte alone.
The telegram to transfer the process data is really long (66 bytes inputs and 52 bytes outputs), and I do not want to write a line for each byte (I have 5 controllers!).
Is there a way to use pointers to access these data sequentially?

Thanks

JesperMP · Mar 25, 2009

SFC14 and SFC15 should work with 3 bytes or 5 bytes or more.
1, 2 and 4 bytes shall be accessible with regular i/o addressing.

So it makes very little sense that you cannot get it to work.

How does your code look like ?
What is the status message from SFC14 or SFC15 ?

Kataeb · Mar 25, 2009

the PMA have specific data types (some are bytes, others words or dword,...). this means that if the transmitted data type is word, we cannot read it as byte or 4 bytes, only as 2 bytes.
so we tried to do indirect addressing as follows, and now it is working ok. thank you anyway.

input
L P#256.0 // load PIW 256
LAR1
L PIW [AR1,P#0.0]
T MW xxx ( DBxx.DBW xxx) // Transfer to xxx

output
L P#256.0 // transfer to PQW 256
LAR1
L MW xxx ( DBxx.DBW xxx) // Value for Output
T PQW [AR1,P#0.0]

JesperMP · Mar 25, 2009

If you are transferring the data word for word like that, you could just write:

L PIW256
T MW100

L MW200
TPQW256

Kataeb · Mar 25, 2009

Yes, but i have 5 controllers with 66 bytes inputs and 52 bytes outputs each. So I will have to write hundreds of lines in the program. That is why I preferred indirect addressing.
Thanks

JesperMP · Mar 25, 2009

OK, in your example there was no indexing. Never mind.

JesperMP · Mar 25, 2009

Actually, if the inputs and outputs are arranged in large contigous blocks, then I cannot see why SFC14 and SFC15 shouldnt work.

I am guessing that you need to setup all the data from each controller as consistent contigous.
The SFC14 and SFC15 calls must match exactly the consistent contigous data areas.
All DP slaves have a slightly different setup dialog. But I am guessing this setting is in there somewhere.

Profibus communication between PMA and Siemens

Kataeb

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JesperMP

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Kataeb

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JesperMP

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Kataeb

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JesperMP

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JesperMP

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