PROFIBUS Manual
The compact format is always described with one byte. Byte coding for the compact format is as follows:
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
Configuration: compact format |
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0 |
1 |
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|
|
Input |
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1 |
0 |
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Output |
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1 |
1 |
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Input & Output |
0-15
|
Length of data 00 = 1 byte or word 15 = 16 bytes or words |
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1 |
Word(s) of 16 bits |
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0 |
Bytes of 8 bits |
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1 |
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Consistency across the entire module |
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0 |
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Consistency across one byte or one word |
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An identifier for a compact format module can therefore comprise up to 16 bytes or 16 words. One word is made up of 16 bits.
The consistency indicates to the DP master (controller) how data is used: whether these bytes or words can be interpreted individually, or whether they always have to be processed as a whole. It is the task of the DP master to ensure the required consistency.
Examples for compact format module coding:
| 0x11 = | 2 byte inputs - consistency per byte |
| 0x22 = | 3 byte outputs - consistency per byte |
| 0xF3 = | 4 word inputs and outputs - consistency across the entire module |
0x71 = 2 word inputs and outputs - consistency per word
