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Connection to a fieldbus
6.3 Communication via PROFIBUS
Inverter with CU240B-2 and CU240E-2 Control Units
118
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
6.3.3.2
Data structure of the parameter channel
Parameter channel
You can write and read parameter values via the parameter channel, e.g. in order to monitor
process data. The parameter channel always comprises four words.
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Figure 6-3
Structure of the parameter channel
Parameter identifier (PKE), 1st word
The parameter identifier (PKE) contains 16 bits.
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Figure 6-4
PKE - 1st word in parameter channel
● Bits 12 to 15 (AK) contain the request or response identifier.
● Bit 11 (SPM) is reserved and is always 0.
● Bits 0 to 10 (PNU) contain parameter numbers 1 … 1999. For parameter numbers ≥ 2000
an offset must be added that is defined in the 2nd word of the parameter channel (IND).
The meaning of the request identifier for request telegrams (control → inverter) is explained
in the following table.
Table 6- 13 Request identifier (control → inverter)
Response
identifier
Request
identifier
Description
positive negative
0
No request
0
7 / 8
1
Request parameter value
1 / 2
↑
2
Change parameter value (word)
1
|
3
Change parameter value (double word)
2
|
4
Request descriptive element
1)
3
|
6
Request parameter value (field)
1)
4 / 5
|