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Configuring the fieldbus
6.2 Communication via RS485
Frequency inverters with Control Units CU230P-2 HVAC, CU230P-2 DP, CU230P-2 CAN
Operating Instructions, 01/2011, FW 4.4, A5E02430659B AD
123
The length for the parameter channel is determined by parameter p2023 and the length for
the process data is specified by parameter p2022. If the parameter channel or the PZD is not
required, the appropriate parameters can be set to zero ("PKW only" or "PZD only").
It is not possible to transfer "PKW only" and "PZD only" alternatively. If both channels are
required, they must be transferred together.
6.2.2.5
Data structure of the USS parameter channel
The USS protocol defines for inverters the user data structure via which a master accesses
the slave inverter. The parameter channel is used to read and write parameters in the
inverter.
Parameter channel
You can use the parameter channel with a fixed length of 3 or 4 data words or with a variable
length.
The first data word always contains the parameter identifier (PKE) and the second contains
the parameter index.
The third, fourth and subsequent data words contain parameter values, texts and
descriptions.
Parameter identifier (PKE), 1st word
The parameter identifier (PKE) is always a 16-bit value.
3.(
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3:(
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318
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Figure 6-7
PKE structure
●
Bits 12 to 15 (AK) contain the request or response identifier.
●
Bit 11 (SPM) is reserved and always = 0.
●
Bits 0 to 10 (PNU) contain parameter numbers 1 … 1999. For parameter numbers
≥ 2000, you must add an offset in the 2nd word of the parameter channel (IND).
Содержание SINAMICS G120 CU230P-2
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