Siemens SINAMICS G120P, Руководство по эксплуатации

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Operation
6.8 Communication via RS485
Inverter cabinet units
Operating Instructions, 12/2014, A5E32923362A
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6.8.2.3 User data range of the USS telegram
The user data area consists of the following elements:
● Parameter channel (PIV) for writing and reading parameter values
● Process data (PZD) for controlling the drive.
Figure 6-14 USS telegram - user data structure
Parameter channel
In parameter p2023 specify the parameter channel length.
Parameter channel with fixed and variable length
● p2023 = 0
With this setting, no parameter values are transferred.
● p2023 = 3
You can select this setting if you only want to read or write 16-bit data or alarm signals.
● p2023 = 4:
If you want to read or write 32-bit values (for example indexed parameters or bit
parameters, e.g. r0722.2), then this setting is required. In this case, the send or receive
telegram always contains four words, even if only three would be required. The values
are entered right-justified in the 4th word.
● p2023 = 127:
If you set p2023 = 27 (variable length), the send and response telegrams are as long as
the task actually requires.
Process data
Parameter p2022 defines the length for the process data. You can transfer up to eight
process data items in one telegram (p2022 = 0 … 8). For p2022 = 0, no process data is
transferred.