Uss Parameter Channel - Siemens SINAMICS G120 Operating Instructions Manual

Parameter channel
In parameter p2023 you specify the parameter channel length.
Parameter channel with fixed and variable length
● p2023 = 0
● p2023 = 3
● p2023 = 4:
● p2023 = 127:
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.
7.7.2.4

USS parameter channel

Structure of the parameter channel
Depending on the setting in p2023, the parameter channel has a fixed length of three or four
words, or a variable length, depending on the length of the data to be transferred.
1. and 2nd word contain the parameter number and index as well as the type of job (read or
write). The other words of the parameter channel contain parameter contents. The
parameter contents can be 8-bit values, 16-bit values (such as baud rate) or 32-bit values
(e.g. CO parameters). The parameter contents are entered right justified in the word with the
highest number. Words that are not required are assigned 0.
Bit 11 in the 1st word is reserved and is always assigned 0.
The diagram shows a parameter channel that is four words long.
You can find examples of telegrams at the end of this section.
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB
With this setting, no parameter values are transferred.
You can select this setting if you only want to read or write 16-bit data or alarm signals.
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 enter right-justified in the 4th word.
If you set p2023 = 27 (variable length), the send and response telegrams are as long as
the task actually requires.
Configuring the fieldbus
7.7 Communication via RS485
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