Communication processor and Modbus TCP
12.4 Universal serial interface (USS) communication
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
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Table 12- 34 Calculating the time requirements
Calculated minimum USS_PORT call
Interval ( milliseconds )
Drive message interval timeout per
drive ( milliseconds )
USS_PORT (Edit communication via USS network) instruction
Table 12- 35 USS_PORT instruction
PORT:=_uint_in_,
BAUD:=_dint_in_,
ERROR=>_bool_out_,
STATUS=>_word_out_,
The USS_PORT instruction handles communication
over a USS network.
Table 12- 36 Data types for the parameters
PORT IN Port After you install and configure a CM or CB communication device, the
port identifier appears in the parameter helper drop-list available at the
PORT box connection. The assigned CM or CB port value is the device
configuration property "hardware identifier". The port symbolic name is
assigned in the "System constants" tab of the PLC tag table.
The baud rate used for USS communication.
USS_DB INOUT USS_BASE The name of the instance DB that is created and initialized when a
USS_DRV instruction is placed in your program.
ERROR OUT Bool When true, this output indicates that an error has occurred and the
STATUS output is valid.
STATUS OUT Word The status value of the request indicates the result of the scan or
initialization. Additional information is available in the
"USS_Extended_Error" variable for some status codes.
Typically, there is only one USS_PORT instruction per PtP communication port in the
program, and each call of this function handles a transmission to or from a single drive. All
USS functions associated with one USS network and PtP communication port must use the
same instance DB.
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