Siemens SIMATIC S7-1200

Communication processor and Modbus TCP
13.4 Universal serial interface (USS) communication
S7-1200 Programmable controller
1158 System Manual, V4.2, 09/2016, A5E02486680-AK
Parameter type
Data type
Description
ERROR OUT Bool Error occurred: When true, ERROR indicates that an error has occurred
and the STATUS output is valid. All other outputs are set to zero on an
error. Communication errors are only reported on the USS_Port_Scan
instruction ERROR and STATUS outputs.
STATUS OUT Word STATUS indicates the result of the read request. Additional information is
available in the "USS_Extended_Error" variable for some status codes.
1
The DONE bit indicates that valid data has been read from the referenced motor drive and delivered to the CPU. It does
not indicate that the USS library is capable of immediately reading another parameter. A blank PKW request must be
sent to the motor drive and must also be acknowledged by the instruction before the parameter channel for the specific
drive becomes available for use. Immediately calling a USS_Read_Param or USS_Write_Param FC for the specified
motor drive will result in a "0x818A" error.
13.4.3.4
USS_Write_Param (Change parameters in the drive)
Note
EEPROM write operations (for the EEPROM inside a USS drive)
Do not overuse the EEPROM permanent write operation. Minimize the number of EEPROM
write op
erations to extend the EEPROM life.
Table 13- 49 USS_Write_Param instruction
LAD / FBD
SCL
Description
USS_Write_Param(REQ:=_bool_in
_,
DRIVE:=_usint_in_,
PARAM:=_uint_in_,
INDEX:=_uint_in_,
EEPROM:=_bool_in_,
VALUE:=_variant_in_,
DONE=>_bool_out_,
ERROR=>_bool_out_,
STATUS=>_word_out_,
USS_DB:=_fbtref_inout_);
The USS_Write_Param instruction modifies a parame-
ter in the drive. All USS functions associated with one
USS network and PtP communication port must use the
same data block.
USS_Write_Param must be called from a main program
cycle OB.