Siemens SIMATIC S7 System Manual page 185

Parameter
REQ
DRIVE
PARAM
INDEX
EEPROM
VALUE
USS_DB
DONE
ERROR
STATUS
S7-1200 Programmable controller
System Manual, 11/2009, A5E02486680-02
Parameter Data type
type
IN Bool
IN USInt
IN UInt
IN UInt
IN Bool
IN Word, Int,
UInt,
DWord,
DInt, UDInt,
Real
IN Variant
OUT Bool
OUT Bool
OUT UInt
Description
Send request: When true, it indicates that a new write
request is desired. This is ignored if the request for this
parameter is already pending.
Drive address: This input is the address of the USS drive.
The valid range is drive 1 to drive 16.
Parameter number: This input designates which drive
parameter is written. The range of this parameter is 0 to
2047. See your drive manual for details on how to access
any parameters above this range.
Parameter index: This input designates which Drive
Parameter index is to be written. A 16-bit value where the
Least Significant Byte is the actual index value with a range
of (0 to 255). The Most Significant Byte may also be used
by the drive and is drive specific. See your drive manual for
details.
Store To Drive EEPROM: When true, writes to the drive
parameter will be stored in the drive EEPROM. If false, the
write is temporary and will not be retained if drive is power
cycled.
The value of the parameter that is to be written. It must be
valid on the transition of REQ.
This is a reference to the instance DB that is created and
initialized when a USS_DRV instruction is placed in your
program.
Done: When TRUE indicates that the input VALUE has
been written to the drive.
This bit is set when USS_DRV sees the write response data
from the drive.
This bit is reset when either:
You request the drive's confirmation that the write is
complete via another USS_WPM poll or on the second of
the next two calls to USS_DRV.
Error occurred: When true, this 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 instruction ERROR and
STATUS outputs.
This is the status value of the request. It indicates the result
of the write request. Additional information is available in
the "USS_Extended_Error" variable for some status codes.
Programming instructions
6.3 Global library instructions
185