Write_Pm - Siemens SIMATIC S7-200 System Manual

WRITE_PM

L
A
WRITE_PM
D
EN
F
XMT_REQ
B
D
DRIVE
PARM
VAL
DB_PTR
CALL WRITE_PM,
S
T XMT_REQ,
L DRIVE, PARM,
VAL, DB_PTR,
DONE, ERR
221 222 224
PARM is the parameter number. VAL is the parameter value to be written.
The address of a 16-byte buffer must be supplied to the DB_PTR input. This buffer
is used by the WRITE_PM instruction to store the results of the command issued
to the MicroMaster Drive.
When the WRITE_PM instruction completes, the DONE output is turned on and
the ERR output byte contains the result of executing the instruction. Table 11-6 on
page 11-16 defines the possible error conditions that may result from executing the
instruction.
Note
Only one READ_PM or WRITE_PM instruction can be active at a time.
S7-200 Programmable Controller System Manual
A5E00066097-02
Using USS Protocol Instructions to Communicate with Drives
The WRITE_PM instruction writes a drive parameter to a
specified location. The WRITE_PM transaction
completes when the MicroMaster Drive acknowledges
receipt of the command, or when an error condition is
DONE
posted. The logic scan continues to execute while this
ERR
process awaits a response.
The EN bit must be on to enable transmission of a
request, and should remain on until the DONE bit is set
signaling completion of the process. A WRITE_PM
request is transmitted to the MicroMaster drive on each
scan when XMT_REQ input is on. Therefore the
XMT_REQ input should be pulsed on through an edge
detection element which causes one request to be
transmitted for each positive transition of the EN input.
The DRIVE input is the address of the MicroMaster Drive
226 to which the WRITE_PM command is to be sent. Valid
addresses of individual drives are 0 to 31.
11-13