PMS request: WRITE
(Original Document)
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At a Glance
This request is used to write variables to a device connected to the INTERBUS bus.
This request is carried out using the WRITE_VAR communication function.
Syntax
The syntax of the communication function is presented in the following format:
WRITE_VAR(ADDR('r.m.0.pcp'), 'PMS', index, subindex, %MWi:L, %MWk:4)
The following table describes the various parameters of the function.
Parameter
Description
ADDR('r.m.0.pcp')
Address of the destination entity of the exchange:
  • r.m: rack, module
  • 0 : channel (always 0)
  • pcp: pcp channel number
'PMS'
Type of PMS object (always PMS in upper case)
index
Double word or value identifying the object to be accessed
subindex
Word or value specifying the object to be accessed
%MWi:L
Word table containing the data destined for the PCP device (minimum length = 1)
%MWk:4
Exchange management parameters: four words identifying the address of the Control Expert data used to control the WRITE_VAR function.
Management parameters
The following table gives details of %MWk:4 words:
Word number
Most significant byte
Least significant byte
Data managed by
%MWk
Exchange number
Activity bit
system
%MWk+1
Operation report
Communication report
%MWk+2
Timeout: value complies with the per-user bandwidth of INTERBUS messages
you
%MWk+3
Length: number of bytes of the response stored in the buffer parameter. The length must be initialized in order to activate the function.
For more information about %MWk+1, refer to Operation and Communication reports.
Example of use
The example shows the writing of the setpoint speed (1000 rpm) for an Altivar 66.
The data to be sent is coded in 2 bytes (1 word, %MW90).
The send length is initialized at a value of 2 bytes.