User Manual

Communication via AS-i - only for G110M
7.5 Cyclic and acyclic communication via CTT2
Fieldbuses
228 Function Manual, 04/2018, FW V4.7 SP10, A5E34229197B AE
Once a setpoint has been transferred completely, the setpoint present in the control will be
transferred as next setpoint. Any setpoint changes made during the transfer are not
considered.
7.5.2
Acyclic communication - standard
This type of acyclical communication supports the ID read request and the diagnostic read
request. All other requests receive the "request not implemented" message response.
● ID request:
– Master -> slave
– Slave -> master
● Diagnostic request:
– Master -> slave
– Slave -> master no error
;
Slave -> master general error
The following repsonse is issued for all other write or read requests:
● Read requests
● Write requests
7.5.3
Acyclic communication - manufacturer-specific
The manufacturer-specific acyclical communication is performed via data record 47 in PIV
format. The PIV format structure is identical with that for the USS parameter channel.
USS parameter channel (Page 116).
To reduce the transfer volume, there is not only the "normal" "data exchange" PIV
mechanism, but also the "Read data" and "Write data" commands.
● Data exchange:
– Control -> inverter request
– Inverter -> control response
● Read data:
The inverter sends a read command, and the data of the last exchange request or write
request is transferred from the inverter to the control.
● Write data
Write OK: -> 53 hex.
Because the PIV transfer protocol specifies the transfer direction independently, all
parameters can be transferred as data exchange request/response. Requests for reading
and writing data are included primarily to reduce the transferred data volume for the
repeated reading or writing of parameters.