VIPA IM 253 DP Series, Manual, Page: 47 / 100

Manual VIPA System 200V Chapter 3 Deployment IM 253DP
HB97E - IM - RE_253-xDPxx - Rev. 12/44 3-7
The key feature of version DP-V1 is the extended function for acyclic data
communication. This forms the requirement for parameterization and
calibration of the field devices over the bus during runtime and for the
introduction of confirmed alarm messages.
Transmission of acyclic data is executed parallel to cycle data
communication, but with lower priority.
DPM 1
Master Class 1 DPM 2
Master Class 2
Token
DP-Slave 1 DP-Slave 2 DP-Slave 3
Slave 3
Cycle:
Cyclic Access
of DPM 1 Acyclic Access
of DPM 2
Slave 1 Slave 2 Slave 3
The DPM 1 (Master Class 1) has the token and is able to send messages
to or retrieve them from slave 1, then slave 2, etc. in a fixed sequence until
it reaches the last slave of the current list (MS0 channel); it then passes on
the token to the DPM 2 (Master Class 2). This master can then use the
remaining available time ("gap") of the programmed cycle to set up an
acyclic connection to
any slave (e.g. slave 3) to exchange records (MS2
channel); at the end of the current cycle time it returns the token to the
DPM1.
The acyclic exchange of records can last for several scan cycles on their
"gaps"; at the end, the DPM 2 uses the gap to clear the connection.
Similarly as well as the DPM 2, the DPM 1 can also execute acyclic data
exchange with slaves (MS1 channel).
Function
Acyclic data
communication
(DP-V1)