VIPA System 200V IM Series, Manual

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Chapter 4 Interbus
Manual VIPA System 200V
4-14 HB97E - IM - Rev. 06/29
Consistent data is the term used for data that belongs together by virtue of
its contents. This is the high and the low byte of an analog value (word
consistency) as well as the control and status byte along with the
respective parameter word for access to the registers.
The data consistency for a station is guaranteed by the Interbus data com-
munication protocol. Synchronous scanning guarantees the consistency of
the entire process image. Inconsistencies can arise due to asynchronous
accesses to the data areas of the Interbus master from the control CPU.
You can find information on secure access methods to the master interface
in the respective manuals.
The basic data consistency is only guaranteed for 1Byte. This means that
the bits belonging to a single byte were read or written as a single unit. This
byte-related consistency suffices when digital signals are being processed.
However, when the data length exceeds a byte, for instance for analog
values, then the data consistency must be expanded. You must ensure that
you transfer consistent data properly from the Interbus master into your
PLC.
For further information please refer to the manual for your Interbus master.
You may combine a maximum of 16 input and 16 output modules with an
Interbus coupler. The maximum data width for the input and output data is
10 words.
The configuration of the bus coupler or peripheral modules via the Interbus
PCP protocol is not supported.
When the bus coupler is being initialized addresses are assigned to the
System 200V peripheral module that are used by the bus coupler to
communicate with the module under normal operating conditions. It is not
possible to remove or insert any module while the system is active. This is
due to the fact that addresses are only assigned after a POWER-ON or a
RESET and since the data width of Interbus modules must not change
while the system is operational.
In accordance with RS422 standards any remote bus segment (= distance
between any two stations) may be at distances up to 400m. The maximum
total extent of the system is 12.8km.
Note!
Before the change is implemented, the respective bus coupler must be
powered off. Please ensure that you change the initialization in the master
in accordance with the changes to the periphery!
Data consistency
Restrictions