Appendix D Configuring The Plc For Fisher Provox; Considerations For Configuring A Tiway I/Provox System; Plc Configuration Requirements; Network Design Considerations - Siemens SIMATIC TI500 User Manual

D.1

Considerations for Configuring a TIWAY I/PROVOX System

PLC Configuration
Requirements
Network Design
Considerations
D-2 Configuring the PLC for Fisher PROVOX
To configure the PLC to operate with the Fisher PROVOX Programmable
Controller Interface Unit (PCIU), you need to consider the following
restrictions and requirements.
A maximum of eight PLCs can be networked with each PCIU on a
PROVOX system.
A total of 64 data registers can be distributed in V-memory across one
to eight PLCs on the PCIU.
The PCIU can be configured to access up to 8 blocks of contiguous
V-memory. These blocks may encompass up to 64 words of data. The
network cannot access any data that is not defined in one of these
blocks.
Data can be read from and written to contiguous blocks of V-memory.
Words within a block of V-memory may be defined as integer or discrete
registers. The values of the discrete registers correspond to the values
of a contiguous block of 16 Y points.
For each V-memory block in a PLC that the PCIU is configured to read,
the first word in the block must be reserved as a status register. This
word does not count toward the 64-word limit.
All registers should be defined in the V-memory of the PLC. The
starting V-memory address for each PLC register block must be
configured in the PCIU.
Each PLC should have an address assigned to it ranging from 1 to 247.
These requirements have several important consequences in network and
PLC program design.
The restriction to 8 contiguous memory blocks defined for a given PCIU
means that there is a maximum of 8 PLCs that the PROVOX system can
access on a single TIWAY I network. However, if more than one contiguous
block is defined within a single PLC, then for every block after the first in
the PLC, one less PLC on the TIWAY I network can be accessed by the
PCIU. For example, if 3 V-memory blocks were defined for each PLC
connected to the PROVOX system, then a maximum of 2 PLCs could be
attached to each PCIU, with each PCIU having 2 unused memory blocks.
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