Installation guide

66 Estimating Network Performance
890 USE 100 00
3.5 Communication Paths and Queueing
With multiple devices processing messages asynchronously on the
network, it becomes possible for an individual device to have several
concurrent transactions in process. The peer processor in each device
maintains multiple communication paths of various types. It opens a
path when a transaction begins, keeps it open during the transaction,
and closes it when the transaction terminates. When the path is
closed, it becomes available to another transaction.
Both the originating and destination devices open paths and maintain
them until the transaction completes. If the transaction passes
through Bridge Plus devices to access a destination on another
network, each bridge opens and maintains a path at each of its two
network ports. Thus a logical path is maintained between the
originating and destination devices until the transaction is finished.
3.5.1 Path Types
Each Modbus Plus device has the following types of paths:
V Data Master Path for data reads and writes and for get and clear
remote statistics, originated in the device
V Data Slave Path for data reads and writes as they are received in
the device
V Program Master Path for programming commands originated in the
device
V Program Slave Path for programming commands as they are
received in the device.
Each path is independent of the others. Activity in one path does not
affect the performance of the other paths.