Predefined Master/Slave Connection Messages; Explicit Response/Request Messages - ICP DAS USA I-7242D User Manual

3.2

Predefined Master/Slave Connection Messages

The I-7242D provides "Predefined Master Slave Connection Set" device.
Users must understand these connection set to know how to operate the
device. The following section explains what the "Predefined Master Slave
Connection Set" is.
With the Predefined Master Slave Connection Set, DeviceNet allows
devices with fewer resources to take part in DeviceNet network communication.
For this reason a set of identifiers has been reserved within the Message
Group 2 to simplify the movement of I/O and configuration data typically seen
in Master/Slave relationships. The steps, which are necessary to create and
configure a connection between devices, have been removed within the
Predefined Set. The Predefined Master/Slave Connection Set allows for the
establishment of a DeviceNet communication environment using less network
and Device resources. The Predefined Connection Set contains one Explicit
Messaging Connection and allows several different I/O Connections which
include a Bit Strobe Command/Response, Poll Command/Response, Change
of State and Cyclic. The following type of messages are processed by a
DeviceNet Slave
3.2.1

Explicit Response/Request Messages

Explicit Request Messages are used to perform operations such as
reading and writing attributes. Explicit response Messages indicate the results
of the slaves answer to attempt to service an Explicit Request massage. Within
a Slave Explicit Request and Response messages are received/transmitted by
a single Connection Object. The architecture is as figure 3-3.
Figure 3-3 Architecture of Explicit message
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