Omron CJ1W-DRM21, CS1W-DRM21 operation manual Overview of DeviceNet, Section

Overview of DeviceNet Section 1-1

1-1 Overview of DeviceNet

DeviceNet functions

DeviceNet is a multi-bit, multi-vendor network that combines controls and data on a machine/line-control level and that conforms to DeviceNet open field net- work specifications.

Three types of communications are supported: 1) Remote I/O master commu- nications that automatically transfer I/O between slaves and the CPU Unit to which a DeviceNet Unit is mounted without any special programming in the CPU Unit, 2) Remote I/O slave communications that automatically transfer I/O between the Master and the CPU Unit to which a DeviceNet Unit is mounted, and 3) Message communications that read/write messages, control operation, or perform other functions for other CPU Units to which a DeviceNet Unit is mounted and slaves. Message communications are achieved by executing specific instructions (SEND (192), RECV (193), and CMND (194)) from the program in the CPU Unit to which the DeviceNet Unit is mounted.

Fixed allocations

Remote I/O master communications

User-set allocations

Fixed allocations

Remote I/O slave communications

User-set allocations

Explicit message communications

Message communications

FINS message communications

The following functions are supported with a CS/CJ-series DeviceNet Unit.

1,2,3... 1. Without the Configurator Software Tool

a)I/O area words can be flexibly allocated for remote I/O Master and Slave communications. Three types of fixed allocations as well as user-set allocations through allocated DM Area words are possible.

b)More than one DeviceNet Unit can be mounted under a single PC.

c)More than one DeviceNet Unit can be connected in a single network. With the Configurator, remote I/O can be allocated in any order, i.e., not necessarily in the other of node addresses.

Note The Configurator that is connected through a dedicated Board or Card uses one node in the DeviceNet network. It does not use a node if it is connected by a serial line.

2.A CS/CJ-series DeviceNet Unit can function as either a master or slave in remote I/O communications. Both can be used simultaneously.

3.With a CS/CJ-series DeviceNet Unit, the DeviceNet network can be treat- ed exactly like a Controller Link, Ethernet, or other network for message communications or remote programming and monitoring by a CX-Pro- grammer.

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