Accessing From The User Program - Omron CJ1W-DRM21 Operation Manual

3 Data Exchange with the CPU Unit
Device Variable for CJ-series Unit
Device variables for CJ-series Units are variables for which AT is specified for the I/O port explained
below. The user program uses device variables for CJ-series Unit to access the Configuration Unit
such as DeviceNet Unit.
For allocation of the device variables for CJ-series Unit to the I/O port, refer to How to Create Device
Variables for CJ-series Unit (P. 3-5).
I/O Port
An "I/O port" is a logical interface for data exchange by a CPU Unit with a DeviceNet Unit or other
Configuration Unit.
An I/O port has a unique pre-defined name for each unit model and function.
An I/O port is automatically created by preparing the Unit Configuration with Sysmac Studio.
For details on the I/O ports defined for DeviceNet Unit, refer to 3-2 Device Variables for CJ-series
Unit (Software Switches, Statuses) and 3-3 Device Variables for CJ-series Unit (Allocations Setting
Table, Slave Detailed Status).
DeviceNet Unit has two types of I/O ports; one is for the following software switch/status data, and
the other is for allocations setting table/slave detailed status data.
Software switches / Status data
Software switches (execution instructions of each function from the CPU Unit to the DeviceNet Unit),
DeviceNet Unit statuses and error data are allocated.
Allocations Setting Table, Slave Detailed Status Data
Allocations Setup Tables that the user can freely set and individual slave statuses by node address
are allocated.
User-defined Variable
Slaves are allocated to the memory used for CJ-series Unit when you use the functions shown
below.
• Master remote I/O communications (fixed/user-set allocation)
• Slave remote I/O communications (fixed/user-set allocation)
To use this area from the user program, you need to create a user-defined variable of AT specifica-
tion.
3-1-2

Accessing From the User Program

From the user program, various types of information are exchanged using AT specified device variables
for CJ-series Unit that are allocated to the I/O ports, and AT specified user-defined variables that are
allocated to slave allocation areas.
From the user program, the following is used to exchange various types of information:
3-4 CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)