Data Flow; Data Exchange With The Cpu Unit - Omron CJ1W-CORT21 Operation Manual

3 Data Exchange with the CPU Unit

3-1 Data Exchange with the CPU Unit
Data exchange between this Unit and the CPU Units uses the I/O port and memory for CJ-series Unit
allocated to the User Defined CAN Unit.
3-1-1

Data Flow

The CPU Units and CJ-series User Defined CAN Units exchange data as shown in the table and chart
below.
Data exchange type
Access methods from
the user program
Device variable for
CJ-series Unit
User-defined variable
Unit Cyclic Refresh
The User Defined CAN Unit performs a cyclic refresh for five memory areas of the CPU. In one of these
memory areas, control and status flags are present and the state information is included in these flags.
During a Unit Cyclic refresh, data is transferred between the CPU and the Unit. The Unit determines
independently when to cyclically refresh its data. This data is not processed immediately after the Unit
Cyclically refreshes. Several CPU Cyclic refreshes may occur between two Unit Cyclic refreshes. This
means that rising/falling edges and/or data changes must be handled with care.
3-2
AT specification
Data exchange timing
destination
I/O port During I/O refresh
Memory used for During I/O refresh
CJ-series Unit
At I/O refresh after instruc-
tion execution
CJ-series User Defined CAN Unit Operation Manual for NJ-series CPU Unit (W517)
Unit data type
Communication Enable
Status
Number of Delayed Send Mes-
sages
Number of Delayed Receive
Messages
• Send Buffers
• Send Triggers
• Receive Buffers
• Receive Triggers
• Direct Transmit of 11-bit ID
CAN Message
• Direct Transmit of 29-bit ID
CAN Message