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3 Data Exchange with the CPU Unit
3-2
CJ-series User Defined CAN Unit Operation Manual for NJ-series CPU Unit (W517)
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.
The CPU Units and CJ-series User Defined CAN Units exchange data as shown in the table and chart
below.
Data exchange type
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.
3-1-1
Data Flow
Access methods from
the user program
AT specification
destination
Data exchange timing
Unit data type
Device variable for
CJ-series Unit
I/O port
During I/O refresh
Communication Enable
Status
Number of Delayed Send Mes-
sages
Number of Delayed Receive
Messages
User-defined variable
Memory used for
CJ-series Unit
During I/O refresh
•
Send Buffers
•
Send Triggers
•
Receive Buffers
•
Receive Triggers
At I/O refresh after instruc-
tion execution
•
Direct Transmit of 11-bit ID
CAN Message
•
Direct Transmit of 29-bit ID
CAN Message
Unit Cyclic Refresh
Summary of Contents for CJ1W-CORT21
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Page 140: ...Appendices A 6 CJ series User Defined CAN Unit Operation Manual for NJ series CPU Unit W517...
Page 141: ...Index 1 CJ series User Defined CAN Unit Operation Manual for NJ series CPU Unit W517 I Index...
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