Omron Sysmac NJ Series User Manual page 169

*3. Round up the calculation result in parentheses to make an integer.
The following timing chart shows an example of the timing from an execution of the SDO communi-
cations instruction to the completion of the instruction execution, based on the performance model
below.
Here, it is assumed that the program that executes the SDO communications instructions is as-
signed to the primary periodic task.
Performance Model Example
Task period of primary periodic task [ms]
Divided period [ms]
SDO response data size [byte]
Slave SDO processing time [ms]
Message response time [ms]
UPG: User program execution
EtherCAT master processing
Line delay
Slave SDO processing
NJ-series CPU Units
The calculation formula for the minimum message response time is given below.
Minimum message response time (ms) =
Task period of the task that executes the SDO communications instruction
+ (Slave SDO processing time
+ (SDO response data size/256 bytes)
*1. The slave SDO processing time depends on the slaves. Refer to relevant manuals for each slave.
*2. Round up the calculation result in parentheses to make an integer.
The following timing chart shows an example of the timing from an execution of the SDO communica-
tions instruction to the completion of the instruction execution, based on the performance model be-
low.
Here, it is assumed that the program that executes the SDO communications instructions is assigned
to the primary periodic task.
Performance Model Example
Task period of primary periodic task [ms]
SDO response data size [byte]
Slave SDO processing time [ms]
Message response time [ms]
NJ/NX-series CPU Unit Built-in EtherCAT Port User's Manual (W505)
6 Process Data Communications and SDO Communications
4
1
512
1.2
8
Task period (4 ms)
UPG
SDO communications
instruction executed.
Frame
sent.
SDO
request
received.
*1
/Task period of primary periodic task)
*2
× Task period of primary periodic task
1
512
1.2
5
Task period (4 ms)
Divided period
(1 ms)
Slave SDO
processing time
SDO response EtherCAT master captures
generation SDO response data from slave:
completed. 256 bytes per frame.
*2
x Task period of primary periodic task
Task period (4 ms)
UPG
Execution of SDO
communications
instruction
completed.
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6