Process Data Exchange In Program Mode; A-3-1 Detection Method And Timing Considerations; Detection Method And Timing Considerations - Omron CJ1W-ECT21 Operation Manual

Appendices
A-3 Process Data Exchange in PROGRAM
Mode
When an EtherCAT master or NJ-series CPU Unit with a mounted EtherCAT Slave Unit enters PRO-
GRAM mode, the EtherCAT Slave Unit will continue to exchange process data over the EtherCAT net-
work. However, this process data is not updated in the CPU Unit that is in PROGRAM mode and is no
longer accurate. The EtherCAT Slave Unit will maintain its current state and will not automatically indi-
cate this condition. It is necessary to monitor this condition with the user program to determine if the
exchanged process data remains accurate.
A-3-1

Detection Method and Timing Considerations

This section describes the following items.
• The method for detecting transition of the EtherCAT master and the CPU Unit to PROGRAM mode
• Consideration of detection timing
Detection Method
The suggested method to detect that an EtherCAT master and a CPU Unit enter PROGRAM mode
requires the user program that toggles process data bits ON and OFF between the EtherCAT master
and an NJ-series CPU Unit with a mounted EtherCAT Slave Unit. If the process data bits stop toggling,
the user program is no longer executing which is an indication that the EtherCAT master and the CPU
Unit are in PROGRAM mode.
Refer to the manuals for the EtherCAT master and the NJ-series CPU Unit's user's manual for more
information on creating the user program.
Timing Considerations
When implementing these detection methods, it is important to consider the maximum I/O response
time of the EtherCAT Slave Unit. Both program examples include a timer instruction to detect that pro-
cess data is not changing within a fixed amount of time. This time should be adjusted to a value that is
more than the maximum I/O response time. Refer to 4-6-1 I/O Response Time on page 4-10 for details
on the maximum I/O response time.
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CJ-series EtherCAT Slave Units Operation Manual for NJ-series CPU Unit (W542)