Omron DeviceNet Safety, System Configuration Manual

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33
Calculating and Verifying the Reaction Time Section 2-3
Example 2: Local Input – Remote Output
Maximum reaction time (ms)
= Switch reaction time
+ NE1A-series Controller-A local input/remote output reaction time
+ Network reaction time
+ NE1A-series Controller-B remote input/local output reaction time
+ Actuator reaction time
= Switch reaction time
+ ON/OFF delay (NE1A-series Controller) + 6 + 6
×
2
+ 28
+
7 + 2.5
+ Actuator reaction time
= 55.5 + ON/OFF delay + Switch reaction time + Actuator reaction time
2-3-3 Verifying the Maximum Reaction Time
Check that the calculated maximum reaction time meets the required specifi-
cations in all safety chains. If the reaction time exceeds the required specifica-
tions, re-examine the network design, taking into consideration the following
points for the maximum reaction time to meet the requirement specifications:
•
Shortening the EPI will shorten the network reaction time. Shortening the
EPI, however, narrows the network bandwidth that can be used for other
connections.
•
The NE1A-series Controller cycle time is automatically calculated based
on the program size, the number of connections, etc. It is also possible to
use different NE1A-series Controller Controllers for safety chains that
require a high-speed reaction time and other safety chains.
DeviceNet
NE1A-SCPU01
A
Switch
Safety connection (EPI = 7 ms)
network reaction time = 28 ms
NE1A-series Controller cycle time = 6 ms
I/O refresh cycle
time = 6 ms
NE1A-SCPU01
B
Actuator
NE1A-series Controller cycle time = 7 ms
I/O refresh cycle
time = 3.5 ms