Allen-Bradley 1756-CNB/E, User Manual

Page: 37 / 186

Publication 1756-UM523F-EN-P - December 2006
Design the System 37
Do the redundant chassis use more than 1 ControlNet
network?
•
Yes — See page 29.
•
No — Skip this guideline.
The NUT of each network must be within the values indicated on page 29. If
you use a larger network update time (NUT), the controller could lose its
connection with a module during a switchover. This could cause outputs to
change state.
Example
Guideline Details
If the NUT of this network is 5 ms…
ControlNet
Network 1
Then the NUT of this network must be
21 ms or less.
ControlNet
Network 2
If the smallest
NUT on a network
is (ms) Then the largest NUT on any other
network must be less than or equal
to (ms)
2 15
3 17
4 19
5 21
6 23
7 25
8 27
9 29
10 31
11 33
12 35
13 37
14 39
15 41
16 43
17 46
18 48
19 50
20 52
21 55
22 57
23 59
24 62
25 64
26 66
27 68
28 71
29 73
30 75
31 78
32 80
33 82
34 84
35 87
36 89
37...90 90
If the smallest
NUT on a network
is (ms) Then the largest NUT on any other
network must be less than or equal
to (ms)