Figure 13: Tolerance band of the contour as reference field (protective field within the protected
openin
g, edge of the protected opening = reference contour)
1
Tolerance band of the reference contour field
2
Distance of the protective field from the reference contour, to ensure availability
4.3.4 Monitoring case switching time
Overview
If y
ou switch between monitoring cases, you must specify the time at which the switch‐
over takes place.
When determining the time, you must consider the following points, among others:
•
At the time of switchover, one person can already be in the newly activated
protective field. The new protective field must therefore be active in good time so
that the device detects a person in the newly activated protective field before a
hazard arises there.
•
In some cases, the process of switching between monitoring cases takes so long
that the new monitoring case is not available inside the response time provided.
This means that it may not be possible to detect a person in the protective field in
time. In cases like this, you must start switching between monitoring cases earlier.
The following parameters influence the duration of the process:
°
Set input delay
°
Processing time for the chosen input
•
In addition to the parameters considered below, the switching signal’s time-of-
flight up to the device must also be taken into account. Depending on the commu‐
nication protocol, these include the network cycle time and the processing time of
a controller, for example.
Approach
1.
Calculate how long it takes to switch between monitoring cases:
t
CSR
= t
ID
+ t
I
where:
°
t
C
SR
= time required for switching between monitoring cases in milliseconds
(ms)
°
t
ID
= input delay for the control inputs in milliseconds (ms)
(Only when using an assembly that emulates local inputs.)
4 P
ROJECT PLANNING
24
O P E R A T I N G I N S T R U C T I O N S | nanoScan3 – EtherNet/IP™ 8027909/2023-02-22 | SICK
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