Response time in a host-guest group
If t
he host switches an OSSD pair based on the monitoring results of a guest device, the
transmission time in the host-guest group and the processing time in the host must be
taken into account in addition to the response time of the guest device.
You can calculate the response time using the following formula:
t
R
= (t
S
+ t
I
) × n + t
OG
+ t
T
+ t
IH
+ t
OH
Where:
•
t
R
= response time
•
t
S
= scan cycle time of the guest device
°
Setting “30 ms”: t
S
= 30 ms
°
Setting “40 ms”: t
S
= 40 ms
°
Setting “50 ms”: t
S
= 50 ms
•
t
I
= time for interference protection of the guest device
°
Mode 1 (default): t
I
= 0 ms
°
Mode 2: t
I
= 1 ms
°
Mode 3: t
I
= 2 ms
°
Mode 4: t
I
= 3 ms
•
n = set multiple sampling of the guest device
Preset to n = 2.
Multiple sampling can be changed for the safety laser scanner or for each individ‐
ual f
ield (2 ≤ n ≤ 16).
•
t
OG
= 35 ms (t
ime for processing and output of the guest device)
•
t
T
= transmission time in the host-guest group (see Safety Designer, window
Connection overview, column Response time via network [ms]:)
•
t
IH
= 28 ms (time for input of the host)
•
t
OH
= time for processing and output of the host
Dependent on output used:
°
OSSD pair 1: t
OH
= 10 ms
°
OSSD pair 2, 3, 4: t
OH
= 20 ms
Further topics
•
"C
onnection overview", page 109
13.5 Course of the OSSD test over time
The safety laser scanner tests the OSSDs at regular intervals. To do this, the safety
la
ser scanner switches each active OSSD briefly (for max. 300 μs) to the OFF state and
checks whether this channel is voltage-free during this time.
Make sure that the machine’s control does not react to these test pulses and the
machine does not switch off.
OSSD 1.A
V
t
OSSD 1.B
V
t
t
S
t
S
t
S
t
S
t
S
t
S
t
S
t
S
t
S
Figure 95: Switch-off tests
13 TECHNICAL DATA
188
O P E R A T I N G I N S T R U C T I O N S | microScan3 Pro I/O 8025424/1ELL/2022-01-21 | SICK
Subject to change without notice
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