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Operating Instructions
Chapter
10
UE4155
8010178/TF82/2010-03-05
© SICK AG • Industrial Safety Systems • Germany • All rights reserved
57
Subject to change without notice
Technical specifications
10.2
Response time
The response time of the bus node cannot be equated with the overall response time of
the system. When considering the response time, you should instead calculate the re-
sponse time on the individual signal paths (e.g. from the field-signal connection or SDL
connection to the FPLC). The individual signals may have a different significance when
considering the safety aspects of the entire system.
The response time of the entire system depends, among other things, upon …
the response time of the devices connected to the bus node.
the device-specific transfer time (only when safe SICK-device communication is used on
the SDL connection).
the configured input delays of the safety inputs.
the processing time in the bus node.
the monitoring time for the cyclic service in the PROFIBUS.
the processing time in the FPLC.
With the aid of the following calculation schedules you can calculate the response time on
a signal path up to the hand-over of the information on the PROFIBUS output of the bus
node.
You can find information for calculating the overall response time in the documentation of
the FPLC that you are using. You can find information for calculating the (sub-)response
time of the devices connected to the bus node in the corresponding operating instructions.
Notes for users of a Siemens FPLC
If you are using a Siemens FPLC, you will require the following data for calculating the
“maximum response time” of the overall system:
Siemens term
SICK term
Description
Discrepancy time
Discrepancy time
0 ms (see chapter 3.5.2
“Monitoring the discrepancy
time” on page 20)
Max. response time if no
error occurs
Max. response time in the
event of an error
Response time
Please refer to the tables
below.
Max. acknowledgement
response time
Internal processing time
6 ms
You can calculate the response time from a field-signal input to the PROFIBUS
connection as follows:
You can calculate the response time of the device connected to the field-signal connec-
tion in accordance with the corresponding operating instructions.
Fill out the following table to determine the total response time for this signal path:
Line
Required detail
Time
1
Response time of the connected device
+ ______ ms
2
Set input delay
+ ______ ms
3
Internal processing time of the bus node
+
6 ms
4
Response time of the field-signal input
=
______
ms
Tab. 18: Data for
calculating the “maximum
response time” of the
overall system
Tab. 19: Calculate the
response time of a field-
signal input