3 Safety-Related Functions 11.03
3.12 SI I/Os using fail-safe modules connected to PROFIBUS DP (840D from SW 6.3.30)
© Siemens AG 2003 All Rights Reserved
3-196 SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
3.12.8 Response times
The response time considered here is the time between a signal changing at
the input of an F/DI module and the signal changing at the relevant output of an
F/DO module.
The NC response time T
R_NCK
is approximated to:
T
PST
> T
IPO:
T
R_NCK
= T
INPUT
+ T
OUTPUT
+ 2* T
DPM
+ 1*T
IPO
+ 3* T
PST
T
PST
= T
IPO:
T
R_NCK
= T
INPUT
+ T
OUTPUT
+ 2* T
DPM
+ 2*T
IPO
Note
The NC response time is decisive when disabling (1 > 0) an output.
The PLC response time T
R_PLC
is approximated to:
T
R_PLC
= T
INPUT
+ T
OUTPUT
+ 4 ms + 1* T
PST
+ 2* T
OB1
Note
The PLC response time is decisive when activating (0 > 1) an output.
where:
T
INPUT
: Processing/transfer times for F-DI module and DP slave
T
OUTPUT
: Processing/transfer times for F-DO module and DP slave
T
DPM
:
Internal transfer cycle of DP master, typically 2 ms
T
IPO
: Parameterized IPO cycle
T
PST
: Parameterized PROFIsafe cycle
T
OB1
: OB1 processing time
3.12.9 Functional limitations
I/O modules available for SINUMERIK 840D:
- F modules
-
DMP modules
- Onboard I/O
can be operated in parallel.
Multiple assignment of inputs of the various modules to the same SPL SGE are
detected and displayed in an alarm:
• Alarm: 27204 "PROFIsafe: Dual allocation MD Number [Index] -
MD
Number [Index]"
It is not possible to directly connect the I/Os (F useful data) of an F module to
axial NCK SGE/ SGAs. They can only be connected in the context of the NCK-
SPL which must be installed for the purpose.
NC response time
PLC response time
Mixed mode for
I/O modules
Axial NCK-SGE/SGA
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