ABB AC500-S Safety User Manual page 321

● Fieldbus cycle time (PROFINET) depends on the communication settings for the
PROFINET IO device where the safety I/O module is attached to. The cycle time is a multi-
plication of two parameters of the PROFINET IO device.
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These values can be selected depending on the defined PROFINET parameters for this
PROFINET module.
● I/O bus time describes the data transfer time via I/O bus for communication between non-
safety CPU and its local I/O bus modules as well as for communication between communi-
cation interface modules and their local I/O bus modules.
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● The configurable update time for safety CPU and communication modules describes
the data transfer time via the communication module bus.
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Below, a few examples on how to calculate SFRT values under various AC500-S system config-
urations are presented. In our calculations, we use the following approach, based on
Ä [8], which allows us calculating SFRT as:
Equation 2: SFRT = Device_WD1 + 0.5 * F_WD_Time1 + F_Host_WD + 0.5 * F_WD_Time2 +
Device_WD2 + Longest ∆T_WD
2020/06/19
"Send clock" , e.g., for CI501-PNIO and CI502-PNIO: 1 ms, 2 ms or 4 ms
"Reduction ratio" , e.g., for CI501-PNIO and CI502-PNIO: 1, 2, 4, 8, 16 ... 512
AC500 V2:
The I/O bus cycle time has no fixed pre-defined cycle value. It is defined by the number
and type of the configured I/O modules independent from non-safety CPU settings. The
I/O bus time contains the following values:
- I/O bus master cycle: 2 ms (2 cycles, 1 ms each)
- I/O bus cycle time: Typically 2 ... 5 ms (2 cycles, 1 ... 2.5 ms each)
In total, the typical range for the I/O bus time is 4 ... 7 ms.
AC500 V3:
The I/O bus is driven with a defined cycle time. The I/O bus cycle time relates to non-
safety CPU setting "Bus cycle task" in tab "I/O-Bus I/O Mapping" . Refer to additional
Ä " "Bus cycle task" " on page 391.
information:
A basic definition of I/O bus cycle times is done in non-safety CPU in setting "Bus cycle
task" in tab "PLC settings" .
Example for a setting with assignment to a task with 2 ms cycle time (and lower than the
defined update time for safety CPU):
- Result for I/O bus master cycle: 2 ms = 2 cycles, 1 ms each
- Result for I/O bus cycle time: Typically 4 ... 5 ms = 2 cycles, 2 ... 2.5 ms each (if the
configured task cycle time does not fit to the I/O bus module assembly, the I/O bus cycle
time can be extended to maximum 2.5 ms)
In total, the I/O bus time is 6 ... 7 ms.
AC500 V2:
The update time can be configured within the range of 0 ... 20000 ms for both safety
CPU and communication modules.
AC500 V3:
The update time for safety CPU can be configured within the range of 1 ... 20000 ms.
The update time for communication modules is valid for, e.g., PROFINET IO controller
(CM579-PNIO) and PROFINET IO device (CM589-PNIO). The update time relates to
the communication module setting "Bus cycle task" in tab "PROFINET-IO-Controller I/O
Mapping" . Refer to additional information:
PROFINET IO controller.
A basic definition of cycle times in the non-safety CPU is done in "PLC Settings" - "Bus
cycle task" .
DANGER!
Input delay, input delay accuracy and test pulse low phase are not needed for
AI581-S. However, the worst case fixed internal input delay of 67.5 ms shall be
used for AI581-S instead.
3ADR025091M0208, 12, en_US
Safety function response time
Ä " "Bus cycle task" " on page 391, e.g., for
Safety times
Ä [3] and
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