DANGER!
The input delay accuracy has to be calculated based on the following assumptions:
–
Not used for safety analog inputs;
–
If no test pulses are configured for the given digital safety input, then input delay accuracy can be
calculated as 1 % of set input delay value (however, input delay accuracy value must be at least
0.5 ms!)
–
If test pulses are configured for the given digital safety input, then depending on the type of the
module (DI581-S or DX581-S) and set input delay value, the following input delay accuracy values
can be used in SFRT calculations:
The following terms are defined in Fig. 126 and Fig. 127:
n
Device_WD1 is an internal input device watchdog time in ms which includes:
–
Input delay (variable as parameter; not used for safety analog inputs which have an internal input
delay of 67.5 ms in the worst case);
–
Input delay accuracy (see tables below)
–
Test pulse low phase (fixed to 1 ms and optional (only if test pulses are used); not used for safety
analog inputs);
–
Two times internal cycle time (fixed; AI581-S
➔
4.5 ms, DX581-S
➔
5.5 ms and DI581-S
➔
6.5 ms);
n
F_WD_Time1 is the first watchdog time in ms for receipt of the new valid telegram (variable as parameter
and depends on system configuration);
n
F_Host_WD is the watchdog time in ms equal to three times of the set value using
SF_WDOG_TIME_SET POU (variable as parameter through SF_WDOG_TIME_SET POU and depends
on the number of F-Devices, safety application program and system configuration);
n
F_WD_Time2 is the second watchdog time in ms for receipt of the new valid telegram (variable as
parameter and depends on system configuration).
n
Device_WD2 is an internal output device watchdog time in ms which includes:
–
Internal safety output device cycle time (fixed; DX581-S
➔
5.5 ms);
–
Output processing time (fixed to 1.5 ms);
–
Hardware delay (current dependent, e.g., ~1 ms (747 µs at 5 mA) and the maximum of 4 ms under
the maximum output current of 500 mA). If precise values are needed, please contact ABB technical
support.
Table 88: DI581-S safety module
Input delay (ms)
Input delay accuracy (ms)
1
2
2
2
5
3
10
4
15
5
30
6
50
7
100
10
Safety times
Safety function response time
30.03.2017
AC500-S
397
