ABB AC500-S Safety User Manual page 404

Safety times
Safety function response time
n F_WD_Time2 = 30 ms
n Device_WD2 = 8 ms (output current = ~ 5 mA)
n Longest ∆T_WD = Max (0.5 * F_WD_Time1; 0.5 * F_WD_Time2) = 15 ms
With PROFINET (DX581-S ➔ SM560-S ➔ DX581-S)
SFRT = Device_WD1 + 0.5 * F_WD_Time1 + F_Host_WD + 0.5 * F_WD_Time2 + Device_WD2 + Longest
∆T_WD = 12.5 + 15 + 6 + 15 + 8 + 15 = 71.5 ms
where:
n Device_WD1 = 1 ms + 0.5 ms + 2 x 5.5 ms = 12.5 ms (no test pulses were used)
n F_WD_Time1 = 30 ms
n F_Host_WD = 3 x 2 ms (SF_WDOG_TIME_SET time) = 6 ms
F_WD_Time2 = 30 ms
n
n Device_WD2 = 8 ms (output current = ~ 5 mA)
n Longest ∆T_WD = (Max (0.5 * F_WD_Time1; 0.5 * F_WD_Time2) = 15 ms
With PROFINET (AI581-S ➔ SM560-S ➔ DX581-S)
SFRT = Device_WD1 + 0.5 * F_WD_Time1 + F_Host_WD + 0.5 * F_WD_Time2 + Device_WD2 + Longest
∆T_WD = 76.5 + 15 + 6 + 15 + 8 + 15 = 135.5 ms
where:
n Device_WD1 = 2 x 4.5 ms + 67.5 ms = 76.5 ms
n F_WD_Time1 = 30 ms
n F_Host_WD = 3 x 2 ms (SF_WDOG_TIME_SET time) = 6 ms
n F_WD_Time2 = 30 ms
Device_WD2 = 8 ms (output current = ~ 5 mA)
n
n Longest ∆T_WD = Max (0.5 * F_WD_Time1; 0.5 * F_WD_Time2) = 15 ms
DANGER!
Mistakes in SFRT calculation can lead to death or severe personal injury, especially in such applica-
tions like presses, robotic cells, etc.
NOTICE!
The high priority tasks on PM5xx Non-safety CPU ("Black channel" for safety communication) may
affect SFRT for SM560-S Safety CPU and Safety I/O modules.
404 AC500-S 30.03.2017