NORD Drivesystems BU0230 - Manual (Page 72)

Functional safety with NORD SK 200E frequency inverters
72 BU 0230 GB-2712
10.5 Data for the safe pulse block
(only for SK 210E, SK 215E, SK 230E and SK 235E)
Function Specification
Input voltage +24 V
Voltage tolerance ±25 % (18 V…30 V)
Operation at OSSD - 20 % +25 % (19.2 V…30 V)
Power consumption
(mean value)
≤ 125 mA for SK 2xxE in Size 1 to 3
≤ 40 mA for SK 2x0E in Size 4
Peak current
(peak, when switching on or at the
OSSD)
≤ 500 mA for SK 2xxE in Size 1 to 3
≤ 250 mA for SK 2x0E in Size 4
Cable length ≤ 100 m (refer to EMC, grouping)
Line capacitance ≤ 20 nF per connected inverter
Switch-on delay ≤ 200 ms
Reaction time ≤ 300 ms (≤ 65 ms typical)
Cycle time ≥ 1 s
Requirements made of OSSDs Test pulse width ≤ 500 µs
Duty (high level) ≥ 90 %
Distance between double pulses ≥1ms (note the duty factor)
Safety integrity level (IEC 61508) SIL3
Probability of a hazardous failure per
hour PFH = 0 for SK 2xxE in Size 1 to 3
PFH = 0.0058 FIT = 5.8*10
-12
/h for SK 2xxE in Size 4
Probability of a hazardous failure on
call-up PFD = 0 for SK 2xxE in Size 1 to 3
PFD = 5.23*10
-5
for SK 2xxE in Size 4
Proportion of safe failures SFF = 100 % for SK 2xxE in Size 1 to 3
SFF = 99 % for SK 2xxE in Size 4
Safety category
(as per to EN ISO 13849-1)
Cat. 4
Performance level
(as per to EN 13849-1) PL e
The mean time until a hazardous
failure MTTF
d
= "High" (>100 years)
Diagnostic coverage level DC cannot be determined (PFH=0) for SK 2xxE in Size 1 to 3
DC > 99 % for SK 2xxE in Size 4
Lifetime TM = 20 years