Safety Loop; Safety Values - ABB AC500-S Safety User Manual

Overview of AC500-S Safety PLC

Safety values

2.3 Safety loop

The safety loop, to which the AC500-S Safety PLC belongs, consists of the following three parts: sensors,
Safety PLC and actuators.
~35 % of safety loop PFH
Fig. 3: Typical safety loop with AC500-S Safety PLC
For the calculation of the PFH/PFD values of an examplary safety system, a maximum of 15 % is assumed
for the Safety PLC. The detailed values of PFH for AC500-S Safety modules and PFH/PFD of the Safety
PLC Loop can be obtained on request.
2.4 Safety values
Table 1: The following safety values can be used for AC500-S safety modules:
Type Description
SM560-S (-XC) Safety module
AI581-S (-XC) Safety Analog Input
Module
DI581-S (-XC) Safety Digital Input
Module
DX581-S (-XC) * Safety Digital Input/
Output Module
(1) - according to IEC 62061 and IEC 61508 ed. 2 (continuous and high demand mode)
(2)
- according to ISO 13849-1
(3)
- Diagnostic Coverage (see ISO 13849-1)
(4)
- Probability of dangerous failure per hour according to IEC 61508 ed. 2 (Continuous and high demand
mode) and IEC 62061
(5) - Mean Time To Failure (years) dangerous according to ISO 13849-1
(6)
- Proof Test Interval - Mission Time - Lifetime Years
* - See the danger note below
20
Safety Input
Sensor
Module
~1 5 % of safety loop PFH
Safety loop
Safety PLC
Safety Output
Safety CPU
Module
Module
SIL (1) PL (2) DC (3)
3 e ≥ 95 %
3 e ≥ 95 %
3 e ≥ 95 %
3 e ≥ 94 %
AC500-S
Actuator
~50 % of safety loop PFH
PFHd (4) MTTFd
< 3.0E-09 > 100 years 20
< 3.0E-09 > 100 years 20
< 3.0E-09 > 100 years 20
< 3.0E-09 > 100 years 20
(5) T1 (6)
30.03.2017