Switching Performance And Service Life Of Contacts - Siemens SIMATIC S7 Functional Safety Manual

Technical specifications
A.3 Fail-Safe signal module (SM) technical specifications
Adjacent relay contacts in the same channel of the SM 1226 F DQ 2 x Relay are not rated
to separate AC line from SELV / PELV.
Death or serious personal injury and damage to machines and equipment may result if
SELV/PELV circuits are wired adjacent to high voltage circuits on this module.
The A and B circuits of each output must either be both AC line or both SELV.
A.3.4.5

Switching performance and service life of contacts

Note the "Switching performance and service life of contacts" table below. You should equip
Inductive loads with suppression circuits to avoid shortened relay contact life and to avoid
excessive switching noise. Refer to "Guidelines for inductive loads" (Page 101) for more
information:
Table A- 63 Switching performance and service life of contacts
Resistive load
For resistive load
For inductive load to IEC
60947-5-1 DC13/AC15
188
WARNING
Voltage
24 VDC
230 VAC
24 VDC
230 VAC
Current
5.0 A
3.0 A
2.0 A
1.0 A
0.5 A
5.0 A
3.0 A
2.0 A
1.0 A
0.5 A
1.0 A
0.5 A
1.0 A
0.5 A
Duty cycle (typical) Normally-
Open (NO) contact
0.35 million
0.5 million
0.75 million
1.8 million
4 million
0.1 million
0.15 million
0.2 million
0.4 million
0.8 million
0.1 million
0.2 million
0.2 million
0.35 million
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA