Safety relay module SRM 21 Multi


  • Enclosure width: 22.5 mm
  • 2 NC contact combination connectable
  • Feedback circuit
  • 2 enabling paths potential-free
  • 1 auxiliary output
  • Manual or automatic start
  • LED indicator for switching condition
  • PL e, SIL CL 3

Technical data

StandardsEN ISO 13849-1, EN 62061,
EN 574, EN 60947-5-1
EnclosurePolyamid PA 6.6 V0 black;
DIN rail mounting
per EN 50022
Contact materialAgNi 10 + 0.2 µm Au
MountingDIN rail mounting
Connectionscrew connection terminals
Cable cross-sectionmin. 1x 0.5 mm² (AWG 20)
including conductor ferrules,
max. 1x 2.5 mm² (AWG 14) including conductor ferrules,
2x 1.5 mm² (AWG 16) including conductor ferrules
Degree of protectionEnclosure IP 40, Terminal block
IP 20 to IEC/EN 60529,
shock protection to VBG 4
Safety-relevant data:*
EN 60204-1stop category 0
EN 61508SIL CL 3
PFH2.2 x 10-9
PFD4.64 x 10-6
EN ISO 13849-1PL e, Category 4
TMmax. 20 years
MTTFd> 100 years
DC/DCavg> 99 %
Rated operating voltage Ue24 VDC -20 % ... +25 %
Rated operating current Ie0.125 A
Rated operating isolation voltage Ui250 VAC
Rated impulse withstand voltage Uimp4 kV
Inputs2 NC contacts, 1 feedback input,
1 start input
Outputs2 enabling paths, 1 auxiliary output
Ie/Ue enabling paths3 A/230 VAC; 5 A/24 VDC
Utilisation categoryAC-15; DC-13
Contact load capacity5 mA … 6 A; 5 V ... 250 VAC/DC
Typ. input current/
8 mA/ 24 VDC
Max. fuse ratingpower supply 2A slow blow, enabling paths 6 A gG/gN fuse
Delay on energisation/ deenergisation≤125 ms
Risk time≤ 0.5 s (switch-on delay)
Simultaneity of
input circuits
< 0.5 s with two-hand control circuit
Mechanical life> 10 million operations
Display2 LEDs for inputs, 2 LEDs for outputs,
1 LED for supply voltage, 1 LED for fault
Degree of pollution2
Overvoltage categoryIII
Ambient temperature–25 °C … +55 °C
Storage and shipping temperature–25 °C … +75 °C
Shock resistance10 g
NoteInductive loads (contactors, relays etc.) are to be suppressed by suitable circuitry.
Weight120 g
Ordering details
Type code
Type   Material no.
Safety relay module SRM 21 Multi stock type Standard versions, in stock or available at short notice 1185607
If you cannot find the version you require, just ask us! Our product portfolio to date has included many customised switchgear variants.