SIRIUS safety relay Basic unit Advanced series with time delay 0.05-3 s Relay enabling circuits 2 NO instantaneous 2 NO delayed Us = 24 V DC screw terminal
Product Type: Industrial Automation Component
General
| Article number |
3SK1121-1CB41 |
| product brand name |
SIRIUS |
| product category |
Safety relays |
| product designation |
safety relays |
| design of the product |
Relay enabling circuits |
| product type designation |
3SK1 |
| product line |
Advanced basic unit |
Product Function
| product function parameterizable |
sensor floating / sensor non-floating, monitored start-up / automatic start, 1-channel / 2-channel sensor connection, cross-circuit detection, startup testing, antivalent sensors, 2-hand switches, time delay |
product function
| ● automatic start |
Yes |
| ● light barrier monitoring |
Yes |
| ● protective door monitoring |
Yes |
| ● magnetically operated switch monitoring NC-NO |
Yes |
| ● magnetically operated switch monitoring NC-NC |
Yes |
| ● laser scanner monitoring |
Yes |
| ● light array monitoring |
Yes |
| ● EMERGENCY OFF function |
Yes |
| ● monitored start-up |
Yes |
| ● pressure-sensitive mat monitoring |
No |
| product feature cross-circuit-proof |
Yes |
| suitability for interaction press control |
Yes |
| suitability for operation device connector 3ZY12 |
Yes |
suitability for use
| ● monitoring of floating sensors |
Yes |
| ● monitoring of non-floating sensors |
Yes |
| ● position switch monitoring |
Yes |
| ● EMERGENCY-OFF circuit monitoring |
Yes |
| ● opto-electronic protection device monitoring |
Yes |
| ● magnetically operated switch monitoring |
Yes |
| ● safety-related circuits |
Yes |
General technical data
| certificate of suitability UL approval |
Yes |
| product feature protective coating on printed-circuit board |
No |
| power loss [W] maximum |
2.5 W |
| insulation voltage rated value |
300 V |
| degree of pollution |
3 |
| overvoltage category |
3 |
| surge voltage resistance rated value |
4 000 V |
| protection class IP of the enclosure |
IP20 |
| shock resistance |
10 g / 11 ms |
| vibration resistance according to IEC 60068-2-6 |
5 ... 500 Hz: 0.75 mm |
| operating frequency maximum |
360 1/h |
| reference code according to IEC 81346-2 |
F |
| Substance Prohibitance (day/month/year) |
11/05/2012 |
| SVHC substance name |
Lead CAS-No. 7439-92-1
Lead monoxide (lead oxide) CAS-No. 1317-36-8
2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one CAS-No. 71868-10-5
Melamine CAS-No. 108-78-1
6,6'-di-tert-butyl-2,2'-methylenedi-p-cresol CAS-No. 119-47-1
4,4'-isopropylidenediphenol (Bisphenol A, BPA) CAS-No. 80-05-7 |
| Net Weight |
0.272 kg |
Ambient conditions
| installation altitude at height above sea level maximum |
4 000 m |
| ● note |
Derating, see Product Notification 109792701 |
ambient temperature
| ● during operation |
-25 ... +60 °C |
| ● during storage |
-40 ... +80 °C |
| relative humidity during operation |
10 ... 95 % |
| air pressure according to SN 31205 |
900 ... 1 060 hPa |
Electromagnetic compatibility
| installation environment regarding EMC |
This product is suitable for Class A environments only. In household environments, this device can cause unwanted radio interference. The user is required to implement appropriate measures in this case. |
| EMC emitted interference |
IEC 60947-5-1, Class A |
Safety related data
| product function suitable for safety function |
Yes |
| safe state |
Safety outputs switched off |
| test wear-related service life necessary |
Yes |
| function test interval maximum |
1 a |
| diagnostics test interval by internal test function maximum |
600 s |
| stop category according to IEC 60204-1 |
0 / 1 |
IEC 62061
| SIL Claim Limit (subsystem) according to EN 62061 |
3 |
Safety Integrity Level (SIL)
| ● according to IEC 62061 |
SIL 3 |
| ● at single-channel evaluation according to IEC 62061 |
1 |
| ● at 2-channel evaluation according to IEC 62061 |
3 |
| PFHD with high demand rate according to IEC 62061 |
0,0000000037 |
| ● according to IEC 61508 |
3 |
| ● for delayed release circuit according to IEC 61508 |
SIL3 |
| ● at single-channel evaluation according to IEC 61508 |
1 |
| ● at 2-channel evaluation according to IEC 61508 |
3 |
| safety device type according to IEC 61508-2 |
Type B |
| PFHD with high demand rate according to IEC 61508 |
0,0000000037 |
| PFDavg with low demand rate according to IEC 61508 |
0.000007 |
| Safe failure fraction (SFF) |
99 % |
ISO 13849
| category according to EN ISO 13849-1 |
4 |
performance level (PL)
| ● according to ISO 13849-1 |
PL e |
| ● at single-channel evaluation according to ISO 13849-1 |
c |
| ● at 2-channel evaluation according to ISO 13849-1 |
e |
| ● for delayed release circuit according to ISO 13849-1 |
e |
category
| ● according to ISO 13849-1 |
4 |
| ● at 2-channel evaluation according to ISO 13849-1 |
4 |
| overdimensioning according to ISO 13849-2 necessary |
No |
hardware fault tolerance
| ● according to IEC 61508 |
1 |
| ● at single-channel evaluation according to IEC 61508 |
0 |
| ● at 2-channel evaluation according to IEC 61508 |
1 |
T1 value
| ● of service life according to IEC 61508 |
20 a |
| ● for proof test interval or service life according to IEC 61508 |
20 a |
Electrical Safety
| touch protection against electrical shock |
finger-safe |
design of the fuse link
| ● for short-circuit protection of the NO contacts of the relay outputs required |
gL/gG: 6A or circuit breaker type A: 3A or circuit breaker type B: 2A or circuit breaker type C: 1A |
design of input
| ● cascading input/functional switching |
Yes |
| ● feedback input |
Yes |
| ● start input |
Yes |
| pulse duration of the sensor input minimum |
75 ms |
| number of sensor inputs 1-channel or 2-channel |
1 |
● as NC contact
| — for signaling function instantaneous contact |
0 |
● as NO contact
| — safety-related instantaneous contact |
2 |
| — safety-related delayed switching |
2 |
| mechanical service life (operating cycles) typical |
10 000 000 |
| thermal current of the switching element with contacts maximum |
5 A |
switching capacity current of the NO contacts of the relay outputs at DC-13
| ● at 24 V |
3 A |
| ● at 115 V |
0.2 A |
| ● at 230 V |
0.1 A |
switching capacity current of the NO contacts of the relay outputs at AC-15
| ● at 115 V |
3 A |
| ● at 230 V |
3 A |
| total current maximum |
12 A |
| operational current at 17 V minimum |
5 mA |
make time with automatic start
make time with automatic start after power failure
| ● typical |
6 500 ms |
| ● maximum |
6 500 ms |
make time with monitored start
| ● maximum |
110 ms |
| backslide delay time after opening of the safety circuits typical |
40 ms |
backslide delay time in the event of power failure
| ● typical |
30 ms |
| ● maximum |
40 ms |
| adjustable OFF-delay time after opening of the safety circuits |
0.05 ... 3 s |
| recovery time after opening of the safety circuits typical |
30 ms |
| recovery time after power failure typical |
6.5 s |
pulse duration
| ● of the ON pushbutton input minimum |
0.15 s |
Control circuit/ Control
| type of voltage of the control supply voltage |
DC |
| control supply voltage at DC rated value |
24 V |
operating range factor control supply voltage rated value of magnet coil at DC
| ● initial value |
0.8 |
| ● full-scale value |
1.2 |
Installation/ mounting/ dimensions
| mounting position |
any |
| fastening method |
screw and snap-on mounting |
| height |
100 mm |
| width |
22.5 mm |
| depth |
121.5 mm |
required spacing
| ● for grounded parts at the side |
5 mm |
Connections/ Terminals
| type of electrical connection |
screw terminal |
wire length
| ● with Cu 1.5 mm² and 150 nF/km per sensor circuit maximum |
4 000 m |
type of connectable conductor cross-sections
| ● solid |
1x (0.5 ... 2.5 mm²), 2x (1.0 ... 1.5 mm²) |
| ● finely stranded with core end processing |
1x (0.5 ... 2.5 mm²), 2x (0.5 ... 1.0 mm²) |
| ● for AWG cables solid |
1x (20 ... 14), 2x (18 ... 16) |
| ● for AWG cables stranded |
1x (20 ... 16), 2x (20 ... 16) |
| type of electrical connection plug-in socket |
No |
Environment
| Environmental Confirmations |
Yes |
| EPD Typ II/III (with life cylce assessment) |
Yes |
General Product Approval
| CCC |
Yes |
| cULus |
Yes |
| EAC |
Yes |
| EU declaration of conformity |
Yes |
| UK Declaration of Conformity |
Yes |
| KC |
Yes |
| RCM |
Yes |
Functional Saftey
| Type Examination Certificate |
Yes |
Test Certificates
| Type Test Certificates/Test Report |
Yes |
Maritime application
| DNV (Det Norske Veritas) |
Yes |
| LR (Lloyds Register) |
Yes |
| RINA (Registro Italiano Navale) |
Yes |
| RMRS (Russian Maritime Register) |
Yes |
other
| Confirmation |
Yes |
| Chinese Quality Checkmark |
Yes |
Railway
Image database (product images, 2D dimension drawings, 3D models, device circuit diagrams, EPLAN macros, ...)
https://www.automation.siemens.com/bilddb/cax_de.aspx?mlfb=3SK1121-1CB41&lang=en
| last modified: |
7/26/2026 |
| Date8/1/2026 |
Subject to change without notice© Copyright Siemens 2026 |
Applications
This Industrial Automation Component is designed for industrial automation applications, offering reliable performance and compatibility with Siemens automation systems. Suitable for manufacturing, process control, and building automation environments.
