Safety relays - PSR-MS21-1NO-1DO-24DC-SC

Safety relay for failsafe controllers up to SILCL 3, Cat. 4, PL e, 1-channel operation, automatic start, 1 enabling current path, US = 24 V DC according to IEC 61131-6, fixed screw terminal block


Product Details

Product type Safety relays
Application Controllers
Relay type Electromechanical relay with force-guided contacts in accordance with IEC/EN 61810-3
Insulation characteristics
Overvoltage category III
Typical response time < 150 ms (automatic start)
Typ. starting time with Us < 250 ms (when controlled via A1)
Typical release time < 20 ms (when controlled via A1)
Restart time < 1 s
Recovery time < 500 ms

Maximum power dissipation for nominal condition 3.1 W (at US = 30 V, IL² = 36 A²)
Nominal operating mode 100% operating factor
Rated control circuit supply voltage US 19.2 V DC ... 30 V DC
Rated control circuit supply voltage US 24 V DC -20 % / +25 % (at A1)
Rated control supply current IS typ. 35 mA
Power consumption at US typ. 840 mW
Inrush current 150 mA (Δt = 25 ms at Us)
Filter time 2.5 ms (at A1 in the event of voltage dips at Us)
max. 3 ms (at A1; test pulse width; blanking pulses/dark test)
1 s (at A1; test pulse rate; blanking pulses/dark test)
Where test pulse width ≤ 1 ms: test pulse rate = 5 x test pulse width
max. 1 ms (at A1; test pulse width; switch-on pulses/light test)
100 ms (at A1; test pulse rate; switch-on pulses/light test)
Unless switch-on pulses/light tests are safety-related, they should be disabled.
Protective circuit Surge protection; Suppressor diode
Protection against polarity reversal for rated control circuit supply voltage
Rated insulation voltage 250 V AC
Rated insulation voltage 250 V AC
Rated surge voltage/insulation Safe isolation, reinforced insulation 6 kV between input circuit and enabling current path (13/14)
Basic insulation 4 kV between all current paths and housing

Inrush current < 10 mA (with Us/Ix to S35)
Max. permissible overall conductor resistance 150 Ω
Voltage at input/start and feedback circuit 24 V DC -20 % / +25 %
Current consumption < 2 mA (with Us/Ix to S35)

Relay: Enabling current path
Output description safety-related N/O contacts
Number of outputs 1 (undelayed)
Contact type 1 enabling current path
Contact material AgSnO2
Switching voltage min. 12 V AC/DC
max. 250 V AC/DC (Observe the load curve)
Switching capacity min. 60 mW
Inrush current min. 3 mA
max. 6 A
Limiting continuous current 6 A (observe derating)
Sq. Total current 36 A2 (observe derating)
Switching frequency max. 0.5 Hz
Mechanical service life 10x 106 cycles
Output fuse 6 A gL/gG (N/O contact)
4 A gL/gG (for low-demand applications)
Output description non-safety-related
Number of outputs 1 (digital, PNP)
Voltage typ. 21 V DC (Voltage at terminal block “24V” - 3 V)
Current max. 100 mA
Maximum inrush current 500 mA (Δt = 1 ms at Us)
Short-circuit protection Yes

Connection technology
pluggable no
Conductor connection
Connection method Screw connection
Conductor cross section solid 0.2 mm² ... 2.5 mm²
Conductor cross-section AWG 24 ... 12
Screw thread M3

Status display 2 x green LEDs
Operating voltage display 1 x green LED

Width 6.8 mm
Height 93.1 mm
Depth 102.5 mm

Housing material PBT
Housing color yellow

Safety data
Stop category 0
Safety data: EN ISO 13849
Category 4
Performance level (PL) e (4 A DC13; 5 A AC15; 8760 switching cycles/year)
Safety data: IEC 61508 - High demand
Equipment type Type A
Safety Integrity Level (SIL) 3 (4 A DC13; 5 A AC15; 8760 switching cycles/year)
Probability of a hazardous failure per hour (PFHD) 1.00 x 10-9 (4 A DC13; 5 A AC15; 8760 switching cycles/year)
Proof test interval 240 Months
Duration of use 240 Months
Safety data: IEC 61508 - Low demand
Equipment type Type A
Safety Integrity Level (SIL) 3
Probability of a hazardous failure on demand (PFDAVG) 1.96 x 10-4
Proof test interval 52 Months

Ambient conditions
Degree of protection IP20
Min. degree of protection of inst. location IP54
Ambient temperature (operation) -40 °C ... 60 °C (observe derating)
Ambient temperature (storage/transport) -40 °C ... 85 °C
Maximum altitude ≤ 2000 m (Above sea level)
Max. permissible humidity (storage/transport) 75 % (on average, 85% infrequently, non-condensing)
Max. permissible relative humidity (operation) 75 % (on average, 85% infrequently, non-condensing)
Shock 15g
Vibration (operation) 10 Hz ... 150 Hz, 2g

Certificate CE-compliant

Air clearances and creepage distances between the power circuits
Standards/regulations DIN EN 50178

Mounting type DIN rail mounting
Assembly instructions See derating curve
Mounting position vertical or horizontal

Item number 2702192
Packing unit 1 pc
Minimum order quantity 1 pc
Sales Key C18
Product Key DNA171
Catalog Page Page 219 (C-6-2019)
GTIN 4055626010199
Weight per Piece (including packing) 83.4 g
Weight per Piece (excluding packing) 69 g
Customs tariff number 85371098
Country of origin DE


ECLASS-9.0 27371819
ECLASS-10.0.1 27371819
ECLASS-11.0 27371819


ETIM 8.0 EC001449


UNSPSC 21.0 39122200

UL Listed

Approval ID: FILE E 140324

cUL Listed

Approval ID: FILE E 140324

Functional Safety

Approval ID: 44-205-15124301

Functional Safety

Approval ID: 44-780-15124301

cULus Listed

REACh SVHC Lead 7439-92-1
China RoHS Environmentally Friendly Use Period = 50 years
For information on hazardous substances, refer to the manufacturer’s declaration available under “Downloads”

Compatible Products

Your advantages

Up to Cat. 4/PL e in accordance with EN ISO 13849-1, SIL 3 in accordance with IEC 62061
Low housing width of just 6.8 mm
1-channel control
1 enabling current path, 1 digital signal output
Couples digital output signals from failsafe controllers to I/O devices (valves, etc.) for electrical isolation and power adaptation
Automatic activation