Leading Manufacturer of Safety Interlock Switches and Machine Guard Safety Switch Devices for Automation and Process Safety

Viper Safety Relay with Added Diagnostics (SCR-21-i)

The SCR-21-i internal logic uses force guided relays to achieve cross monitoring, ensuring single faults are detected at or before the next demand upon the safety function.

  • Outputs 2NC contacts and 1NO contact
  • Dual Channel Safety Inputs
  • Up to PLe, SIL 3, Category 4
  • LED Indication for Reset Circuit Status

Part NumberPart DescriptionInputsOutputsAuxiliarySupplyTerminals
280001SCR-21-i Screw Terminals2-Channel Wiring2 N/C1 N/O24VdcScrew
280001-PSCR-21-i Pluggable Terminals2-Channel Wiring2 N/C1 N/O24VdcPluggable

Power Supply Circuit
Rated operating voltage24V AC/DC
Operating voltage tolerance-15% - +10%
Rated supply frequency50Hz – 60Hz
Rated supply current75mA
Power consumption24V AC/ DC 2.5W

Control Circuits
Rated output voltageS11 24V DC
Input currentS11..S14 100mA
Response time100ms
Release time25ms
Recovery timeApprox. 1s

Output Circuits
Rated output voltage250VAC
Max. current per output6A
Max. total current all outputs6A
Safety contact breaking CapacityAC 230V, 4A for AC-15 / DC 24V, 30W, 2A, DC-13
Minimum contact load10V 10mA
Min. contact fuses4A Slow blow, 6A Fast blow
Contact materialAgSnO2
Contact service life10 x 10 6

General Data
Rated impulse withstand voltage4kV
Rated insulation voltage250V
Temperature range-20C + 55C
Degree of contamination2
Overvoltage categoryIII
MountingAny position