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

Viper Safety Relay with Time Delay (SCR-31-42TD-i)

The SCR-31-42TD-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.


  • Delayed Outputs: 4NC and 2NO (0-30 secs)
  • Standard Outputs: 3NC 1NO
  • Dual Channel Safety Inputs
  • Up to PLe, SIL 3, Category 4

Part NumberDescriptionInputsOutputsAuxiliarySupplyTerminals
280006-CSCR-31-42TD-i Screw Terminals with 0-30sec delay2-Channel Wiring3 N/C Instant / 4 N/C Delayed1 N/O Instant / 1 N/O Delayed24VdcScrew
280006-PSCR-31-42TD-i Pluggable Terminals with 0-30sec delay2-Channel Wiring3 N/C Instant / 4 N/C Delayed1 N/O Instant / 1 N/O Delayed24VdcPluggable
280009SCR-31-42TD-i Screw Terminals with 0-30sec delay2-Channel Wiring3 N/C Instant / 4 N/C Delayed1 N/O Instant / 1 N/O Delayed24VdcScrew

Power Supply Circuit
Operating voltage24V AC/DC
Operating voltage tolerance-15% - +10%
Rated supply frequency50Hz – 60Hz
Rated supply current190mA
Power consumption24V AC/DC 5W

Control Circuits
Rated output voltageS11 24V DC
Input currentS11.S14 100mA
Response time100ms
Release time25ms
Recovery timeApprox. 1s
Time delay range0 – 30s

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 (Creepage and Clearance: Outputs -> Control Circuits: 5.5mm)
Rated insulation voltage250V
Degree of protection IP20
Temperature range2
Overvoltage category III
Weight0.3kg
Mounting Any position
Time delay range0 – 30 Seconds