Woodward DSS-2 Digital Speed Switch

    Versatile speed monitoring or equipment protection device


    Woodward’s DSS-2 combines the convenience of manual adjustments with the flexibility of a computer-based calibration tool. The two-channel electronic speed switch executes a variety of speed-related functions, including starter motor disable and engine overspeed protection. DSS-2 monitors engine rpm via a magnetic pickup (MPU) input and controls two independent relays. Once engine speed exceeds the user-selected speed setpoint, the relay will go to the designated set condition.

    DSS-2 has two multi-turn potentiometers for manual speed setpoint adjustment. A computer interface is provided for additional adjustments with the All-purpose Calibration Tool (ACT). For most applications, DSS-2 can be connected and adjusted with simple hand tools. For more advanced features, the calibration tool provides user-friendly access. Three indicator lamps permit system monitoring and diagnosis without use of additional tools.

    The unit is fully potted for harsh environments and comes with Euro-style connectors for easy installation. The DSS-2’s universal input accommodates both 12-volt and 24-volt systems. And, it is reverse-polarity protected to prevent damage in case of incorrect wiring.  

    Put DSS-2 to the test in your most rugged speed switch applications.

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    • Digital technology for accuracy and reliability
    • Versatility of a speed monitoring or equipment protection device
    • Flexibility of either manual or PC-calibrated adjustments
    • Easy attachment via Euro-style terminal
    • Power input 9-30 Vdc
    • CE marked
    • Reverse polarity protection


    As an electronic speed switch for internal combustion engines, DSS-2 performs in these typical engine applications:

    • Crank motor disconnect above normal cranking speeds
    • Engine overspeed protection
    • Engine underspeed protection
    • Engine load control (e.g. wood chipper--stop feed when engine lugs below a set speed, enable feed when engine speed recovers

    As an equipment protection device, DSS-2 demonstrates its versatility in several functions:
    • PTO protection
    • Magnetic brake retarder
    • Shift inhibitor
    • Bus door control 

    DSS-2 can also function as the following:
    • Autocrank controller
    • Glow plug controller


    Power Input 

    9-30 Vdc, reverse polarity protected

    Operating Current:
                                  Both Channels On:

    Both Channels Off: 


    12 V: 100 mA / 24 V: 100 mA

    12 V: 50 mA / 24 V: 50 mA

    Relay Contact Ratings @ 28 Vdc 

    Resistive Load: 1 to 10A

    Inductive Load: 1 to 8A




    Operating Temperature 

    -40°F to +185°F  (-40°C to 85°C)


    4 G’s from 40 to 2000 Hz


    10 G’s @ 45 Hz


    UV, chemical resistant. UL 94 V-O flame retardant. Encapsulated for reliability in harsh environments


    Euro-style terminal block


    Manual or with PC-based All-purpose Calibration Tool / ACT  [SA-5206]


    0.38 lbs (0.17 kg)