M400 – Active Wheel Speed Generator


  • 6 independent galvanically isolated frequency outputs 
  • Support of conventional wheelspeed sensors as well as wheelspeed sensors with serial data protocol, e.g. Continental OH42x and OH44x
  • Possibility to simulate missing teeth 
  • Configurable jitter for each individual tooth 
  • Support of the currents needed by the ECU, no external adaptation circuits necessary 
  • Usable as current source and current sink 
  • Possible currents: +/-7, 14, 21mA and 28 mA 
  • Accuracy and range of values: 40 bits 
  • Jitter (peak to peak): 7.5ns 
  • Galvanic isolation for each channel to each other and to system supply 
  • 2 different frequency update modes:
    - Immediate frequency adaptation 
    - Synchronized frequency adaptation
  • 3 different pulse width modes:
    - Pulse-duty factor 
    - Fixed high level duration 
    - Fixed low level duration

Technical Data

Number of output channels



+/-7mA, 14mA, 21mA, 28mA

Rated voltage range
  • 6V <= (WSH - WSL) <= 22V 
  • Inverse-polarity protected
Frequency range

 0 ...1MHz

Supported sensor types
  • Conventional active wheel speed sensors (7mA /14mA) 
  • Sensor with serial protocol, based on Continental OH42x10 
  • Sensor with serial protocol, based on VDA specification (e.g. Continental OH44x)
Serial protocol

Up to 15 free configurable data bits

Baud rate of serial protocol

Configurable in a range of 10 .. 240us

Number of teeth per turn

Up to 255 teeth per turn, configurable

Missing teeth

Up to 255 missing teeth per wheel turn, configurable

Jitter of teeth

Each tooth can be shifted in between a range of “-” half the gap between 2 teeth and “+” half the gap between 2 teeth

Output current

Better than +/-3%

Frequency resolution
  • <520kHz: 0.00024Hz

  • >=520kHz: 0.01552Hz

Pulse width resolution
  • Pulse-duty factor mode: better than 2x10-10 

  • Fixed pulse width mode: 1 digit=7.5ns

Jitter (peak to peak)



25 Pin SubD connector, female

Address space

A08D16 or A24D32

  • Emulating 6 active wheel speed sensors ESC test systems 
  • Providing conventional sensor signals or serial protocol data 
  • Testing fail-safe mechanisms by simulation of missing teeth

  • M404 For emulation of passive wheel speed sensors