M72 - Mezzanine Card with Motion Counter

The M72 M-Module is a timer, counter and comparator with four 32-bit counter units. The four counters work independently in several modes, e.g. counting decoder signals or measuring frequencies. Each counter can be loaded with a preset value and can generate several events. Events can set or reset output signals, which are optically isolated.

The mezzanine card M72 can also be used to generate timed signals. In addition it features line-break detection. The sensor signals are optically isolated and can be used as TTL, RS422 or 24 V inputs.

The M72 is based on the M-Module ANSI mezzanine standard. It can be used as an I/O extension in any type of bus system, i.e. CPCI, VME or on any type of stand-alone SBC. Appropriate M-Module carrier cards in 3U, 6U and other formats are available from MEN or other manufacturers.


  • 4 independent cascadable 32-bit counters
  • 2 comparators per counter
  • Quadrature incremental encoder interface
  • Pulse width/frequency measurement
  • Multimode event generation
  • Customized counter modes via FPGA
  • RS422 or TTL or 24V
  • Optical isolation
  • -40 °C to +85 °C versions


Four Independent Counters
  • 32-bit up/down counter
  • Two 32-bit comparators
  • One 32-bit preload register
  • Clock frequency 40MHz
Counter Modes
  • Single count
  • 1x quadrature, 2x quadrature, 4x quadrature
  • Frequency measurement
  • Pulse width "high", pulse width "low"
  • Period measurement, timer
  • 3 inputs for each counter
  • RS422, TTL or 24V input
  • Timing characteristics for the different modes:
    • Single count: t high > 200ns; t low > 200ns
    • Quadrature: time between two active edges (t edges > 400ns)
    • Frequency measurement: gating time 10ms, < 2.5MHz
    • Pulse width: t high or t low > 15µs
    • Period: t high or t low > 15µs, internal frequency 2.5MHz
    • Synchronization of input signals with onboard clock (40MHz)
  • Input debouncing time: 100ns
  • RS422 input characteristics: see user manual
  • TTL input characteristics:
    • Uin < 0.5V = "low"
    • Uin > 2.2V = "high"
    • Uin max. = 12V
    • Max. input current: ±5mA
  • 24V input characteristics:
    • Uin < 1V = "low"
    • Uin > 10V = "high"
    • Uin max. = 30V
    • Max. input current: ±10mA
    • Max. frequency measurement: 500kHz
  • 4 TTL outputs (optically isolated)
  • Output current:
    • High current: 10mA
    • Low current: 15mA
Peripheral Connections
Via front panel on a shielded 44-pin HD-Sub receptacle connector
M-Module Characteristics
Electrical Specifications
  • Isolation voltage: 500V DC
  • Supply voltage/power consumption: +5V (4.85V..5.25V), 550mA
  • MTBF: 70,000h @ 50°C (derived from MIL-HDBK-217F)
Mechanical Specifications
  • Dimensions: conforming to M-Module Standard
  • Weight: 100g
Environmental Specifications
  • Temperature range (operation):
    • 0..+60°C
    • Industrial temperature range on request
    • Airflow: min. 10m³/h
  • Temperature range (storage): -40..+85°C
  • Relative humidity (operation): max. 95% non-condensing
  • Relative humidity (storage): max. 95% non-condensing
  • Altitude: -300m to + 3,000m
  • Shock: 15g/11ms
  • Bump: 10g/16ms
  • Vibration (sinusoidal): 2g/10..150Hz
  • Conformal coating on request
PCB manufactured with a flammability rating of 94V-0 by UL recognized manufacturers
Tested according to EN 55022 (radio disturbance), IEC 61000-4-2 (ESD) and IEC 61000-4-4 (burst)
Software Support