Electro-Numerics, Inc.
42213 Sarah Way, Temecula, CA 92590, USA


Tel: 800-854-8530 (USA)
Tel: 951-699-2437 
Fax: 951-695-7246


    Micro Series Stopwatch Meters
Resolution down to 0.2 s for timing of fast, one-time events


  • Available in three digit heights: 0.56" for panel mounting, 1.0" (Mighty-1) or 5.0" (Mighty-5) for long-distance viewing.
  • Times single events from 1 s to 999,999 hrs
  • Selectable display of single event time or accumulated time of all events.
  • 6-digit red or green LED display.
  • Selectable H, M or S decimal format.
  • Selectable HH.MM.SS clock format.
  • Inputs from NPN or PNP proximity switches, contact closures, digital logic, magnetic pickups down to 12 mV, or AC inputs up to 250 Vac.
  • Triggers on positive or negative pulse edges.
  • Isolated 5, 10 or 24 Vdc excitation output to power sensors.
  • Choice of isolated plug-in options for control and computer interface:
    dual relays, 4-20 mA & 0-10 V analog output, RS232/485 serial I/O, low voltage AC & DC power.
  • 1/8 DIN case environmentally sealed to NEMA-4X from front panel.
  • 1/8 DIN version certified to UL 3101-1, CAN/CSA-C22.2, EN 61010-1 (CE Mark).


Signal I/O board for Micro stopwatch meterStopwatch Mode

The Micro stopwatch meter can time single events from 1 s to 999,999 hrs, with a resolution down to 0.2 s for fast events. It can time processes which produce start and stop pulses, or time the width of a single pulse. The display is updated continuously during timing of slow events.

  • A-A Stopwatch Mode. Time can be measured between a start pulse and a stop pulse, both on Channel A, from either the positive or negative edges.

  • A-B Stopwatch Mode. Time can also be measured between a start pulse on Channel A (positive or negative edge) and a stop pulse on Channel B (positive or negative edge). This mode allows inputs from different sources. In addition, the A and B inputs can be tied together to start the stopwatch with one polarity and stop it with the other polarity.

Timing is achieved by counting 5.5 MHz clock pulses. Micro stopwatch timers use the FR dual-channel signal conditioner and Extended counter main board.


The event time (Item #1) may be displayed H, M or S format with six-digit resolution. The longest single-event timing interval is 999,999 hours. The highest resolution is 1 s. The event time may also be displayed in HH.MM.SS clock format with 1 s resolution. 

The stopwatch display is updated during timing at a rate controlled by a gate time, up to 25/s. It is reset to zero when the next start pulse occurs. Accumulated time from multiple events (Item #2) is also tracked and may be displayed up to 999,999 hours.

Universal Signal Conditioner

The dual-channel signal conditioner used for pulse detection accepts inputs from proximity switches with PNP or NPN output, TTL or CMOS logic, magnetic pickups, contact closures, and other signals from 12 mV to 250 Vac. Jumper selections provide optimum operation for different sensor types and noise conditions.

A built-in isolated 5, 10, or 24 Vdc excitation supply can power proximity switches and other sensors, and eliminate the need for an external power supply.

Built-in Flexibility

Plug-in isolated analog output, dual setpoint controller, and RS232/485 serial communications boards can upgrade Micro and Mighty Series stopwatch meters from a stand-alone display to system interface and control. The ability of the instruments to output an isolated 4-20 mA signal which tracks time may be unique among stopwatches.

Micro Series meters can be powered from 95-240 Vac 10% and 95-370 Vdc, or optionally from 12-34 Vac and 10-48 Vdc. Any setup functions and front panel keys may be locked out for simplified usage and security. The popular 1/8 DIN version with 0.56" high digits is environmentally sealed to NEMA-4X (IP65) from the front when panel mounted, and is available with red or green LEDs. All power and signal connections are via plug-in screw-clamp connectors.


Digit Height
6 digits, 7-segment
Available with 0.56", 1.0", 4.0" or 5.0" digits.

High brightness red. Green available with 0.56" digits.
-999999 to +999999
Four LED lamps
Selectable Hysteresis
Rolloff Filter
Debounce Time

AC, pulses from NPN, PNP transistors, contact closures, magnetic pickups.
Common ground for channels A & B
-12 mV to +12 mV, +30 mV to +60 mV, -30 mV to -20 mV,
-150 mV to +150 mV, +350 mV to +600 mV, -600 mV to -350 mV,
-1.15 V to +1.15 V, +1.25 V to +2.1 V, -2.1 V to -1.25 V
Selectable: 1 MHz, 30 kHz,  250 Hz
Selectable: 0, 3, 50 ms

Stopwatch Mode

Timing Modes:
    With CH A only
    With CH A tied to CH B
    With CH A and CH B
Timing Interval
Timing Resolution
Selectable Decimal Time
Selectable Clock Time
Output & Display Update
Gate Time

+ to + edge, or - to - edge.
+ to - edge, or - to + edge.
+ edge of A to + edge of B, + edge of A to - edge of B,
- edge to A to - edge of B, - edge of A to - edge of B
1 s to 999,999 hrs
1 s to 1 hr
999999 H, M or S format with decimal point
HH.MM.SS format
Gate time + 30 ms 
Programmable from 10 ms to 199.99 s

Time Base
Span Tempco
Long-term Drift

Crystal calibrated to 2 ppm
1 ppm/C (typ)
5 ppm/year

Voltage, std.
Voltage, opt.
Power isolation
95-240 Vac 10% and 95-370 Vdc
12-34 Vac and 10-48 Vdc
DC or 49-440 Hz
Safety-rated to 250 Vac, meter ground to earth ground,
DC to 60 Hz, 4.2 kVp per High Voltage Test
Excitation Output
5 Vdc
10 Vdc
24 Vdc
Output isolation
5 Vdc 5%, 100 mA max
10 Vdc 5%, 120 mA max
24 Vdc 5%, 50 mA max
50 Vdc to meter ground
Operating Temperature
Storage Temp.
Relative Humidity
0C to 60C
-40C to 85C
95% at 40C, non-condensing
NEMA-4X (IP-65) when panel mounted
Electrical Connections
Pinout of Micro digital stopwatch meter


Stopwatch Mode

Stopwatch mode of Micro digital stopwatch

The stopwatch mode is used to time single events between start and stop pulses on the same channel. Duration of a single wave shape can be measured by tying the A and B channels together.

Timing Process Dynamics

Timing process dynamics by Micro digital stopwatch

The start and stop pulses used for timing can be generated by the dual relay board in a Micro analog panel meter or digital counter. For example, the start and stop pulse edges can be created as temperature passes two alarm setpoints, or temperature cycles in a hysteresis control mode.

 Replacing an Oscilloscope with a Micro Stopwatch Meter

Replacing an oscilloscope by a Micro digital stopwatch

An oscilloscope is great for viewing and timing pulses in a lab. However, in fixed installations where digital timing accuracy and control outputs are required, a low-cost Micro time stopwatch or interval meter will be the instrument of choice. Resolution to 0.2 s is feasible.

 Instrumenting a Pulsed Laser System

The diagram below illustrates some of the many possibilities in instrumenting a pulsed laser system with Micro dual-channel counters: elapsed time, number of pulses, pulse width, pulse separation, duty cycle, and pulse rep rate.

Instrumenting a laser system using Micro timers and stopwatches

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Electro-Numerics, Inc., 42213 Sarah Way, Temecula, CA 92590, USA
Tel: 800-854-8530 (USA), 951-699-2437;  Fax: 951-695-7246;  sales@electronumerics.com