MM-122A High Precision Miniature Weld Checker

The MM-122A is the very latest in stand-alone weld checker technology. This full function, cost effective unit is designed to monitor every type of welding control. The unit’s “miniature” design allows it to be mounted in any position on the welding machine. Limits for Peak or RMS current provide vital weld quality indicators. Multiple schedules, error signaling and versatile I/O make this unit as valuable for bench systems as it is for automated welding systems. Printer options or RS-232/485 provide for data collection and weld process analysis, critical in today’s advanced manufacturing processes.

The MM-122A uses a Toroidal coil for sensing. The correct coil needs to be matched to your application.


  • Measures Single Phase AC, DC Inverter, AC Inverter, Capacitor Discharge, Transistor, Single-phase Rectified, 3-phase Rectified, 3-phase Low Frequency
  • Small Size allows for flexible mounting
  • Current Range: 0.010 – 199.9kA
  • RMS or PEAK Values
  • Conduction angle
  • Measures time in milliseconds or cycles
  • Upper and lower limits
  • 31 Weld Schedules
  • “No weld current” Detection
  • Error signaling
  • Data communication via RS-232/485
  • Printer Connection with Standard Reports
  • Analog output for waveforms
  • Weld Counter
  • Measures stepped weld sequences
  • Good/No-Good, Hi/Low machine outputs


Sample MM-122A Printout (using the optional printer)

Millisecond Readings
Schedule Information
Error Only Printouts or all Summary Data
High/Low Indications


Miyachi MM-122A Weld Tester Specifications

  • Power Supply: Single Phase 100 – 240 VAC ±10% 50/60 Hz or 24 VDC ±10%
  • Current Sensor: Toroidal coil (pick the correct coil for your application)
  • Current Range
    • 0.010-0.199kA (X10 coil)
    • 0.100-1.999kA
    • 1.00-19.99A
    • 10.0-199.9kA
  • Monitored Value: RMS or PEAK
  • Time Range
    • 0.5 to 500.0 cycles (AC and DC), 1-2000 mS (AC and DC)
    • 0.50-25.00 mS (transistor)
    • 0.50 9.99 mS / 05.0-99.9 mS (capacitor) Tp, Th
  • Conduction Time: 30 degrees through 180 degrees
  • Data Output: RS-232 / 485 or printer
  • Number of Schedules: 31
  • Dimensions (H x W x D): 2.8″ x 9.7″ x 7.5″ (70mm x 246mm x 190mm)
  • Weight: 4.2 lbs (1.9 kg)

For further information, please contact T. J. Snow. We will be glad to help you select the weld checker for your needs and budget.

Optional Accessories: Toroidal Coils

This Item Replaces

  • MM-121B
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