Weld checker (desk-top type): MM-370C.MM-122A.WM-A728

"Visually" control for better weld quality.
Model : MM-370C MM-122A WM-A728

[ MM-370C ]
Possible to measure current, voltage, welding time, weld force, and displacement value.

  • USB memory device connectable
    Measured data and waveform data can be saved in a USB memory device.
  • Bidirectional communication
    Connected MM-370C with a PC, data can be both write and read.
  • Polarity selectable
    Displacement value can be read in both + (plus) indication and – (minus) indication.

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  • Supports various types of welders.

    Supports single-phase AC welders, DC inverter welders, AC inverter welders, and transistor type welders.

  • Simple operation with a dial

    Turn the dial to scroll the screen, move the cursor, and select items. Press the dial to select the item where the cursor is located.

  • Clear display of the current and voltage

    320x240 dots/4.7-inch color LCD screen.

  • Various display capability

    Displays various welding waveforms without using an oscilloscope.

  • Waveform re-display feature (FIT feature)

    The displayed waveform can be shifted and zoomed in and out in the screen. Even if the waveform of where you would like to observe went off the screen, it can be back to display the waveform again. (Pat. Pend)

  • Supports multiple languages

    You can select the language from Japanese, English, Chinese, Korean, German, French, and Spanish.

  • Recording and transferring of data
    • The measured values and waveforms can be saved in a memory or transferred out to PC for analysis.
    • Data transfer can be done in the RS-232C to PC.
    • Data can be printed out by the local printer equipped with the device.
  • OptionsDisplay screen
    • The applied force and weld current can be measured simultaneously while welding (Optional weld thru sensor, MA-770A or MA-771A is necessary).
    • Voltage signal (Max.±10V) from other sensor can also be measured due to the external input facility.


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  • Accessories

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[ MM-122A ]
Highly functional and highly precise weld monitor (checker) for various weld current waveforms.

  • Cyclical and accurate display of the welding time for AC inverter welding.
  • Light and compact body. Fast measuring speed, and easy installation.
  • Simple "turn" and "press" operations with a single button.
  • The measuring unit from "ms" or "Cycle" on measuring welding time can be selected.
  • Communication facility is equipped on standard.

    Measured values can be transferred to a PC and the evaluation criteria can be changed from the PC. RS232C and RS-485 are equipped on standard

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[ WM-A728 (Weld checker dedicated to PULSETIG welding) ]

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  • The input/output signal LED indicators on the front panel allows you to grasp input signals to the monitor at a glance.
  • Number of setting conditions: 32 at the maximum (Equipped with a function of copying the setting values to other channels)
  • Simultaneous display of the current and time
  • Enhanced tolerance for noises due to arcs
  • Compatible with mold-type toroidal coils
  • Measurement range setting feature: Performs arithmetic operations and displays the current values in a specified range (Ready for current measurement excluding up and down slopes)
  • AC power supply ready for world-wide use
  • Selectable pulse output time for output signals (TACT, 50ms, 100ms, and 300ms)

[ MM-370C ]

Model MM-370C
Current Measuring range (1)0.1 - 2.000kA (2)0.3 - 6.00kA (3)1 - 20.00kA
(4)3 - 60.0kA (5)10 - 200.0kA
Measured value Arithmetic mean RMS or PEAK
Measurement accuracy For range (1)(3)(5) ± (1%rdg+9 - 20dgt)
For range (2)(4) ± (1%rdg+3 - 7dgt) *1
Voltage Measuring range 2 ranges, 6.00 V or 20.00 V
Measured value Arithmetic mean RMS or PEAK
Measurement accuracy ±(1%rdg+3dgt)
Welding time Measuring range AC mode DC mode
50Hz:0.5 - 500.0CYC/
60Hz:0.5 - 600.0CYC
1 - 2000ms
Force Measuring range 4.90 - 98.06N(MA-520), 49.0 - 980.6N(MA-521),
490 - 9806N(MA-522)
245 - 4903N(MA-770A), 490 - 9806N(MA-771A)
Measured value RMS or PEAK
Measurement accuracy ± (Load cells full scale error +2%rdg+29dgt)
Displacement (option) Measuring range ±30.000
(When sensor with resolution of 1µm or finer is used)
±300.00
(When sensor with resolution of 10µm or finer is used)
Measured value Displacement at end of delay time, start measuring from welding start
Measurement accuracy ±0.05% of full scale
Conduction angle measurement 0 - 180 degree (CYC mode only)
Number of schedules 127 schedules
Printer Printable items: Measurement data, waveforms, all cycles, setting condition data, screen copies, print history
Input power supply voltage Single-phase 100 - 240VAC ±10% 50/60Hz
Power consumption 50W
Mass Approx. 5kg
  • *Specifications subject to change without notice.

[ MM-122A ]

Model MM-122A
Measurement Current Measuring range 0.010 - 0.199kA (Only when 10x sensitivity coil used) 0.100 - 1.999kA 1.00 - 19.99kA 10.0 - 199.9kA
Measured value The peak value of the total welding or arithmetic mean RMS in the measured range can be measured.
Display 4-digit digital display
(7-segment LED)
Measuring range setting Start AC 000-500 cycles (31 conditions) DC 0000 - 2000ms (31 conditions)
End (Supports 50- 250 Hz) 0.50 - 25.00ms(31 condition)
Measurement accuracy RMS ± (2%rdg + 4dgt) *1, 
PEAK ± (2%rdg + 10dgt)
Detection method Toroidal coil
Time Welding-cycle / Pulsewidth Measuring range The maximum measurement duration is 2 seconds. Single-phase AC 0.5-100 cycles (50 Hz)/0.5-120 cycles (60 Hz)
AC inverter type 0.5 - 500 max. cycle (depending on welding current frequency) or 0.50 - 2000ms (until half time of IP for TH)
Display 4-digit digital display (7-segment LED)
Detection method Toroidal coil
Conduction angle Measuring range 30 - 180° Maximum conduction angle within welding time
Measurement accuracy ±5% of full scale
Detection method Toroidal coil
Voltage Measuring range -
Measured value -
Display -
Display -
Measurement accuracy -
Detection method -
Current & voltage measurement value RMS Cycle display: Arithmetic mean RMS for each half cycle. "msec" display: Arithmetic mean RMS per each 1msec
Transistor type: RMS from the start to the end. Capacitor type: RMS from the start of welding to the TH.
PEAK Maximum PEAK during entire welding time
Pressurization Measuring range -
Detection method -
Monitoring Welding current Upper/lower limit 31 schedule setting. Setting range 0 to Maximum measurement range
Welding time Upper/lower limit 31 schedule setting. Setting range 0 to Maximum measurement range
Status alarm display Each dedicated lamp for upper limit, lower limit and "in-rage" will show the status.
Status alarm signal "GOOD", "NG-H", and "NG-L" semiconductor relay
Impulse setting 0 - 9 (Sets the location for measuring pulsation welding.)
Counter 99999 max. 5 digits
Printer Option (BL2-58PN-MYT)
Print-out the following; the current welding time, evaluation result, schedule no., conduction angle and *ACS data counter value been measured and displayed.
*All Cycle Schedule
Step up 11 - 9 steps
Communications output RS-232C/RS-485
The current, weld-time, evaluation results counter value and schedule data measured and display can be transfer in the communication facility.
Power requirements Single-phase 100 - 240VAC ±10% (50/60Hz) or 24VDC ±10%
Mass 1.9kg
Operating ambient temperature 0 - 40°C
Power consumption 112W max.
  • *1: rdg: Read value (2% of displayed measured value) dgt: One count of digital display (3dgt ; There is an error of 3 counts in the final digit.)
  • *2: Projections not included

* Specifications subject to change without notice.

[ WM-A728 ]

Model WM-A728
Toroidal coil TC-M101
Measuring current Range 100A: 0.1A - 99.9A 
200A: 1A - 199A 
300A: 1A - 499A
Value RMS
Accuracy +/- 2% / FS (including troidal coil and monitor)
Measuring time Range 0.1ms to 4.99sec
Measuring voltage Range -
Value -
Accuracy -
Detecting method Dedicated toroidal coil
Number of measuring schedule 32
Power requirements 85 to 250VAC, 50/60Hz Auto-switch, 2A max.
Memory EEPROM memory
Ambient temperature 0 to 40°C (No condensation)
  • MM-370C

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  • MM-122A
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  • WM-A728

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