Mastech MS2115A Clamp Multimeter Review

UPDATE 2018-11

My unit has developed a huge 6A DC current offset a while ago. This is my last sort-of-working Mastech instrument, certainly will not buy anything this brand again.. The warning of wrong banana input started misbehaving in my MS2115A meter. I opened the meter and before I even started to fix, it was mysteriously dead. Haven’t figured it out yet. The HY1803 supply had bad soldering, fixed. Now the current limiting is not working. My AC voltage detect stick went to the trash for being unbelievably unreliable.

Anyway.. the original review:

The Mastech MS2115A is a relatively inexpensive, 6000 count AC/DC current clamp meter with True RMS, Min/Max/Inrush measurement and integrated NCV. There is unfortunately no temperature measurement.

It will replace a $5 living-dead multimeter and a voltage detector in my toolbox. I will not check the precision in this review since it is probably OK out of the box anyway. Only multiple calibrations during a longer time would show the drift. Besides, such tool is more frequently used in troubleshooting where accuracy is not critical. I will update this post with any news.

The specifications can be found here. In short, the accuracy in current measurement is 2.5% ± 6, around 0.8% ± 3 for voltage. I found that different accuracy values are given on the cardboard box and in the manual.

Construction

The body plastic is reasonably solid and has anti-slip coating. The clamp mechanism feels OK. There is little play in the hinge, at least before any real-life usage. The 9V battery door is held with a metal threaded screw – preferable over self tapping screws. The range switch is smallish and may be hard to grasp with gloves etc. The meter beeps on every turn of the range switch – very annoying.

The display is quite reflective. The contrast is good but the viewing angle is quite small, especially viewing from above. Some of the symbols are quite close to the display edge and may be difficult to see. The instruction manual declares 3 updates per second. There is no bar graph. The backlight is white, uniform and bright. In current measurement mode a white LED in the clamp base turns on together with the LCD backlight.

The supplied leads are marked with 600V 10A CatIV. No gold plating or silicone wire at this price point. The package includes the meter, a pair of leads, a canvas carry pouch, 9V battery and operation manual.

The input protection circuit consists of a couple of PTCs. I’m not sure it is safe to use for voltage measurements in a distribution panel. There are three tiny (crappy?) adjustment pots inside.

Operation

• Current measurement goes down to 10mA resolution. A quick check has shown it to be in spec and reproducible even at 100mA.
• Continuity: the buzzer is not latched but reacts fast and sounds nice
• Resistance measurement – I like the Auto ranging speed – it takes ~2.5s for 0Ω. The resistance resolution is 0.1Ω
• Min/Max – the setting also includes a Max-Min option

Non-Contact Voltage Detector (NCV)

There is a handy NCV sensor that gives visual and audible warning. It detects a single 230V outlet from 10cm distance. However, it started alarming from 1m distance from my work desk (lots of live wires around).

Battery Life

The Low Battery warning indicator is shown at 6.7V. Here are the current consumption for some measurement modes, you do the math:

• Current – 12mA
• Voltage, resistance, continuity – 2mA
• NCV – 8mA
• Turning on the LCD backlight increases the consumption by 35mA

 Conclusion

The Mastech MS2115A provides a good set of features for a low price.

Pros:

• Price
• AC and DC current measurement, True RMS
• Handy NCV alert

Cons:

• No temperature measurement

Further Hacking

The main chip markings say F2K2 / DTH0661L. I have not found more info on that yet. I hoped to find the non-mounted USB interface that is present in the MS2115B model. It is a different count meter, so presumably it uses a different controller as well. Another option would be to attach an infrared interface, if possible. There is a mysterious jumper J2 close to the input terminals, but it only outputs a constant voltage. The enclosure seems to have a couple of screw posts where a separate USB interface board would be installed.