V&A VA18B

Mastech VA18B

The Mastech VA18B a.k.a. V&A VA18B (V&A is a brand of Mastech) is a CAT II (1000V) handheld digital multimeter with USB connectivity.

See Mastech VA18B/Info for more details (such as lsusb -vvv output) about the device.

Model overview

It seems there have been at least two different revisions of the multimeter (or at least of the PC-Link cable). The older one used a Sunplus SPCP825 USB-to-serial chip (see here, also the software from here), the newer revisions use a Prolific PL2303 chip. Both should work fine with sigrok, as long as the respective driver creates a "virtual COM port" / serial port device sigrok can connect to.

Device	Rebranded?	PC interface chip	Vendor software	Comments
Mastech VA18B (old)	no	Sunplus SPCP825	"PC-LINK"	—
Mastech VA18B (new)	no	Prolific PL2303	"PC-LINK"	—
Velleman DVM1200	yes (VA18B)	?	"PC-LINK"	—
Maxwell MX-25328	yes (VA18B)	?	"Maxwell Universal Program"	Maxwell wrote their own PC software, apparently (works fine with the VA18B if you select "25328" as device in the software).
Peaktech P3375	likely (VA18B)	?	?	Very likely a rebranded Mastech VA18B (1, 2, 3).

Hardware

Multimeter:

• ...

USB cable:

• Prolific PL2303HX YR0903A
• 12MHz crystal

Photos

• 

  Device, front

• 

  PCB, front

• 

  PCB, back

• 

  USB cable

• 

  USB cable PCB, front

• 

  USB cable PCB, back

Protocol

14-byte LCD segments over USB-2-serial (Prolific PL2303 chip, 2400 baud, 8n1), see various links below.

To enable output to the PC on the multimeter you have to keep the "Hz/DUTY" key pressed while powering on the device.

Resources

• Protocol descriptions: [1], [2], [3]
• EEVblog forums: Product review: DMM latest V&A Mastech VA18B