Voltcraft VC-870 Multimeter Used With UNI-T UT-D04 USB Cable

Target hardware:

• VOLTCRAFT VC-870 Multimeter
• UNI-T UT-D04 USB Cable

Software repository location:

• https://github.com/jsyk/VC870_USB_Datalog

The issue this software solves: Although the Voltcraft multimeter and the UNI-T USB cable are  hardware compatible (the USB cable adapter fits into the multimeter connector perfectly), the software requirements are different. Original Voltcraft USB cable, which costs tripple the UNI-T cable by the way, mimics RS232 adapter when plugged in USB host PC. The UNI-T cable uses different chip internally and behaves like a HID device. On the other hand, UNI-T multimeters use different communication protocol over the serial line than the VC870 does.

This software package is composed of two independent parts: 1. USB cable interface in the utd04-cable directory, 2. multimeter protocol decoder in the vc870-decode directory.

The USB cable interface is adapted from other work, see copyrights in the directory. Compile according to instructions in the utd04-cable/readme.2.txt file.

The multimeter protocol decoder is a perl script. Use in a pipe together with the cable interface:

./utd04-cable/utd04-cable -b9600 | ./vc870-decode/vc870-decode.pl

The above commands need to be run under root (su) because of USB access permissions required in the cable interface program.

Note that I have not tested the protocol decoder extensively, there may be bugs (particularly in range decoding).