HF71 – Custom RS232 Cable for IS33

Having worked in an ISO 17025 calibration lab, I get to see a lot of different and fancy test equipment. The Crystals are hands down my favourite pressure calibrators. They last forever and are usually within tolerance as found. Since they last so long, there’s still a good deal of these IS33 pressure calibrators out there that has the odd ball custom RS232 serial connector. This makes setting the calibration date and span adjustment a bit of an issue. The PN 1928 cable is VERY hard to come by and basically impossible to purchase. I got to thinking and found that I could make my own custom cable that is compatible with the PN 1928. This is my first custom cable and I’m very happy that it worked out. The working cable you see in the photo is a third iteration that uses a standard RS232 serial connector, Ethernet cable and a modified SATA power connector.

HFX – Electrical Test Set


Hui Gardens HFX electrical test set is the fusion of several basic electrical things that I’ve built while making other electronic things. It combines my HF1 – 100W Resistor Box, HF11 – 2 Wire RTD Simulator, the most useful parts of the HF2 -24V Variable DC Power Supply and more! I decommissioned the mentioned prototypes and repurposed almost all the parts including wires and resistors.

The Hui Gardens HFX features the following:

  • 24V adjustable DC power supply from 4x AA batteries (easy access) to loop power 4-20mA transmitters
  • 100W resistors including a 270Ω (close enough to a 250Ω resistor) for HART communication
  • 10 turn 2W potentiometers to allow for RTD simulation and 4-20mA simulation
  • 10W shunt to allow for high current measurement
  • Relay to take input and switch loads on and off and allow triggering of a frequency counter to test timing
  • 0.75″ spacing standard between banana jacks for double banana leads

I wanted something that can carry my Fluke 87V multimeter and be useful for things I test on a regular basis. I took a design cue from some of the high voltage equipment I see that allows for the meter and test leads to be stored in one case. Having a separate lead bag is really cumbersome and is prone to getting lost. I really like the brass wingnut chassis ground aesthetic. If it’s good enough for a 120kV hipot, it’s good enough for me!

Housed inside a Nanuk 920 hard case with a cut aluminum panel kit, the Hui Gardens HFX is pretty tough. The big red toggle switch cover is a must, the Chairman Mao emblem is an especially nice touch, but the best part is the custom 3d printed nameplate in brass.

3D Printed Custom Name Plate

After having some 3D printed metal pieces from Shapeways.com under my belt, I felt fairly confident with my settings to get legible engraved text. So, I decided to try my hand at having a custom name plate 3D printed for a new electrical test set (Hui Gardens HFX) I made for my Fluke 87V multimeter. This one is in brass and has both engraved text AND an embossed element. It’s got English, Chinese and a custom logo. Costing about ~$35 CAD plus shipping, it’s not bad considering the quality and customization I’m getting. WAY cooler than plain printed text on a metal blank. You can feel the letters on this custom name plate. I chose brass, because it’s a fairly inexpensive metal and brass doesn’t spark when struck (not that it matters in this case) and I see lots of brass being used on HV test equipment I come across. It’s more for aesthetics, but it looks like it belongs.