19″ Rack Mount Project

Yes, I have some kind of a Gear Acquisition Syndrome. Yes, I’m a Test Equipment Anonymous. Yes, I love Test Equipment! 🙂 However, this was bothering me for quite some time. The 19″ equipment was laying all over the place and I had some difficulties using it, since the instruments were bulky, scattered and there was no logical order as soon as I wanted to perform measurements. Luckily, a colleague of mine gave me a hint to buy a very cheap 19″ (42 HU) rack mount. This would solve few problems and also introduce new ones (more space for more equipment! Just kidding…). Anyways, I bought the rack mount and after few weeks of procrastinating, I finally equipped it with my 19″ sized test equipment. I’m pretty happy how it turned out. The most heavy parts are located at the bottom and lighter equipment is located at mid to top. It’s stable enough and won’t tip over and it can be easily moved around.

Almost all instruments can be controlled remotely either via GPIB or RS232. An older Dell Workstation will be controlled via Windows Remote Desktop. Instruments from top to bottom are listed as follows:

• HP 3325B – A 20 MHz frequency generator with some interesting features for audio testing
• HP 3488A – Switch unit equipped with different modules. It’s used for automated, accurate and reliable signal switching or signal routing – it really depends on the used relay cards. I got few of them over the past years, e. g. types 44470A (10 CH multiplexer), 44471A (10 CH general-purpose relay module), 44472A (dual 4CH VHF switch module), 44473A (4×4 Matrix switch) and 44474A (16 bit digital I/O)
• NI BNC-2090 is coupled with NI PCI-6110 (PCI multi-function-I/O-card with 4 analog inputs (12 bit, 5 MS/s per channel), 2x analog out, 8 digital I/O)
• Tektronix TDS 644B, 4 CH, 500 MHz, 2 GS/s digital real-time oscilloscope. It’s a bit overkill for my audio-type applications – an excellent instrument for displaying waveforms, even RF stuff. A very useful feature is a GPIB interface for remote control and screenshot hardcopy (no need to use the disk drive)
• Dell Precision T5400 workstation PC. It’s a 2007 era workstation which I bought probably around 2010 as a second hand PC. I used it like… forever. It was replaced by a faster workstation back in 2020. I haven’t dumped it because of the DVD burner and slots for 3x PCI and 3x PCIe cards. This makes it very valuable when it comes down to using data acquisition PCI cards from early to mid 2000’s era with a Win 7 or Win 10 operating system. Unfortunately this unit consumes a lot of power – it tends to heat up and it’s having thermal management difficulties during hot summers. Few of the ECC SD-RAMs failed over the past years but luckily they have been replaced easily. I tried to equip the three PCI slots with my oscilloscope cards, however, there were some serious thermal issues. I didn’t want to fry the cards so I put them inside of an external PCI expander system
• Sun Microsystems Netra E1. After having thermal issues and space problems inside of the Dell T5400, I was looking for a better solution to put the cards in a separate chassis and operate them via a PCIe/PCI bridge. Few solutions exist today, however only few are viable due to hardware/driver compatibility or power delivery constrains. The cheap expansion cards (mostly from China) can’t always deliver the 25-75 W of power to the oscilloscope card. In my case, as soon as the oscilloscope card demanded more power, the PC system crashed. After browsing eBay and looking for National Instruments’ “PXI-like” external chassis solution, I found Sun Microsystems’ Netra E1 as a viable option – however, the price was hefty. In retrospective, I’m glad I bought it because it was ready for use and it saved me a lot of time and trouble. The installation was super easy as PCI/PCIe bridge drivers exist at least since Windows XP. A downside of Netra E1 are the really loud fans. They work relentlessly at full speed; however, they keep the power-hungry cards at acceptable temperatures around 50-60 °C in comparison to 75-80 °C inside of Dell T5400!
  

  

  

  

  Unfortunately, Netra E1 is obsolete technology and no replacement parts exist on the 2nd hand market. Those units were produced around the year 2001 as an expansion system for Sun’s Netra Servers. I might be wrong about this but IIRC their PCI expansion product line was acquired by a company called MAGMA somewhere around mid 2000’s. MAGMA was specialized in building PCI Expander Systems for the Pro Tools Digital Audio Workstations (Pro Tools by Avid Technology, famous tor their audio/video editing software). eBay has some offers with MAGMA expansion chassis up to 16 PCI card slots, however they come at an unrealistic price of $500 to $1000, at least for a hobbyist budget. Anyways, beside the three existing PCI slots inside of the Dell workstation, I was able to put all of my four “power hungry” PCI cards (full length) inside of the 19″ chassis

  • NI PCI-6110: multi-function I/O card
  • NI PCI-5105: 8 channel, 12-bit, 60 MS/s digitizer/oscilloscope with up to 60 MHz analog bandwidth
  • NI PCI-4461: dynamic signal analyzer, basically a $10k sound card, still produced today – according to NI, it can be bought until 2024-12-31!
  • Agilent/Acqiris AP200: 1 channel, 500 MHz, 2 GS/s high-speed digitizer/averager card (used in radar tech or mass spectrometers)
• Yokogawa/HP 4274A Multi-Frequency LCR Meter. I have a bunch of HP fixtures for components, unfortunately the LCR meter needs a repair. Should be hopefully an easy fix since the errors appear after warm-up. Fun fact: The Japanese government was very restrictive and protected their markets in the early days. In order to enter the Japanese market, companies from foreign countries such as United States were obliged to “team up” with a local Japanese manufacturer so they could sell their products in Japan. I guess HP teamed up with Yokogawa and Tektronix had a partnership with SONY. That’s the reason why there is occasionally a double company logo on some pieces of test equipment.
• Tektronix TM5006 chassis equipped with
  • Tektronix FG5010, 20 MHz frequency generator (GPIB-controllable)
  • Tektronix AA 5001, audio analyzer capable of measuring Total Harmonic Distortion (THD), also GPIB-controllable
  • Tektronix SG505, audio frequency generator with exceptional ultra-low distortion sine-waves, perfect for audio amplifier testing
  • Tektronix DC 503, digital counter (doesn’t work, needs a repair)
• HP 3562A Dynamic Signal Analyzer. A very capable FFT analyzer e. g. for audio and vibration testing and frequency response analysis in the µHz … 100 kHz regime
• Fluke 5100B/5101B Calibrators. They can provide AC and DC voltages and currents and also resistances for calibration of up to 5.5 digit DMMs. Unfortunately, both need repair (power supply issues). Currently they are not in use – I’m hoping to repair them either later this year or maybe in early 2025

Surrounded by the rack mount are my book shelves with many books about physics, chemistry, operating systems and other stuff. A HPM 7177 digitizer can be seen at mid-left. There are only three cables left which are connected externally to the chassis: 230 V power, GPIB and Ethernet. I could replace GPIB with an NI GPIB-USB and Ethernet with WiFi. This would of course simplify the cable management but I’m very happy how everything turned out. I’ll need to find some lifting feet for the rack mount since it’s a bit overloaded with ~200 kg of equipment and it could cause damage the floor and the wheels over time.

Most of the test equipment seen here has been acquired during the past 3-4 years. Some pieces were really cheap (< 100 EUR), others rather expensive (> 300 EUR). It will be used for my laser interferometer and accelerometer calibration project which I plan to build in the future.