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Hardware Gallery
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A lot of my most interesting hardware design work occurred before we switched to using digital cameras and started photodocumenting everything. I did manage to get a few shots of some automated pressure test systems that we designed and built for major medical device manufacturers, back when we had our office in Sandy, Utah in 1999. These were taken in our shop area during construction and start-up test. In the foreground is a small lab test bench for comparative dynamic evaluation of intrauterine pressure test transducers. In the background is a production test system for intracranial pressure test transducers. |
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This bench test system used a National Instruments data acquisition I/O module with a Tescom PID pressure controller, programmed through an RS-485 link. |
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This production QC Test system was based on an Agilent (then HP) 34970A multimeter/scanner unit, programmed through a National Instruments GPIB interface. |
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The apparatus in the picture on the left, believe it or not, was the "temperature chamber". These tranducers were tiny catheter-tipped microsensors, and their tip temperature was controlled by a highly insulated aluminum block that was heated and cooled by a thermoelectric controller Peltier cooler (TEC), driven by an analog PID electronic control module mounted directly underneath. The temperature control operated over the range of 10-50 °Centigrade and was extremely fast. The reference thermistor-based accuracy (obtained through custom curve fits) was on the order of .05°C, which was as accurate as we had the means to calibrate. Repeatibility in temperature control was on the order of .005°C. |
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| The picture on the right shows the back of the console, including the custom bridge amplifier test board that I designed. It was capable of providing bipolar, continuously variable constant current or constant voltage bridge excitation completely under program control. This allowed us to do extremely accurate uncompensated sensor gain and bridge resistance profiling for compensation purposes. |
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| As I've mentioned elsewhere, I don't do a lot of control panel assembly for my automation clients. My electrical designs are often melded in with a lot of other existing stuff on-site, so to represent that work as my own isn't appropriate. I actually have done more electrical hardware design and assembly on the PV installations that we did in the past few years, which you can see in the solar gallery pages, but those pictures don't really show the internals. Anyway, here are a couple of fairly simple data logger and combiner/switch enclosures that we have built and installed.
PV Monitoring System - Cypress Semiconductor, San Jose Califonia (PV system itself installed by Powerlight Corporation)
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Display in the main lobby of the building. This display was driven by the Campbell CR10X data logger you see in the picture immediately below. |
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This box was located in the utility room where the array combiner was located. The front panel display was programmed to visually display the currents from selected individual strings of solar panels, based on a stream of data transmitted from the CR10X. |
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Inside the datalogger assembly box. |
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Inside the PV combiner box. If you look closely you can see the hall-effect sensors used for DC current monitoring, mounted on the red wires. |
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Here's a couple other simple combiner and data logger enclosures. |
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| If you're interested in seeing the scope of the control panel layout and wiring design that I do, let me know and I can send you some representative samples in Autocad format. I prefer not to post my client's design documents on a public site even when there are no confidentiality issues, and simple web images of detail drawings just don't render well on a web site. |
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