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Recent content by mwebster

  1. mwebster

    Need to home to a middle position

    It's going to be driven using custom software on a PC. I suppose I could force write unbuffered positional data down to the hard drive. This might be a decent solution now that I think about it. The only thing this should miss is if the actuator was moved manually while the power was down...
  2. mwebster

    Need to home to a middle position

    Greetings, The synopsis: I'm trying to figure out how to home a linear actuator to a point approximately halfway between its two extremes. Pertinent details: The device is driven by a precision linear actuator with a movement per step of 1.5 microns (the linear acutator is driven by a stepper...
  3. mwebster

    Anyone know of a prefabbed TVS array with screw terminals?

    I've got a TTL level digital input card that's started popping channels. I suspect a wiring fault in our cabling or test unit is temporarily tossing 24VAC onto the input line which the input card can't hold off. So, I'm looking for a protection solution somewhere this side of full-blown...
  4. mwebster

    chip antenna vs meander antenna

    I went through this a few months ago. Trace antenna's take up more board real estate but can be significantly better than a chip antenna if tuned properly. You need to look not just at the board space available but also what the enclosure is going to look like, how close it comes to the board...
  5. mwebster

    Labview with data analysis

    I haven't used that particular device, but they have Labview drivers according to their website. Assuming that those drivers work properly, then yes, Labview can be setup to display the captured values pretty easily. The ability to quickly get a graphical UI with graphs and different sorts of...
  6. mwebster

    Load Bank Transistors Blowing out.

    Thanks for the replies. No, I haven't checked the temperatures yet. This is for a client who's some 5 hours from my office, so it's pretty much an overnight visit when I go down there. I haven't dealt much with high power installations, so I wanted to get all my ducks in a row before heading...
  7. mwebster

    Electrical Calculation Software

    I should mention that there are caveats and downfalls for all circuit simulators out there. In a lot of cases, you have to be careful to model in parasitic inductance, capacitance, and resistance, especially when using the basic "ideal" elements. Voltage sources, capacitors and inductors...
  8. mwebster

    Electrical Calculation Software

    Free: LTSpice Easy(ish): NI Multisim (formerly Electronics Workbench) Standard: Orcad PSpice A good option for simple circuits is Paul Falstad's circuit simulator (here - 5th section down under Electrodynamics). The UI is pretty crappy, but it's the best thing I've come across for visualizing...
  9. mwebster

    Load Bank Transistors Blowing out.

    I've been working on reverse engineering a resistive load bank control board that controls a 750 Amp load bank. My problem is that I don't see how the trim transistors keep popping. Here are some of the fun details: The board controls and trims a set of amplifiers that work to turn on the main...

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