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ErnieHorning

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ErnieHorning last won the day on November 3 2013

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About ErnieHorning

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    Apple Valley, MN

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  1. Realize that the fastest that you could trigger a TRIAC is every .008 seconds (60Hz/2). That's assuming that your sequencer sends the command at exactly the right time for one half cycle. It's a good chance that it won't be in sync with the line frequency, so at 60Hz, the TRIAC probably won't actually be turned on. At .016, the TRAIC will always turn on for a at least a half cycle but likely not for a full cycle. You'll probably see a flicker if you kept repeating this. Incandescent lights don't respond this fast. Even at .025, sometimes it will light and sometimes it won't. LED's should work fine at .025 seconds though. Does this make sense? One way to make it work better though is to always do a fad that last at lest .032 seconds or 2 cycles. That way you'll get the light on long enough that it won't be as noticeable. BTW, if the output of your controller was DC, you'd be able to go down to much lower times. LED's should actually turn on and off at .008 seconds.
  2. Actually, technically you could. It would require a full wave bridge before the SCR. You then would have rectified DC and then the SCR would operate with exactly the same end results. Many of the old multi-function strings used this method. It requires one extra part though. You could substitute two SCR’s for a TRIAC but then you would need to drive one of the gates with a negative voltage. Kind of complicates the circuit though when TRIAC’s are so cheap. You can substitute an SCR with a TRIAC since most TRIAC’s will accept both a positive or negative gate voltage.
  3. You really should fire up that scope though. I bet it doesn't work very well if it's been sitting there unpowered for several years.
  4. I should never do this before morning coffee…. Greg is exactly right! Thinking about the LOR supply, I believe it’s a center tap supply. So it will be half the voltage. Max, it really is 60 volts; actually 54 rectified DC.
  5. Nope, it’s the peak voltage. We call it 120 because it’s the RMS value or what the value would appear to be to a resistor in a DC circuit. With your single diode, you basically have a 50% duty cycle DC circuit. Your meter is averaging that to half the voltage. If you just put a capacitor across your meter probes, you’ll see the voltage go much higher. I use 24 volt transformers every day at work. The unloaded voltage is about 26 VAC. Place a full wave bridge on it, add a capacitor 10µF or bigger and you get about 34 VDC not 17. Check your LOR controller. I’m pretty sure that it’s got a 12 VAC transformer on it and a full wave bridge. Check the voltage on the big capacitor. It’s not 6 VDC. BTW, Beckman also makes peak reading meters, at least they used to. We had a few at work that read the line voltage as 177 VAC. It was very confusing, so we ended up just tossing them in the trash. You really should swallow your pride for a moment and try the scope. You could also do a Google search and tell the rest of the world that they're all wrong too.
  6. Geez it really pains me to say this but Max is right. 170 volts positive and 170 volts negative. Greg you really do need to fire up that old scope, those meters are fooling you. Your meters are all measuring RMS and not peak voltage; you’re just seeing the average. Try your meters on a full wave bridge and see what you get. The bridge can’t double the voltage; it just adds the other half of the AC wave to what you get with one diode.
  7. I only put the lights around my shutters but it could just as well go around the window too. I just use 1/2 inch PVC pipe and what seemed like a million wire ties. I’ve made clips that wrap around the pipe and also clip behind the shutters but large wire ties looped through the shutters and around the pipe work well also. Here's a thousand words in a few pictures.
  8. I have no issue with a shield as long as it’s connected only at the source end but not both. I checked around at work and our production controllers do not use ground, only a shield. One controller that’s 400 feet from the computer is double shielded, but again only on the computer end. I’m also one that has both DB25 and DB9 breakout boxes, though I haven’t used either for quite a while. I also remember when The connector was correctly called a DE9. I don’t own one but I did use a HANDSET set coupled modem. I used a couple of telephone books to press the handset in tight; a square peg in a round hole kind of thing. I believe I still have that book around here somewhere. I also have two or three circuit design cook books from the same era. Yeah, I’m afraid I’m older that dirt too.
  9. RS-485 is a standard, not a protocol but that's nitpicking. With respect to what? If you don’t supply a return path, there is no potential difference. Each controller can have its own virtual ground and easily operate with another one. Sure if the voltage was high enough, you could have an inductive or capacitive coupling to earth ground but then you’d have other issues too. I don’t see it as a problem. I see more of an issue in adding the ground on a long run because now you can have a common-mode noise between the ground wire and each individual input wire, nullifying the whole advantage of a differential input. If you’re blowing out a 485 chip, it’s more likely that this is happening because you’re operating in the rain and you had water conduction that by-passed one or more opto-couplers.
  10. The generic DB-9 to RJ-45 is not necessarily very reliable depending on the RS232 port they’re plugged in to. If it’s one that requires no external power supply, it has to derive it from the RS232 port. The RS232 port may not supply enough current to power anything because that’s not what it was intended to do. USB would be a much better choice, even if you had to add a card. Technically you only need 2 wires, "A", "B". Ground is not actually needed. The type cable you use can also make a big difference, especially over long distances. There’s a reason that most people are using CAT5 and not just because it’s cheap. Capacitance can snub the data signal and wrapping braided wire around another one will do so. I’m not saying your wire is bad but if it still doesn’t work, the wire or the RS232 port could be the problem. CAT5 has very low capacitance and goes for thousands of feet.
  11. ErnieHorning

    help...

    Being a DIY kind of person, I look at every problem as an opportunity to fix it. So if the projector doesn’t have an automatic fan controller then it could be fixed in one of two ways. First would be a temperature sensor of some sort and a relay that controls the fan. That way the fan just stays on until the bulb is sufficiently cooled. The second way is a simple time delay relay that keeps the fan on for a fixed amount of time after the power is removed from the bulb. The first way would guarantee the bulb cooled, no matter what the outside temperature is.
  12. ErnieHorning

    help...

    I don’t know why they can’t be turned on/off or why they’re so much different than the bulbs in film and slide projectors of yesteryear or any other incandescent bulb for that matter. It’s just what the people that own these projectors are saying. It wouldn’t be the first time that no one really knew on this site but kept repeating what they heard. It’s just that the life of the bulb is supposedly shortened by turning the light on an off. It’s suggested that displaying a black picture is better than turning the light off.
  13. It could also be a big letdown for you if they release something big and it wasn’t what you wanted. Sometimes, just listening to the voice of your customer can lead you down the path of growth. Not, can lead you into a slow spiral to oblivion. Anyone remember Blackberry? Steve Jobs had the ability to create things that people didn’t know they needed. So far, there’s only been one Steve Jobs.
  14. I normally spend most of my time on the DIY sites and knowing what people are working on is usually not a problem. People will show just ideas or mocked up concepts and in general, what they’re working on. I know it doesn’t work that way with a business. But a ‘Hey were looking to come out with ‘X’ sometime in the following year or two’. would be nice but I understand why they won’t too.
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