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  1. Minder

    Optical Encoder Issue

    The 'Encoder' appears to be a home made slot opto and a quadrature strip, If so for bi-direction you need two detectors. But these usually have fairly low in/out impedance, did you provide a suitable value for pull up on the output? I am guessing that your problem lies in this area, still no...
  2. Minder

    Optical Encoder Issue

    Without having the unit to test I can neither confirm or deny it is P.S. or other noise. It is mainly a question of taking one of the actions shown above in order to eliminate it. There is a part of the circuit that appears susceptible to radiated (AC) noise. If you post the circuit, it may be...
  3. Minder

    Optical Encoder Issue

    Not quite sure what you mean by 'floating neutral' but the live and N are normally isolated from the output, but in some cases input filter components can be also be connected from AC to output. Only a test would find out if a better SMPS supply would work. I don't there would be any future in...
  4. Minder

    Optical Encoder Issue

    With earth grounding it does not matter if you earth ground the +ve or the common, they are identical as far as noise is concerned. Especially when de-coupled by a large Cap. It does seem like radiated noise from the external AC. I assume that P.S. is a SMPS supply, I would bet it may not happen...
  5. Minder

    Mosfet heater control

    If it was switched on/off with a very brief period there would be no time for the heater to drop in resistance, also a zero crossing SSR could be used. M.
  6. Minder

    Optical Encoder Issue

    Is this an off the shelf board or your own? M.
  7. Minder

    Optical Encoder Issue

    I too would say a grounding issue, I see you are using a Wall Wart, try it with a battery. Also if it persists, try an earth ground to supply common. Also try local de-coupling, place a small electrolytic across the supply terminals. M.
  8. Minder

    Book Reviews

    On an allied note, my first go-to for books is AbeClearing House, I have had a real good deals on $$v'e books, some with the accompanying CD unopened. http://www.abebooks.com/ M.
  9. Minder

    20 ohms

    On an AC inductive device at switch on, the current is dependent on whatever the DC resistance of the device is, this resultant high current occurs for a fraction of a second, less than 1 cycle, fuses and breakers have a certain time delay which does not respond to this, after this inrush, the...
  10. Minder

    1600W heat using weight sensor

    How much do you want to go in the design process. You could use a load cell, they a couple of $ on ebay. If you want to control the degree of heat. See Microchip MCP3421 weight scale app includes software. For simple heat on/off use a load cell and set a comparitor to detect if for a certain...
  11. Minder

    voltage dropping

    Is that .2 ma or 200ma. So Series R will need to be 35ohm for minimum Zener current so 27ohms should do it. 7/.2 = 35. Or if .2ma then 35k or 27k for optimum. Probably need to go to a lower value to reach forward current breakdown region for the zener. M.
  12. Minder

    voltage dropping

    In using a zener you will need a resistor and 5v zener in series wired across the supply source, then take the 5v from common and the cathode of the zener place an electrolytic cap across the 5v.. Zener regulators are practical if the If the current draw is minor. M.
  13. Minder

    Need Help regarding 12v DC Motor

    REd = Re-Engineered? M.
  14. Minder

    Need Help regarding 12v DC Motor

    Not only is the motor unsuitable for this application, they are intended to be ran at much higher rpm's than practical for a pump. The pump example you show is probably a 3ph 4 pole or even 6 pole induction motor. M.
  15. Minder

    20 ohms

    Yes. It is normal to see very low resistance when measuring a non powered inductive device. A extreme prime example is a induction motor, not only is there the initial low resistance of the windings, but when powered the 'secondary', (rotor) appears as a shorted turn secondary to the stator...
  16. Minder

    help finding connector name/item number

    All kinds in DigiKey. I'm sure they would be avail. in UK also. M.
  17. Minder

    20 ohms

    In a AC motor circuit/solenoid/contactor coil , the Only time the circuit 'see's' the device resistance is at the point of switch on for a fraction of a second, after this the current is limited by the Inductive reactance of the motor etc which is much higher than the measured resistance by ohm...
  18. Minder

    CNC Machine Help

    Similar as when I set a mill or gantry machine up for individual as well as All-Axis option homing routine, I make sure the Z homes first and then XY together.. M.
  19. Minder

    CNC Machine Help

    Correction, my mind was else where, the standard Cartesian coordinates is of course the Z moves UP in the +. Also in my opinion the initial Z should be positioned First to a posn above the work before the XY move, the Z could be at any position at that point. If unsure where the +Z is needed, do...
  20. Minder

    CNC Machine Help

    Would need the relevent G-code for that portion of the move. If the top of your board is 0, then the tool requires a move in the minus to clear the board. M.
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