Advice needed - regarding use of optical encoder. - Electronic Circuits Projects Diagrams Free

Denniswho · 9th April 2006, 04:30 PM

Hi... I need to replace an obsolete shaft actuated mechanical counter on a piece of machinery. I wanted to do this electronically and was actually thinking about building some sort of counter/sensor setup. Thanks to E-Bay, I was able to purchase a few goodies to get me started. I obtained an Eaton/Durant model #5781-0 Digital Electronic Counter/Display Module that I'm trying to interface with an Oak-Grigsby #96Q100 Optical Encoder Unit. Both items are dual quadrature and will count pulses up and down to display the relative position of a threaded adjustment shaft. The encoder unit has integral/sealed LEDS and Schmidt trigger photo-transistors with resolution of 100 pulses per revolution and good for up to 3000 RPM's. However, the threaded shaft will only be hand cranked and the return to a specific number readout and memory will enable repeatability of precise manual position settings. The display unit has a +15 VDC output terminal referenced to a GND terminal. This is normally used to directly power a 15 volt optical encoder unit. The encoder I have is rated at +5 volts MAX. Therein lies the problem! I fabricated a simple 7805 regulator circuit to satisfy my 5 volt encoder requirement. I then used each A & B encoder output lead at a pulsing 1.2 to 5 Volts to switch the +15 volts through a 2N2222 NPN General Purpose Transistor in a non-inverted fashion for input to my display A & B input terminals. This circuit doesn't seem to function properly. Instead of swinging from 0 to +15 volts - My circuit is swinging from +5 to +14 volts. So-far, the display isn't counting or registering any pulses. The transistor is biased with a 4.7K resistor. A load resistor of 4.7K is used on the collector as well. AFTER A RATHER LONG-WINDED explanation, I was wondering if any of you "experts" can suggest an alternative method for adapting these components to each other. After years of careful and diligent non-preparedness, I am about as non-expert as one can be. I read and attempt to learn as I go and that ususally works in most situations. However, I am steadily loosing self-confidence and the need for outside intervention is imperative. Please help.

ljcox · 10th April 2006, 01:34 AM

I suggest you post a circuit, I (and I suspect others) don't have the time to wade through your description and understand it to the point where we can give advice.

A picture is worth a 1000 words. It can be simply a hand drawn scanned one if you don't want to draw it in PowerPoint or other drawing package.

tkvenki · 10th April 2006, 06:19 AM

Quote:

A picture is worth a 1000 words

I completely agree with ljcox

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9th April 2006, 04:30 PM	(permalink)
Denniswho	Advice needed - regarding use of optical encoder. Hi... I need to replace an obsolete shaft actuated mechanical counter on a piece of machinery. I wanted to do this electronically and was actually thinking about building some sort of counter/sensor setup. Thanks to E-Bay, I was able to purchase a few goodies to get me started. I obtained an Eaton/Durant model #5781-0 Digital Electronic Counter/Display Module that I'm trying to interface with an Oak-Grigsby #96Q100 Optical Encoder Unit. Both items are dual quadrature and will count pulses up and down to display the relative position of a threaded adjustment shaft. The encoder unit has integral/sealed LEDS and Schmidt trigger photo-transistors with resolution of 100 pulses per revolution and good for up to 3000 RPM's. However, the threaded shaft will only be hand cranked and the return to a specific number readout and memory will enable repeatability of precise manual position settings. The display unit has a +15 VDC output terminal referenced to a GND terminal. This is normally used to directly power a 15 volt optical encoder unit. The encoder I have is rated at +5 volts MAX. Therein lies the problem! I fabricated a simple 7805 regulator circuit to satisfy my 5 volt encoder requirement. I then used each A & B encoder output lead at a pulsing 1.2 to 5 Volts to switch the +15 volts through a 2N2222 NPN General Purpose Transistor in a non-inverted fashion for input to my display A & B input terminals. This circuit doesn't seem to function properly. Instead of swinging from 0 to +15 volts - My circuit is swinging from +5 to +14 volts. So-far, the display isn't counting or registering any pulses. The transistor is biased with a 4.7K resistor. A load resistor of 4.7K is used on the collector as well. AFTER A RATHER LONG-WINDED explanation, I was wondering if any of you "experts" can suggest an alternative method for adapting these components to each other. After years of careful and diligent non-preparedness, I am about as non-expert as one can be. I read and attempt to learn as I go and that ususally works in most situations. However, I am steadily loosing self-confidence and the need for outside intervention is imperative. Please help.

10th April 2006, 01:34 AM	(permalink)
ljcox	I suggest you post a circuit, I (and I suspect others) don't have the time to wade through your description and understand it to the point where we can give advice. A picture is worth a 1000 words. It can be simply a hand drawn scanned one if you don't want to draw it in PowerPoint or other drawing package. __________________ Len