Electronic Circuits and Projects Forum

Razeen,I have a difficult time explaining. SO....... i will begin new, the process. push button(leaves home switch inverted setting the s-r latch......... ) then oscillator needs to be variable for feed. Limit reached...... Pause 5-10 seconds, then speed home.( maximum speed for stepper motor without ramp up, {I dont think anyone here could make ramp up oscillator?} well maybe you? in theory a large cap and a small resistor could create a voltage controled osc.? .........I dont need that part though....
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So answer to your question CMOS logic and low speed variable by user. high speed one time adjust to equiptment needs.

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Crosslakeguy,
I gave up on you because you keep going off on tangents.
I told you that a 4066 would work. I don't think you ever believed me.
Alec showed you how to use them. You pretty much ignored him.
I asked you here for details. You promised to get back with them, but never did. I was going to design a circuit that requires no analog switches or relays.

I haven't used digital pots. I could figure out how to use one from the datasheet.
A digital pot can be used as a rheostat, but there are a lot of details to attend to. Low-cost units have huge resistance tolerances, like ±20-30%, and resistor tempcos of 200-300ppm/°C. You can buy low tolerance, low tempco units, but they are relatively expensive, and have peak current specs that have to be adhered to.
You can use a low-cost unit for your application in ratiometric mode, which is what they are designed for, but it would require more parts, like an op amp, a transistor, and a couple of resistors.

Please tell us the high and low frequency ranges, in hertz (not rpm).

EDIT: This forum appparently will not allow shouting. I typed the above sentence in CAPs, and it converted them to lower case.
Sometimes SHOUTING is appropriate - like now.

Hey, so low 100hz- 330hz and high 330hz- 1.167khz. an active low will run low, an active high will activate high. the high speed and low speed run the same motor. those numbers don't need to be exact, It is just what the rpm's worked out to. the low numbers are definite values. The high could possibly be from 600hz to 1.2khz as I probly wont use between 330hz- 600hz anyways? the speed increase could be as high as 25hz incriments, lower would be better. when I get back home I will be ready to try these disigns, yes Alecs too. which I do have a couple questions about as well. post #1 I should have devided by 60 not multiplied, oops. no wonder you are asking........ Sorry! p.s I looked back at the digital pots spec. sheet, like you said +20 to -20% wow! It would still work for me...... but wow!

I'm assuming that duty cycle is unimportant. Is this true?

yes, for the most part, the circuit I made the duty cycle was to long...... so I inverted the signal. I don't remember the specifics, but a shorter duty cycle functions better than a longer one. the circuit recognized a pulse better than a long duration on time.. but I think a square wave is fine too?

Limit,HOME...... Yes that would work, however It must always know where home is....... on startup .or mid-cycle start.......cannot assume always at home position. like a printer. cycle on..... find home....... all values assumed after that 1000 steps is 1000 steps. I understand what you are saying but is this possible without a microcontroler? as I said efore I am running this currently on a cnc program called MACH3....I bought a PIC programming book, but without personal help it is way to complicated for me to understand? I have looked at basic programs and others, I wish I understood them?....... thats why I am trying to do on off type circuit? and yes Idealy I could adjust the pulse rate and number.........and if pigs could fly.....a ramp up frequency on high speed.\ for return to home/ the more I try to learn, the more I undertand that I don't know....