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Hi Everyone
I have an idea about a simple encoder feedback for stepper drivers and I need some help and ideas. It may help you also. I was thinking of using a PIC like 16F84 to look at the Step signal and look at the encoder feedback to compare the two just as a single step so it dosen't get complicated. Secerio like this: Computer steps ones the PIC looks at the encoder did it step? YES/NO If no then pulse one extra step to the step input on the controller,,,if stepped like 10 times no movement then and error LED lights up or whatever. Any help Ideas? Dennis Izoita |
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PIC Stepper Motor Encoder Feedback
Started by ●August 17, 2003
Reply by ●August 18, 20032003-08-18
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You could setup a timer0 interrupt and a r/b change interrupt. Poll for which interrupt occurred. The timer0 would be your timeout, if in X amount of time no steps, do this. The r/b change would count the number of steps. Or compare the input to output, etc.
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Hi
Everyone
I have an idea about a simple encoder feedback for
stepper drivers ">Yahoo! Terms of Service. |
Reply by ●August 18, 20032003-08-18
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I detect some basic problem here. Two major reasons for using a stepper motor rather than a servo motor is simple drive circuitry and no need for position feedback. If you still need to go this way, the encoder will have to be matched to the stepper motor physically or the resolution of the encoder will have to be at least twice the step size. Maybe what you really need is velocity feedback? Chad --- In , "Dennis " <dizoita@y...> wrote: > Hi Everyone > I have an idea about a simple encoder feedback for stepper drivers > and I need some help and ideas. It may help you also. > > I was thinking of using a PIC like 16F84 to look at the Step signal > and look at the encoder feedback to compare the two just as a single > step so it dosen't get complicated. > > Secerio like this: Computer steps ones the PIC looks at the encoder > did it step? YES/NO If no then pulse one extra step to the step > input on the controller,,,if stepped like 10 times no movement then > and error LED lights up or whatever. > > Any help Ideas? > Dennis Izoita |
Reply by ●September 1, 20032003-09-01
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--- In , "Dennis " <dizoita@y...> wrote: > Hi Everyone > I have an idea about a simple encoder feedback for stepper drivers > and I need some help and ideas. It may help you also. > > I was thinking of using a PIC like 16F84 to look at the Step signal > and look at the encoder feedback to compare the two just as a single > step so it dosen't get complicated. > > Secerio like this: Computer steps ones the PIC looks at the encoder > did it step? YES/NO If no then pulse one extra step to the step > input on the controller,,,if stepped like 10 times no movement then > and error LED lights up or whatever. > > Any help Ideas? What you really need is NOT to send more pulses to the driver if the motor hasn't completed the step. The correct scenario is as follows: 1. The computer sends a pulse to the PIC and the PIC passes this pulse to the driver. The PIC increments a counter to count this pulse. 2. The PIC waits for the encoder to detect the rotor movement. If an encoder pulse is detected, the counter is decremented back to zero. 3. If another pulse from the computer arrives before encoder movement is detected, the counter is incremented but no pulse is passed on to the driver. 4. If encoder movement is detected, a pulse is outputed to the driver and the counter is decremented. 5. If the motor is stalled, the counter will accumulate pulses until it overflows and an error led is turned on. |
