Hi, can you help me with the arduino code? i want to make a similar project, but in Brazil we dont have all the parts you used, i want to use a stepper motor, arduino Uno, keypad 16x16 and 2x16 lcd... with endstops... can you tell me if the code is just change the pins ? or the servo you used is diferent then pulse dir of steper?
Thanks! The ClearPath servo is capable of setting home once it hits a hard stop. When the system initializes, it drives the carriage slowly until it contacts the very beginning of the actuator. That action sets the home position. Thanks for watching and commenting.
Love what you have done here. Is there a way to make it as metric instead of imperial. I am very new to Arduino but this would be awesome to have in our workshop???
Hi MySchizo Buddy, Neo7CNC asked Teknic to chime in on this question since this video pertains to ClearPath specifically. You asked a similar question on a Teknic video as well, so I have posted my response on both videos. To help other viewers, I've copied your question (and my response) from the Teknic video below: ua-cam.com/video/-gigcf7ZzAQ/v-deo.html&lc=z23bgldwgxesgxjtbacdp43bv0jilo1th3blon2qaftw03c010c _"There is a confusion about homing. Some youtubers say because of the encoder in clearpath servos you don't need homing on cnc machines. The encoder always knows where it is. While others say that if you turn off and on the cnc machine then you do need to home the machine. What about proximity switches? Do cnc machines need them with clearpath servos?"_ These are good questions, but some that require a longer response and additional background, so I apologize in advance for the long post. Generally speaking, most encoders are categorized into one of two types: absolute encoders or relative encoders (also commonly known as “incremental” encoders). At a high level, the two types serve the same function (they provide position and velocity information back to the servo drive), although there are some notable differences. Absolute encoders provide unique positional information throughout the entire range of the encoders’ travel. These encoders don't usually require homing because you can “read” the position at any time and know where you are (although you still need to correlate a specific absolute position to a specific location on the machine). Please note that we further differentiate absolute encoders by the number of “turns” they can experience before they are no longer “Absolute” because the encoder’s position wraps (more on this later). You can identify the two types as “single-turn” or “multi-turn” encoders. On the other hand, a relative/incremental encoder needs to be "calibrated" or "homed" initially. An incremental encoder outputs electrical "pulses" as it rotates, and it's the servo drive's responsibility to monitor and count these pulses to keep track of how far the encoder has traveled. In order to translate this distance traveled into an absolute location on your machine, the servo drive needs a starting reference point (or "home" location). I.e. the incremental encoder is telling you how many counts away from "home" the system has traveled. So, since an absolute encoder doesn't generally need to be homed, you might wonder why anyone would use an incremental encoder. While there are a number of cost and performance benefits to incremental encoders, absolute encoders can only register their absolute location within a finite number of revolutions. If your application exceeds the number of revolutions or turns of the encoder, you can no longer identify your absolute location simply by looking at the number. This limitation is akin to wrapping the trip odometer in your car - if you exceed the highest digit, you no longer know exactly how far you’ve driven just by looking at the number. For example, if your odometer displays “999”, you may assume that you’ve driven exactly 999 miles. However, if you don’t have a “thousands” digit on your trip odometer (which is common in some older cars), it's possible that you could’ve traveled 1999 miles, or 2999 miles, or 3999 miles and so on. Relative encoders don’t have this limitation as the servo drive simply continues incrementing and counting the position in reference to "home". Since most applications require multiple revolutions of the motor (in many cases, hundreds or thousands of revolutions), incremental encoders are more cost-effective options. While I cannot comment on every servo out there, I can discuss the products Teknic manufactures (the ClearPath motors which Neo7CNC demonstrates in this video). All ClearPath motors use relative encoders. Once you home a ClearPath motor, the motor will know exactly where it is on your machine as long as you don’t remove bus power. Additionally, Teknic sells a logic power back-up hub that you can use with the fractional horsepower, DC-input ClearPath motors to keep the encoder and DSP alive in case of bus power loss. If you use this logic power back-up feature, you will not have to home your system more than once unless you lose bus power AND logic power back-up (this feature is similar to how some absolute encoders work with a battery backup function). If you’re interested, you can learn more about this logic power back-up feature here: ua-cam.com/video/mALi3_QqyHk/v-deo.html Regarding your other question, you are not required to use proximity sensors with ClearPath motors, but you’re not precluded from using them either. ClearPath has a built-in hardstop homing routine, but if you prefer to use sensors, you could wire them into your CNC controller. I hope this information helps clear things up. If you have follow up questions please feel free to contact us directly through support@teknic.com. Best regards, Brendan F. - Teknic Servo Systems Engineer
You could, you'd just need to make sure you size it right. I went with the NEMA34 because there were a few unknowns as far as how the friction and belt tension would play into the movement. Thanks for watching
Such a nice interdisciplinary project! But it brings tears to my eye to see a 250-300 bucks servo used for something as simple as a chop saw stop :D
Nice project David.
Your channel is very inspiring to a budding home CNCer!
Keep up the excellent work mate
Hi, can you help me with the arduino code? i want to make a similar project, but in Brazil we dont have all the parts you used, i want to use a stepper motor, arduino Uno, keypad 16x16 and 2x16 lcd... with endstops... can you tell me if the code is just change the pins ? or the servo you used is diferent then pulse dir of steper?
Wonderful work Mr. Burrell, congratulations. Question: What kind o limit switch/home switch did you use for the homing of this project?
Thanks! The ClearPath servo is capable of setting home once it hits a hard stop. When the system initializes, it drives the carriage slowly until it contacts the very beginning of the actuator. That action sets the home position. Thanks for watching and commenting.
Love what you have done here. Is there a way to make it as metric instead of imperial. I am very new to Arduino but this would be awesome to have in our workshop???
There is a conversion in the arduino code where you can convert it to metric.
Your project is good.
very cool project David !
Thank you Marcel!
I did a prototype table saw fence. I made the mistake of using belt drive. I will change to a screw drive. Will use either an Arduino or RaspberryPi.
This belt is steel reinforced so I'm hoping it stays true. Thanks for the comment and for watching.
What video tool do you use to produce your video?
Don't servos with encoders always know where they are?
Hi MySchizo Buddy,
Neo7CNC asked Teknic to chime in on this question since this video pertains to ClearPath specifically. You asked a similar question on a Teknic video as well, so I have posted my response on both videos. To help other viewers, I've copied your question (and my response) from the Teknic video below:
ua-cam.com/video/-gigcf7ZzAQ/v-deo.html&lc=z23bgldwgxesgxjtbacdp43bv0jilo1th3blon2qaftw03c010c
_"There is a confusion about homing. Some youtubers say because of the encoder in clearpath servos you don't need homing on cnc machines. The encoder always knows where it is. While others say that if you turn off and on the cnc machine then you do need to home the machine. What about proximity switches? Do cnc machines need them with clearpath servos?"_
These are good questions, but some that require a longer response and additional background, so I apologize in advance for the long post.
Generally speaking, most encoders are categorized into one of two types: absolute encoders or relative encoders (also commonly known as “incremental” encoders). At a high level, the two types serve the same function (they provide position and velocity information back to the servo drive), although there are some notable differences.
Absolute encoders provide unique positional information throughout the entire range of the encoders’ travel. These encoders don't usually require homing because you can “read” the position at any time and know where you are (although you still need to correlate a specific absolute position to a specific location on the machine). Please note that we further differentiate absolute encoders by the number of “turns” they can experience before they are no longer “Absolute” because the encoder’s position wraps (more on this later). You can identify the two types as “single-turn” or “multi-turn” encoders.
On the other hand, a relative/incremental encoder needs to be "calibrated" or "homed" initially. An incremental encoder outputs electrical "pulses" as it rotates, and it's the servo drive's responsibility to monitor and count these pulses to keep track of how far the encoder has traveled. In order to translate this distance traveled into an absolute location on your machine, the servo drive needs a starting reference point (or "home" location). I.e. the incremental encoder is telling you how many counts away from "home" the system has traveled.
So, since an absolute encoder doesn't generally need to be homed, you might wonder why anyone would use an incremental encoder. While there are a number of cost and performance benefits to incremental encoders, absolute encoders can only register their absolute location within a finite number of revolutions. If your application exceeds the number of revolutions or turns of the encoder, you can no longer identify your absolute location simply by looking at the number.
This limitation is akin to wrapping the trip odometer in your car - if you exceed the highest digit, you no longer know exactly how far you’ve driven just by looking at the number. For example, if your odometer displays “999”, you may assume that you’ve driven exactly 999 miles. However, if you don’t have a “thousands” digit on your trip odometer (which is common in some older cars), it's possible that you could’ve traveled 1999 miles, or 2999 miles, or 3999 miles and so on. Relative encoders don’t have this limitation as the servo drive simply continues incrementing and counting the position in reference to "home". Since most applications require multiple revolutions of the motor (in many cases, hundreds or thousands of revolutions), incremental encoders are more cost-effective options.
While I cannot comment on every servo out there, I can discuss the products Teknic manufactures (the ClearPath motors which Neo7CNC demonstrates in this video). All ClearPath motors use relative encoders. Once you home a ClearPath motor, the motor will know exactly where it is on your machine as long as you don’t remove bus power.
Additionally, Teknic sells a logic power back-up hub that you can use with the fractional horsepower, DC-input ClearPath motors to keep the encoder and DSP alive in case of bus power loss. If you use this logic power back-up feature, you will not have to home your system more than once unless you lose bus power AND logic power back-up (this feature is similar to how some absolute encoders work with a battery backup function). If you’re interested, you can learn more about this logic power back-up feature here: ua-cam.com/video/mALi3_QqyHk/v-deo.html
Regarding your other question, you are not required to use proximity sensors with ClearPath motors, but you’re not precluded from using them either. ClearPath has a built-in hardstop homing routine, but if you prefer to use sensors, you could wire them into your CNC controller.
I hope this information helps clear things up. If you have follow up questions please feel free to contact us directly through support@teknic.com.
Best regards,
Brendan F. - Teknic Servo Systems Engineer
Why not a Nema 23 Clearpath?
You could, you'd just need to make sure you size it right. I went with the NEMA34 because there were a few unknowns as far as how the friction and belt tension would play into the movement. Thanks for watching