Want to learn about industrial automation? Go here: www.realpars.com/individual-pricing Want to train your team in industrial automation? Go here: www.realpars.com/pricing-team
Thanks for the compliment and the suggestion, Jay! I will surely pass this on to our creator team. We do go into more depth in our course library bit.ly/30AVJaR Feel free to have a scroll through our courses, I'm sure it's of your interest. Happy learning!
Incremental are best in unpredictable motion/speed, long ways or/and high speed. Absolute in saw cutting machine, bending machine(the hidraulic piston), treading, drilling, or any repetitive work being mechanism or short(70cm) robotic arm with only one hemisphere of movement like human hand for safety reasons replacing workers at handpackaging cookies, wafers, bread, small packs in big one's, bags, lightbulbs, clocks, glasses, unpackaged items, cups, plates, saucepans, wine, handling freshly pressurized champagne wich sometimes explodes and injures the worker's hands.
As a Automation engineer, this channel is absolutely marvelous! Do not stop producing amazing content! p.s. looking forward for a video about OPC UA :)
What software do you use to make these awesome animated examples. I would like to use it to make quick project sample views for project meetings. Thanks!
Hi Jeremy, Thanks for your comment! Happy to hear that you like our animations! To be honest, I am not sure about this as this is done by our graphic and animation department.
For a three-bit absolute encoder, as shown in the example, the minimum measurement magnitude would be 1/8 of a full rotation (45 degrees). If they're so precise, how do they encode smaller increments? Or are their bit depth larger in real life?
A very resolute absolute encoder has 12 or more "tracks" which gives the device 12-bit resolution (1 bit per track). 2^12 = 4096 divisions/revolution. This level of resolution is provided optically by detecting light pulses produced by very small photodiodes, a precise mask disk and an LED light source. Up to 10,000 increment per revolution are now possible.
Thank you for your question. I have provided two links to help you learn more about encoders. www.encoder.com/article-what-is-an-encoder#:~:text=Simply%20put%2C%20an%20encoder%20is,count%2C%20speed%2C%20or%20direction. ua-cam.com/video/k2GQVJ4z0kM/v-deo.html Happy learning from REALPARS!
Hey. Thank you for a great explanation. I do not have much knowledge about sensors, and I m looking for some type of sensor for my project. My question is; we will drill using earth auger, and we want to count the rotation number. As I understood, I cannot use these types of encoders because I need to connect to the drill bit, and it completely will rotate, so I cannot connect these encoders to the bit and the drill itself. Should I search for magnetic encoders working with rings? In this way, I can place the magnetic ring on the rotational part, and I can count the rotation with an encoder that is close to the ring? Am I right? Thanks!
Thank you for your question. You have an interesting issue. If you're counting the rotation of a drill when it completes 360 degrees, you can use any electrical sensor that detects a marker on the rotating part, like the drill chuck or any other part that turns 360 degrees. You'll need to send this signal to a controller to utilize this rotational motion as needed. Happy learning!
False! The absolute definition cannot account for the position angles between output changes. The only thing it could do is assume position angle based on current input to the motor and last known RPM. What that design us doing is giving an output every 1/6 rotation it seems. However, if you were to add incremental pulses to the outter edge, you could know where the shaft is up to the resolution of the smallest gap between larger gaps. But if power is removed and restored it could only tell you which 1/6 its in and whether or not it is at an increment. But not which increment of that 1/6 it's at.
In a video i saw about my encoder , it did not require a power source. A womans hand turned the shaft and the led board lit up. I figured pretty simple setup. After receiving my encoder i hooked it to the led board and nothing happened. What am i missing ??? Im not an electronics wiz.
Thank you for your inquiry. In general, electronic devices necessitate power to facilitate the transmission and reception of information. This power can originate from an external source like a power supply or internal batteries. Some devices are even capable of generating their own power through rotation. For specific guidance on your encoder, I recommend reviewing the installation manual or reaching out to the vendor you obtained it from. Wishing you a productive learning experience with RealPars!
Thanks for your topic suggestion, I will happily pass this on to our course developers as a possible future video course. Thanks again for sharing and happy learning!
Thank you for your comment, Tomas! Regarding your question, I am actually not sure about that, as our animations are all created by our Graphic and Animation department.
The absolute and incremental definitions of a rotating shaft are not accurate. In your example it is only absolute in regard to a single rotation of a motor or shaft. It is highly unlikely that a motor or shaft would be installed on equipment and never operate outside of a single rotation. Anything beyond a single rotation would then be incremental. This could be otherwise on a linear motor or railway. I worked with programming and maintaining motion control stepper motors and equipment. My experience was all with glass scale optical encoders and magnetic switches. Glass scale linear and rotational indexing where black lines were printed on the scales. Great stuff as long as it is clean.
Stan, thank you for your comments. I have worked with dozens of stepper motor applications for turntables, positioning bars for lane deflection, and other applications that require less than one revolution of a motor shaft. For these applications, absolute encoders are essential, and they do report absolute position. I would contend that applications that require more than one revolution also benefit from absolute encoders, as position can be accurately determined by counting revolutions. But in this case, you are correct, that in the case of power failure, CPU failure, etc., the absolute encoder would be no more than a fancy incremental encoder.
I did not get it, can anyone can explain please. 5:39 how 111 code can precisely determine the degree. Since the video shows that 111 code is somewhere between 315 to 360 degrees. Or it is a mechanical counter like miles counter in an old car? In that case why do we need that laser system after all. Thanks.
The video shows a simplified version of an optical slotted disk absolute encoder with 3 bits of resolution. That is equivalent to 45 degrees. Actual encoders can have up to 28 independent light paths. 28-bit accuracy is equivalent to a resolution of 0.00000134 degrees. That would be a little tough to show in the video, so it was simplified to demonstrate the principle.
At work I wrote some software to use an incremental quadrature encoder to characterize the output of an absolute position magnetic encoder. Interesting to see how the particular placement of the magnet affects the absolute position encoder’s output
Hi Andrew, Thank you for your question. The inclusion of the feature you mentioned in the encoder's electronics could vary based on the manufacturer and its intended use. To gain accurate information, I recommend consulting the operator's and data manual specific to your encoder. Wishing you a fruitful learning experience with RealPars!
Yes, there are typically 2 "code tracks" that are slightly out of phase so that both position and direction can be detected. Some incremental encoders use two separate light sources (could be LED's, laser. etc) and two receivers to determine the position and direction of rotation.
I don't quite understand the absolute rotary encoder. For example , the disk start from 0 degree and it's 000 binary , for it to rotate until 001, it needs 360/8(binary digits/different pattern) = 45 degree, how can it knows where is the disk ? is it 23 deg ? is it 40 deg ? because the binary is still 000 , the pattern doesn't change
For an absolute encoder, as the encoder disk turns, the "pattern" that is sensed is unique for every position that can be sensed. The encoder in the video is only a 3-bit encoder, capable of detecting changes of 360/8 or 45 -degrees. So you are correct: between 0 and 45 degrees, the pattern does not change. However, an actual encoder, say a 15-bit encoder, is able to discern 360/32768 or 0.011 degrees of rotation. Each increment has a unique pattern, so the encoder always knows where it is relative to the 0-degree, or home position.
But how does the absolute encoder know the exact position? In the example that starts at 5:20 when the code is 011 it could be 150° or 170° or anything in between
My best guess is they can increase the number of bits (slots on the disk)... The example here was a 3 bit encoder... You may use 4 or even more bits to make it more precise of the angles?
Kelmat is correct. The video shows a simplified example. With an absolute encoder, there is a distinct bit pattern for every position, so that the position can precisely be known. Many absolute encoders utilize multiple disks for position determination and many are able to determine absolute position over up to 4096 increments/turn.
I knew something didn't 'add up' with the binary code and the degrees so I thought it may have been a simplified example. Then I confirmed by looking it up (en.wikipedia.org/wiki/Rotary_encoder) and sure enough, an interruptor disc with many more slots is listed in the picture above. If you ask me, there is something hypnotic about the arrangement of these slots in a rotational pattern. But anyhow, I scroll down here to see if anyone had the same question and here I am!
I think there is a mistake in this video. Please correct me if I am wrong. A CNC milling machine would typically use a rotary encoder located inside the stepper motors. A linear encoder is typically used in a digital readout (DRO) on a manual milling machine.
The use of linear or rotary encoders depends on the application, not on the "class" of the machine. in the video. a linear encoder is used with a CNC milling machine where the part is moved back and forth in a linear direction. If the machine were a CNC lathe, then a rotary type encoder would be used.
Nah bro, So basically, the servo motor needs a rotary encoder to feedback to the drive by default. A rotary encoder cannot see lost motion, such as backlash, but a linear encoder can, as it moves linearly along the axe. A linear encoder on a cnc machine is only there in order to achieve greater accuracy. With a stepper motor it is completely different to an ac servo, it doesn't require a rotary encoder, however you can add both a rotary and a linear encoder if you wish to achieve true closed loop control.
for absolute encoding, this article might be interesting: en.m.wikipedia.org/wiki/Gray_code by the way: when code is on a wheel, make sure it doesn't slip due to obstruction so a reset position might be s good idea ... on the other hand: using a stepper motor might be as good as the incremental measuring as long as rotation of the axis is not obstructed.
No, the encoder position is always a positive number. If you want to establish a zero-reference and track position by + (clockwise) or - (c0unter-clockwise) from that reference, you could do that by keeping a separate integer variable that you can program with a value that increments up or down based on encoder position. That is a lot of work, and i find using the encoder's raw position value to be the best to use.
Hi there, Thanks for your comment! That would make for a great future video course! I have gone ahead and passed this on to our course developers as a topic suggestion. Thanks for sharing and happy learning!
In a sense, you are correct. The bills are mechanically pulled through a microprocessor scanner one at a time, and based on how many times a beam of light is interrupted, the machine knows how many bills it pulled through. While this is technically not an incremental encoder, it works pretty much the same. As the bills go through the cash sorter, combinations of Ultraviolet (UV), Magnetic (MG), and Infrared (IR) are used for counterfeit detection and pattern recognition is used for detecting the denomination and orientation.
Not exactly. The index for an incremental encoder generates a pulse which allows the encoder to "home", such that an accurate "count" of position from the "home" position can be made. In an absolute encoder, each position has a unique pattern. The index pulse of an incremental encoder only provides a reference location given once for each revolution.
Hi there, We're glad you found RealPars videos useful; You can share our video as long as it remains unmodified, tagged and credited back to us. Unfortunately downloading our videos from UA-cam or RealPars platform and translating them goes against UA-cam and also RealPars copyright. Thanks for your understanding.
The PLC represented in the video is a Siemens S7-1500 series PLC. The lower-cost S7-1200 can be used to program all of the same examples shown in our videos as well.
If the incremental and absolute encoders have the same reference (zero) position, they should both give the same result provided they both have the same resolution. In practice, that does not happen. The incremental encoder has a zero position wherever the position is when the encoder is powered on. It simply indicates how many turns the shaft has made since it was first enabled. So while it is possible to approximate the action of an absolute encoder with an incremental encoder, this is not often done because there would need to be another function required to position the shaft to a precise zero position.
@@realpars By integrating a microprocessor and an external battery I designed a system that ensures that the incremental encoder position is kept in memory continuously. I converted it into a thesis and my thesis was accepted.
No. This would require changing out the device. The incremental and absolute encoder signals are very different in the way the position is determined. Absolute encoders use multiple light paths to determine an absolute position whereas an incremental encoder has one light signal that pulses each time a fractional movement of the rotating disk is detected.
Hi Yahai, Thanks for your comment! I will pass this on to our course developers as a topic suggestion. This would make for a great future course video. Happy learning!
So let's use the typical 1024 pulse per revolution shaft mounted encoder. That means each revolution of the motor send 1024 pulses to the motor controller, typically some kind of VFD or PLC which in turn controls the motor controller. Most applications are geared so that means we must take account the gear ratios between the motor and load. Let assume we are a 1:1 ratio and we are controlling rotational position scaled to units of degrees. It depends on the software used but in siemens motion control, you scale the units and define as rotational motion. This sets the units you use when setting acceleration or deceleration as degrees/sec/sec and position in degrees. You define the position of the movement in length units. Let's assume for simplicity we define 3600 length units per revolution of the motor, that means when I command the motor to move 3600 length units it will move the motor one revolution at whatever accelerating I defined. What the motor does depends on what type of movement you have chosen. There are several types of movements, ranging from absolute, relative, synchronization position and speed movements, gear in movements and other more complex movements. A simple position movement will be defined as either relative or absolute. A relative movement will move whatever length units you defined from its current position. An absolute move will move to that specific position. So let's say, our position is 3600 LU and we move relatively 10000 LU, the motor will move until the position is 13600 LU. An absolute move would have put the motor position at 10000 LU. So to sum up, motion control is counting the encoder pulses from the motor and correlating that to some rotational or linear travel through defining this in meaningful units and issuing commands to the drive based on these units.
An absolute encoder is designed such that the optical path through the encoder at any time indicates the absolute position of the encoder wheel, between 0 and 360 degrees rotation. An absolute encoder maintains its position information when power is removed from the encoder. An incremental encoder gives only a change in position from one measurement time period to the next. An incremental encoder may need to be homed (moved to a fixed reference point) to initialize absolute position measurements.
With an absolute encoder, there is a distinct bit pattern for every position, so that the position can precisely be known. Many absolute encoders utilize multiple disks for position determination and many are able to determine absolute position over up to 4096 increments/turn.
which software did you use for creating these videos. I really appreciate you have put a lot of effort into creating these videos, I wanted to create them in a similar fashion for my class seminars as well.
Hi there, Thanks for your kind comment, we appreciate such support! I am actually not sure about this as this is done by our Graphic and Animation department. Sorry about that!
Hey! Thanks for your comment, happy to hear that you are enjoying our content! I am actually not sure about this as this is done by our graphic and animation department.
Desde Colombia. la forma como explican cada tema es muy clara. me gusta mucho su calidad de multimedia. pareciera que tuviéramos los elementos en nuestras mismas manos.
I have a absolute type encoder which is gray code output may i replace it with Binary coded absolute encoder? If you know please help me Thanks in advance.
Yes. HOWEVER, gray code and binary are not the same number system, so you would need to modify your PLC code to replace the gray code to absolute position conversion with a binary code to absolute position conversion.
I really appreciate the video, content of video is quite enough to vive the idea of working of encoders. Can you please provide a video on "Heidenhain AK ERM 280" type encoders?
Want to learn about industrial automation? Go here: www.realpars.com/individual-pricing
Want to train your team in industrial automation? Go here: www.realpars.com/pricing-team
Another top quality video. I just wish you guys could go into more depth but I appreciate what you do put on here.
Thanks for the compliment and the suggestion, Jay!
I will surely pass this on to our creator team. We do go into more depth in our course library bit.ly/30AVJaR
Feel free to have a scroll through our courses, I'm sure it's of your interest.
Happy learning!
I actually learn something of great value with every video of yours that I view! Thanks, RealPars!
That is amazing, Bob! Thanks a lot for sharing.
Incremental are best in unpredictable motion/speed, long ways or/and high speed. Absolute in saw cutting machine, bending machine(the hidraulic piston), treading, drilling, or any repetitive work being mechanism or short(70cm) robotic arm with only one hemisphere of movement like human hand for safety reasons replacing workers at handpackaging cookies, wafers, bread, small packs in big one's, bags, lightbulbs, clocks, glasses, unpackaged items, cups, plates, saucepans, wine, handling freshly pressurized champagne wich sometimes explodes and injures the worker's hands.
As a Automation engineer, this channel is absolutely marvelous! Do not stop producing amazing content! p.s. looking forward for a video about OPC UA :)
Thanks a million for your support, Paul! Great to hear that you are enjoying our course videos so much. Happy learning!
It's really a great continent 👏
I really appreciate this content it has been of so much use to me.
That is amazing, Sheliza! Very happy to hear that!
What software do you use to make these awesome animated examples. I would like to use it to make quick project sample views for project meetings. Thanks!
Hi Jeremy,
Thanks for your comment! Happy to hear that you like our animations!
To be honest, I am not sure about this as this is done by our graphic and animation department.
For a three-bit absolute encoder, as shown in the example, the minimum measurement magnitude would be 1/8 of a full rotation (45 degrees). If they're so precise, how do they encode smaller increments? Or are their bit depth larger in real life?
A very resolute absolute encoder has 12 or more "tracks" which gives the device 12-bit resolution (1 bit per track). 2^12 = 4096 divisions/revolution. This level of resolution is provided optically by detecting light pulses produced by very small photodiodes, a precise mask disk and an LED light source. Up to 10,000 increment per revolution are now possible.
Thanks for the great content. Yes, more detailed videos would surely be much appreciated!
You are very welcome! Thanks for your feedback!
I really like the way you explain the components. It is clear to understand.😀
That is a great compliment, Djenny! Thanks for sharing that with us!
please give me a definition of the encoder?
Thank you for your question. I have provided two links to help you learn more about encoders.
www.encoder.com/article-what-is-an-encoder#:~:text=Simply%20put%2C%20an%20encoder%20is,count%2C%20speed%2C%20or%20direction.
ua-cam.com/video/k2GQVJ4z0kM/v-deo.html
Happy learning from REALPARS!
Excellent Explanation and teachings on Encoders with how to use it in specific application,
Thanks to team RealPars--- A Indian-- Engineering Student
Glad it was helpful!
I don't know what this is but this is fascinating
Hey. Thank you for a great explanation. I do not have much knowledge about sensors, and I m looking for some type of sensor for my project. My question is; we will drill using earth auger, and we want to count the rotation number. As I understood, I cannot use these types of encoders because I need to connect to the drill bit, and it completely will rotate, so I cannot connect these encoders to the bit and the drill itself. Should I search for magnetic encoders working with rings? In this way, I can place the magnetic ring on the rotational part, and I can count the rotation with an encoder that is close to the ring? Am I right?
Thanks!
Thank you for your question. You have an interesting issue. If you're counting the rotation of a drill when it completes 360 degrees, you can use any electrical sensor that detects a marker on the rotating part, like the drill chuck or any other part that turns 360 degrees. You'll need to send this signal to a controller to utilize this rotational motion as needed. Happy learning!
False! The absolute definition cannot account for the position angles between output changes. The only thing it could do is assume position angle based on current input to the motor and last known RPM. What that design us doing is giving an output every 1/6 rotation it seems.
However, if you were to add incremental pulses to the outter edge, you could know where the shaft is up to the resolution of the smallest gap between larger gaps. But if power is removed and restored it could only tell you which 1/6 its in and whether or not it is at an increment. But not which increment of that 1/6 it's at.
In a video i saw about my encoder , it did not require a power source. A womans hand turned the shaft and the led board lit up. I figured pretty simple setup. After receiving my encoder i hooked it to the led board and nothing happened. What am i missing ??? Im not an electronics wiz.
Thank you for your inquiry. In general, electronic devices necessitate power to facilitate the transmission and reception of information. This power can originate from an external source like a power supply or internal batteries. Some devices are even capable of generating their own power through rotation. For specific guidance on your encoder, I recommend reviewing the installation manual or reaching out to the vendor you obtained it from. Wishing you a productive learning experience with RealPars!
@@realpars theres no manual
Can you please help me to make a code for DMX512 stapper motor with encoder
Please help me
HOW TO ABSULUTE ENCODER ? WITH S7-300 SIEMENS THANKYOU
Thanks for your topic suggestion, I will happily pass this on to our course developers as a possible future video course.
Thanks again for sharing and happy learning!
My friend I want a brief video about safety relays
Thanks for the topic suggestion, Kahlil. I will definitely go ahead and forward this to our creator team. Happy learning!
A brief video on the uses and functions of slip rings. Thank You.
Which software do you use to draw/modelize that panel??
Thank you for your comment, Tomas! Regarding your question, I am actually not sure about that, as our animations are all created by our Graphic and Animation department.
Excellent presentation. I used to work on systems that employed these devices.
Thank you, Juan!
U r welcomed.
The absolute and incremental definitions of a rotating shaft are not accurate. In your example it is only absolute in regard to a single rotation of a motor or shaft. It is highly unlikely that a motor or shaft would be installed on equipment and never operate outside of a single rotation. Anything beyond a single rotation would then be incremental. This could be otherwise on a linear motor or railway. I worked with programming and maintaining motion control stepper motors and equipment. My experience was all with glass scale optical encoders and magnetic switches. Glass scale linear and rotational indexing where black lines were printed on the scales. Great stuff as long as it is clean.
Stan, thank you for your comments. I have worked with dozens of stepper motor applications for turntables, positioning bars for lane deflection, and other applications that require less than one revolution of a motor shaft. For these applications, absolute encoders are essential, and they do report absolute position. I would contend that applications that require more than one revolution also benefit from absolute encoders, as position can be accurately determined by counting revolutions. But in this case, you are correct, that in the case of power failure, CPU failure, etc., the absolute encoder would be no more than a fancy incremental encoder.
A binary encoder is unrealistic and impractical; a Gray scale is used in practice.
Great video explaining the difference between absolute and incremental! Thanks!
Glad you enjoyed it!
I did not get it, can anyone can explain please. 5:39 how 111 code can precisely determine the degree. Since the video shows that 111 code is somewhere between 315 to 360 degrees. Or it is a mechanical counter like miles counter in an old car? In that case why do we need that laser system after all. Thanks.
The video shows a simplified version of an optical slotted disk absolute encoder with 3 bits of resolution. That is equivalent to 45 degrees. Actual encoders can have up to 28 independent light paths. 28-bit accuracy is equivalent to a resolution of 0.00000134 degrees. That would be a little tough to show in the video, so it was simplified to demonstrate the principle.
At work I wrote some software to use an incremental quadrature encoder to characterize the output of an absolute position magnetic encoder. Interesting to see how the particular placement of the magnet affects the absolute position encoder’s output
Do optical encoders require debounce filtering?
Hi Andrew,
Thank you for your question. The inclusion of the feature you mentioned in the encoder's electronics could vary based on the manufacturer and its intended use. To gain accurate information, I recommend consulting the operator's and data manual specific to your encoder.
Wishing you a fruitful learning experience with RealPars!
RealPars "crew", would you please define "absolute position" for me? Thank You.
@Mohammad Reza, I appreciate Mohammad.
but Incremental encoders have 2 lasers to be able to sense direction
Yes, there are typically 2 "code tracks" that are slightly out of phase so that both position and direction can be detected. Some incremental encoders use two separate light sources (could be LED's, laser. etc) and two receivers to determine the position and direction of rotation.
Most encoders are in quadrature. 01-25-2020.
High quality content to person like me as beginner plc programmer
thinks for information it is very nice
Many thanks for your awesome videos. 👏👏Let's comment to support the channel. 👍
Thank you, Mehmet!
I don't quite understand the absolute rotary encoder. For example , the disk start from 0 degree and it's 000 binary , for it to rotate until 001, it needs 360/8(binary digits/different pattern) = 45 degree, how can it knows where is the disk ? is it 23 deg ? is it 40 deg ? because the binary is still 000 , the pattern doesn't change
For an absolute encoder, as the encoder disk turns, the "pattern" that is sensed is unique for every position that can be sensed. The encoder in the video is only a 3-bit encoder, capable of detecting changes of 360/8 or 45 -degrees. So you are correct: between 0 and 45 degrees, the pattern does not change. However, an actual encoder, say a 15-bit encoder, is able to discern 360/32768 or 0.011 degrees of rotation. Each increment has a unique pattern, so the encoder always knows where it is relative to the 0-degree, or home position.
@@realpars Ah I see. So a x bit encoder use x led arrays to detect and 2^x different patterns?
But how does the absolute encoder know the exact position? In the example that starts at 5:20 when the code is 011 it could be 150° or 170° or anything in between
My best guess is they can increase the number of bits (slots on the disk)... The example here was a 3 bit encoder... You may use 4 or even more bits to make it more precise of the angles?
@@sagelioneldsouza8230 i see, so doing some calculations you need at least 9 bits to get a 360° precision
@@Kelmat_ yess :) Glad we figured it out🥂 Thanks
Kelmat is correct. The video shows a simplified example. With an absolute encoder, there is a distinct bit pattern for every position, so that the position can precisely be known. Many absolute encoders utilize multiple disks for position determination and many are able to determine absolute position over up to 4096 increments/turn.
I knew something didn't 'add up' with the binary code and the degrees so I thought it may have been a simplified example. Then I confirmed by looking it up (en.wikipedia.org/wiki/Rotary_encoder) and sure enough, an interruptor disc with many more slots is listed in the picture above. If you ask me, there is something hypnotic about the arrangement of these slots in a rotational pattern. But anyhow, I scroll down here to see if anyone had the same question and here I am!
2021 watching thanks sir very helpful
Our pleasure, Bernard!
Wow...very clear explanation
Glad to hear that, Eko! Thanks for sharing
I think there is a mistake in this video. Please correct me if I am wrong. A CNC milling machine would typically use a rotary encoder located inside the stepper motors. A linear encoder is typically used in a digital readout (DRO) on a manual milling machine.
The use of linear or rotary encoders depends on the application, not on the "class" of the machine. in the video. a linear encoder is used with a CNC milling machine where the part is moved back and forth in a linear direction. If the machine were a CNC lathe, then a rotary type encoder would be used.
Nah bro,
So basically, the servo motor needs a rotary encoder to feedback to the drive by default.
A rotary encoder cannot see lost motion, such as backlash, but a linear encoder can, as it moves linearly along the axe.
A linear encoder on a cnc machine is only there in order to achieve greater accuracy.
With a stepper motor it is completely different to an ac servo, it doesn't require a rotary encoder, however you can add both a rotary and a linear encoder if you wish to achieve true closed loop control.
How does the incremental encoder know which direction it is moving/rotating?
It would only know by detection of the direction of rotation of the encoder drive shaft.
for absolute encoding, this article might be interesting:
en.m.wikipedia.org/wiki/Gray_code
by the way: when code is on a wheel, make sure it doesn't slip due to obstruction so a reset position might be s good idea ...
on the other hand: using a stepper motor might be as good as the incremental measuring as long as rotation of the axis is not obstructed.
Thanks for adding that!
Is there a way to preset a negative value?
No, the encoder position is always a positive number. If you want to establish a zero-reference and track position by + (clockwise) or - (c0unter-clockwise) from that reference, you could do that by keeping a separate integer variable that you can program with a value that increments up or down based on encoder position. That is a lot of work, and i find using the encoder's raw position value to be the best to use.
Nice video, please upload more part and technology of cnc machine
Thanks for your feedback and suggestion!
Can you please tell me how encoder works in hydraulic intensifier?
Hi there,
Thanks for your comment!
That would make for a great future video course! I have gone ahead and passed this on to our course developers as a topic suggestion.
Thanks for sharing and happy learning!
Your channel is really helpful and easy to understand Thank you 😊
That is amazing to hear! Thanks for sharing.
No body can not explain like this.
... Clear explain ....👏👍
Thank you so much!
Am I right? Incremental Encoder used in cash sorting machine for counting.
In a sense, you are correct. The bills are mechanically pulled through a microprocessor scanner one at a time, and based on how many times a beam of light is interrupted, the machine knows how many bills it pulled through. While this is technically not an incremental encoder, it works pretty much the same. As the bills go through the cash sorter, combinations of Ultraviolet (UV), Magnetic (MG), and Infrared (IR) are used for counterfeit detection and pattern recognition is used for detecting the denomination and orientation.
great video quality and clear explanations!
Thanks for your support, Andrea!
For the first time i found a good explanation.thank you so much
Happy to hear that, Hamza! Feel free to reach out if you have any questions.
An incremental encoder can also have an index channel as well, so in that sense can it not also be an "absolute" encoder?
Not exactly. The index for an incremental encoder generates a pulse which allows the encoder to "home", such that an accurate "count" of position from the "home" position can be made. In an absolute encoder, each position has a unique pattern. The index pulse of an incremental encoder only provides a reference location given once for each revolution.
Great explanation! I'm considering subscribing to your website so that I can learn more.
Awesome, thank you! Feel free to reach out if you have any questions about our course library or our subscriptions services.
Happy learning!
Great! Can i use your video and translate to vietnamese?
Pls answer for me.
Goodluck to you and thanks for your videos.
Hi there,
We're glad you found RealPars videos useful; You can share our video as long as it remains unmodified, tagged and credited back to us.
Unfortunately downloading our videos from UA-cam or RealPars platform and translating them goes against UA-cam and also RealPars copyright.
Thanks for your understanding.
RealPars You are the best. You explain very accessible. Good luck to you
Amazing to hear! Thanks for sharing.
Definitely one of the best promotional videos I've seen in a quite some time!
Glad you enjoyed it
What kind of PLC your are using in the course?
The PLC represented in the video is a Siemens S7-1500 series PLC. The lower-cost S7-1200 can be used to program all of the same examples shown in our videos as well.
Thank you very much for great explanation and very useful information.
Glad it was helpful!
Is it possible to have a design that will allow the incremental encoder to act like an absolute encoder?
If the incremental and absolute encoders have the same reference (zero) position, they should both give the same result provided they both have the same resolution. In practice, that does not happen. The incremental encoder has a zero position wherever the position is when the encoder is powered on. It simply indicates how many turns the shaft has made since it was first enabled. So while it is possible to approximate the action of an absolute encoder with an incremental encoder, this is not often done because there would need to be another function required to position the shaft to a precise zero position.
@@realpars By integrating a microprocessor and an external battery
I designed a system that ensures that the incremental encoder position is kept in memory continuously. I converted it into a thesis and my thesis was accepted.
Can we make incremental to absolute or vice versa....
No. This would require changing out the device. The incremental and absolute encoder signals are very different in the way the position is determined. Absolute encoders use multiple light paths to determine an absolute position whereas an incremental encoder has one light signal that pulses each time a fractional movement of the rotating disk is detected.
how can i control the distance by using the encoder and how can we calculate the impulse
Hi Yahai,
Thanks for your comment!
I will pass this on to our course developers as a topic suggestion. This would make for a great future course video.
Happy learning!
So let's use the typical 1024 pulse per revolution shaft mounted encoder. That means each revolution of the motor send 1024 pulses to the motor controller, typically some kind of VFD or PLC which in turn controls the motor controller. Most applications are geared so that means we must take account the gear ratios between the motor and load. Let assume we are a 1:1 ratio and we are controlling rotational position scaled to units of degrees. It depends on the software used but in siemens motion control, you scale the units and define as rotational motion. This sets the units you use when setting acceleration or deceleration as degrees/sec/sec and position in degrees. You define the position of the movement in length units. Let's assume for simplicity we define 3600 length units per revolution of the motor, that means when I command the motor to move 3600 length units it will move the motor one revolution at whatever accelerating I defined. What the motor does depends on what type of movement you have chosen. There are several types of movements, ranging from absolute, relative, synchronization position and speed movements, gear in movements and other more complex movements. A simple position movement will be defined as either relative or absolute. A relative movement will move whatever length units you defined from its current position. An absolute move will move to that specific position. So let's say, our position is 3600 LU and we move relatively 10000 LU, the motor will move until the position is 13600 LU. An absolute move would have put the motor position at 10000 LU.
So to sum up, motion control is counting the encoder pulses from the motor and correlating that to some rotational or linear travel through defining this in meaningful units and issuing commands to the drive based on these units.
What is the difference between an incremental encoder and a absolute encoder?
An absolute encoder is designed such that the optical path through the encoder at any time indicates the absolute position of the encoder wheel, between 0 and 360 degrees rotation. An absolute encoder maintains its position information when power is removed from the encoder.
An incremental encoder gives only a change in position from one measurement time period to the next. An incremental encoder may need to be homed (moved to a fixed reference point) to initialize absolute position measurements.
@@realpars thank you 🙏
Is there actually encoders that output binary? I thought Gray Code was what they used.
With an absolute encoder, there is a distinct bit pattern for every position, so that the position can precisely be known. Many absolute encoders utilize multiple disks for position determination and many are able to determine absolute position over up to 4096 increments/turn.
Yes you are correct.
Really, all your videos are amazing, ❤❤❤❤❤
Glad you like them! Thank you very much for your support
which software did you use for creating these videos. I really appreciate you have put a lot of effort into creating these videos, I wanted to create them in a similar fashion for my class seminars as well.
Hi there,
Thanks for your kind comment, we appreciate such support!
I am actually not sure about this as this is done by our Graphic and Animation department.
Sorry about that!
@@realpars oh thanks. Not a problem
done🍕
Thank you Realpars for the video.
Our pleasure, Amit!
Excellent explanation. Thanks 🙏🙏🙏🙏
Glad you liked it!
Excellent video
Thank you!
What application do you carry out the animations with?
Hi Gaston,
Thanks for your comment!
I am not sure about this as this is done by our graphic and animation department.
awesome explanation with visualization
Glad you liked it! Thank you for sharing
Realpars is doing a great things to learn students
Glad to hear that, Karthik! Thanks for your support.
I found this great and i will be waiting for more on electromechanics.Thanks.
That's great to hear, Bekir! Thanks a lot for sharing.
Thanks this is a very interesting matter
You are very welcome!
Excelent video! Great explanation! greetings from México!!
Thanks a lot, Zarek! Happy to hear that.
Thank You :)
You are very welcome!
That's why Gray code is vital.
How are
Please I need bdf book for Plc from realpars
Could you please a simple video explaining difference between simotion and sinamics
Hey!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
Love your videos. What software do you use to make your animations?
Hey!
Thanks for your comment, happy to hear that you are enjoying our content!
I am actually not sure about this as this is done by our graphic and animation department.
Desde Colombia. la forma como explican cada tema es muy clara. me gusta mucho su calidad de multimedia. pareciera que tuviéramos los elementos en nuestras mismas manos.
Muchas gracias, Cristian!
Thank you Real pars👍👍👍
You're very welcome!
Awesome!!!
Thank you!
wow it is good tuto
Thanks for giving wonderful knowledge
You are very welcome, Subham!
Really helpful thank u sir👍
You're very welcome!
bravo bravissimo signorino
Absolutely great! Big up
Thank you! Happy learning!
Thank you very much sir 🙏😊
You're more than welcome!
Good
Nice
Thank you!
Greatest channel on UA-cam
That's great to hear! Thanks for sharing and happy learning.
Thank you RealPars !!!
You are very welcome, Emmanuel!
Merci beaucoup
Our pleasure!
I have a absolute type encoder which is gray code output may i replace it with Binary coded absolute encoder? If you know please help me Thanks in advance.
Yes. HOWEVER, gray code and binary are not the same number system, so you would need to modify your PLC code to replace the gray code to absolute position conversion with a binary code to absolute position conversion.
@@realpars Thanks for your reply
Very useful 🤝
Glad to hear that!
Excellent realpars thanks alot
You are very welcome, Tariq!
Thank you for clarification on transducers and encoders
You are very welcome! Happy learning!
Awesome and happy new year sir
Thanks a lot, Siva!
The RealPars team wishes you a splendid new year as well!
Thank you for sharing. Nice video!
You are very welcome! Happy learning!
Thank you for all you are doing for techs out in the field
You are very welcome, John! We appreciate your support!
Thanks 👍
You're very welcome, Emilios!
I really appreciate the video, content of video is quite enough to vive the idea of working of encoders. Can you please provide a video on "Heidenhain AK ERM 280" type encoders?
Hi Vikrant!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
THANK YOU SIR
You're very welcome!