Closed Loop Stepper Motors for CNC machines

[Music] everybody Bob here and welcome to another making stuff video today I'm going to be talking about stepper motors mainly it's going to be closed loop stepper motors but first let me show you an open-loop stepper motor anybody that has messed with 3d printing or Hobby C&C probably knows what this is this is just your regular old stepper motor it's open-loop you've got the wires coming off of the coils of the motor and then that's it now these motors will work great for 3d printing and Hobby CNC stuff like that but the main drawback to these motors is that if they lose a step for any reason or say you reach the limit of your machine there's just no way the motor can't can communicate back to your computer or your controller to tell it hey there's a problem I can't go any further or hey I tried to move ten steps but I only move five so that's the main difference is that these open-loop motors cannot communicate back with the controller now this is a closed-loop stepper motor here and I've got a link to this in the description of the video so check that out and the main difference is it has this encoder here on the back of the motor and that's what this extra cable is for this allows the motor to communicate with the controller so it can tell it that hey I can't go any further or you know I've missed the step what should I do so that's where this comes in this is the hybrid servo controller now these closed-loop motors are also known as hybrid stepper motors this is a controller and it's a little bit different from an open-loop controller because it will take this signal that comes in off this extra cable and it will it will process the information so if the controller says go ten steps and the motor only goes nine it knows hey this motor needs to go another step and it's gonna tell it hey you need to go one more step now if you reach the end of your machine like you know you're at the end of your x-axis and you the computers telling it to keep going that direction and it can't it will only try so long to move steps and it knows that it's missing these steps and it will alarm out and that's what this little extra signal is right here see there's an alarm and then there's also a pending but the alarm will it'll trigger an alarm and when it goes to an alarm state you can set these pins and go high or low and you can hook those up to your CNC software kind of like an emergency stop switch so that if one of these controllers errors out or it alarms out it'll pause the process until that problem can be fixed now depending all that does is when the computer says tells the controller to move a step the motor moves a step and then it communicates back hey I move that step you told me to that pinning will go low or high depending on the state of that communication so however this is programmed you know if you say move a step it'll go high when it moves a step and it's confirmed then the pin will go low so that's not really all that useful for seeing see applications that I know of but the alarm is very useful no another advantage of these closed-loop motors is that they run cooler and the reason they were in coolers because they they they use less amperage and that's because the amperage is controlled by these controllers now there's the your usual dip switch settings here for how many pulses per revolution and that can be set here with the dip switches just like an open-loop controller but it also controls the amperage these motors run a whole lot cooler and they'll run faster than an open-loop motor because anybody that set up one of these controllers for an open-loop knows that there's an amperage setting that you have to dial in and once you set it to that setting I mean it just always uses that many amps no matter what so if this motors just sitting idle it's still if it's energized it's still using those amps and that's why these get a lot hotter than these motors here and another advantage of these controllers is this one will run on AC voltage or DC voltage so if you've got a switching power supply you can hook it up to this and run this motor or you can just use a transformer and step down your house current as long as it's between 18 and 70 volts AC or 24 and a hundred volts DC it's going to power this motor and it's going to it's going to do all of the controlling for you now yes this thing can be probably can be reprogrammed but out of the box it does a very good job and I've been playing with this one motor quite a bit and I seen I've not found anything that I've needed to go into and reprogram it now that that can be done with a computer you can reprogram this and you can see here there's this little jack here it kind of looks like a foam cord and you have to buy a separate cable and then that plugs into your computer and you can download the software for this and then you can reprogram it and some of the things you can reprogram are if this switches on these signals are normally open or normally closed I think you can do some Diagnostics you can watch certain things as the motors running but I can't do that right now because I ordered the cable but it's gonna be about a month before it gets here so I really don't have any way of hooking this up to my computer to show that to you guys and I really haven't been able to do anything because I can't hook it up to the computer and I ran the software but it won't do anything if it can't talk to the controller that's the first thing when it boots up it'll try to find the controller and if it can't find the controller it won't go on any further so maybe I can be some more I can search some more that in a future video if you guys want to see that let me know in the comments alright so I've got this thing all hooked up here on the bench and I'm going to show you a few things about it and the first thing we need to do is get a temperature reading and we can see it's 71 point one degrees so that's going to be our starting temperature and that's pretty much the room temperature right now so now I'm going to power this on and this power supply will send 33 volts at about 375 milliamp s' to the controller and the motor now this power supply has a 2 amp limit and I believe the motor and controller have a 9 amp peak so this isn't able to sin the amperage this system is capable of handling so let me do this I'm going to turn it back off and I'm going to move the vice grips this way and then turn it back on now this isn't NEMA 34 motor this motor is huge I actually bought way too much of a motor and this is the only way I can do this is to hook something up to the motor that I can get enough leverage to get it to slip it's just got so much torque now what I'm going to do is I've got this all powered up I'm going to show you what happens when you when something forces the motor to move out of the position it should be so what I'm gonna do is I'm gonna push down on this and then the controller is going to know exactly how far this motor turn that it shouldn't have then it's going to tell the motor how many steps to go to go back to the position so that this pair of vice grips is exactly in the same orientation and I did put a little piece of paper towel folded it over on here because I don't want them mark up the shaft of this motor with these vice grips so here we go I'm gonna push it down and you can see and I'm gonna let go so the controller told the motor hey you need to go back so many steps and it'll do it the same way so if I go this way and it this is it's actually kind of hard to keep it from going but there we go so now it tells it it knows which direction the motor goes and it tells it to go back you know you knows how far to go back to get it to where it needs to be and another thing once you the amps on here this is what I was talking about how the motor controls the amperage of everything or the controller controls the amperage so when I push it down okay see it's trying to move back so it's sending energy to the motor to move it back you can see the amperage has jumped up to 1.1 amps but as soon as I let go it goes back down to that 365 range there so that's just some of the advantages that's where having a motor like this with the closed loop where it communicates to controller it's just so advantageous is it can it can tell when it misses a step and it knows what to do to correct it ok so now I have unplugged the encoder from the controller so the motor is no longer talking to the controller let's power it on and see what happens we've got the round the 360 milliamps still being drawn but I'm gonna move the vice grips and you can see it's missing steps and nothing's happening and as it's missing steps you can see the amperage doesn't change either because the motor and the controller are no longer talking to each other so that's what happens when the encoder is not connected to controller that just shows you how this closed-loop system works we've broken that loop and now it's open so there's no communication going on so this is just a regular stepper motor at this point alright so now let's try and make this thing alarm out I still have the encoder disconnected so it is not making a connection and I have my multimeter here and I'm just going to take a reading here on the alarm pins and you can see that they are open and when the terminals touch it'll beep and it goes to zero so you can see here when I hit these nothing happens so it means that the alarm pins are normally open now what I'm going to do is I'm going to power on the controller and I'm just going to put 5 volts to the pulse pin a couple of times and you'll see that the motor will try to move the vise-grips here and then it will stop and then I'm gonna keep telling it to move by sending it pulses and you'll see that the controller will alarm out so here we go seeing that tried to step and I'm tilt I'm still telling it to go there we go so now it has gone into an alarm phase you can see this LEDs blinking red that tells it that hey this controller is gone to an alarm mode and now let's take the reading on the alarm pins you can see those pins are now closed so that would be very beneficial if something bad happens between this motor and this controller it will tell the the CNC machine to stop so that you're not sitting here moving your your torch if it's a CNC machine or your router then bumping into things and and breaking things and to continue to run it's very advantageous to have that so that it can tell your machine to stop now that's something that you don't get with those normal open-loop motors so that there's another advantage of this right here alright so here's another way the machine can go into that air state and that is if it goes too far out of step so I showed you earlier if it missed steps it would go into an error state so here I'm going to force it if you warned about a quarter of a turn it's going to go into an error mode just like it did before so here I'm pushing it there we go it just went into air mode you can see the motors dead and we've gone into that error state right there all right so let's do our final temperature reading it has been on for about half an hour and it's 73 degrees Fahrenheit so it went up a couple of degrees so that's not bad I know that's not a really good test I'd want to put it under a load for a while that would be a much better test but I do know that these closed-loop motors do run much cooler than the open loops and really you know this wasn't that good of a test but you know for half an hour at 365 milliamps I'm sure an open-loop motor would be a lot warmer than just a couple of degrees all right so I've got kind of a dilemma here I ordered this motor because I was thinking about upgrading the motors on the CNC plasma machine to closed-loop and when I ordered this I was like hey I'll go up to the NEMA 34 which is what this motor is and I'll upgrade to a bigger motor well I didn't realize just how big of a motor this was and let me walk over here to the CNC plasma machine and I will hold this motor up next to one of the ones that I used before which is a NIEM of 23 and to show you the difference so yeah that's a pretty big step remoter and I really don't know what I'm gonna do with it that's my problem is I ordered one of these just so I could play with it and see what all I needed to do to upgrade my CNC machine to a closed-loop system but I don't think I'm going to be using this motor is just huge and there wouldn't be really any way to upgrade that plasma machine with this motor without having to build a new motor plates put different pulleys on there it's just not worth it plus the weight this thing weighs a lot it probably weighs about as much as four or five NEMA 23 motors now this one is a NEMA 34 so that's my dilemma I've got one stepper motor but I want to do something with it I've got an idea of what to do but I want to hear from you guys leave a comment and let me know if you had one big stepper motor what would you build with it I'd be interested to see that so any idea and no matter how crazy it is I want to hear about it leave that down there in the comments below and who knows maybe we'll be actually building that crazy project alright so I've got a link to these motors and the controllers in the description of the video so go there and check those out if you're interested in getting yourself some closed-loop stepper motors and if you've had any good or bad experiences with these motors let us know in the comments of the video and I hope you liked the video if you did please give me that big thumbs up and if you're not a subscriber please consider subscribing and ring that bell so you don't miss any upcoming making stuff videos and thanks for watching [Music]

Channel: Making Stuff

Views: 177,109

Keywords: CNC Stepper Motor, Hybrid Stepper Motor, Closed Loop, Closed Loop Stepper Motor, Open Loop, Open Loop stepper Motor, CNC Stepper Motors, CNC Servos, motor, motor controller, stepper controller

Id: SoRdEAm1auk

Length: 17min 0sec (1020 seconds)

Published: Mon Mar 04 2019