Well thats great news. I have been trying to figure out how they communicate because it isn't as clear for boards that aren't specifically for arduino. I have also been having trouble finding high voltage drivers. I have found 1 that supports 80V and it was $75 which is a bit high for this project. It looks like I would need a pin for direction, a PWM output to control speed, then another pin that sends step info. I think I have enough information at this point to select a stepper and microcontroller, now I just need to determine which driver and power supply will make it work.
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Practicality Of Arduino Controlled Precision Power Feed?
- Thread starter shooter123456
- Start date
Here is one, not the cheapest but I keep a few on the shelf.
http://www.ebay.com/itm/Wantai-Step...457981?hash=item417d8feabd:g:wCAAAOxyni9TFxFi
All of these take a 5V square wave step input, 50% duty cycle and a 5V binary direction input. None use PWM for speed. Speed is determined by the frequency of the step pulse train. Thus only requires 2 pins to operate.
http://www.ebay.com/itm/Wantai-Step...457981?hash=item417d8feabd:g:wCAAAOxyni9TFxFi
All of these take a 5V square wave step input, 50% duty cycle and a 5V binary direction input. None use PWM for speed. Speed is determined by the frequency of the step pulse train. Thus only requires 2 pins to operate.
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Yep, standard 5v TTL compatible signals. The other reason for using the driver is that you can't just feed in 36v or even 5v to hold the stepper in place. Steady state holding voltage is usually only a couple volts.
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I looked at those but the power supply, driver, and motor needed to make all that work made everything a bit too expensive.
Are the torque curves from the page you linked pretty accurate universally?
Looking at these components
Motor - http://www.ebay.com/itm/US-Ship-Nem...634897?hash=item35f78f5e91:g:1tcAAOSwyQtVmybn - $34
Driver - http://www.ebay.com/itm/TB6600-0-2-...285412?hash=item51d2850ae4:g:YYoAAOSwrklVekYh - $17
Power Supply - http://www.ebay.com/itm/AC110-220V-...hash=item568004ea32:m:m-Tt3_1c6P79IZt8SZqzWPw - $28
Arduino - http://www.ebay.com/itm/MEGA-2560-R...025121?hash=item4af69c6761:g:L7EAAOSwKtVWy2GU - $13
Screen - http://www.ebay.com/itm/4-3-5-7-TFT...hash=item1c53a37023:m:m_LgsCZ0JW3NbAeGCZZJmxQ - $32
Total - $124
If my math was correct, and 100 oz-in is enough torque for rapids, this set up would be capable of about 115 IPM. Any thoughts or input? I think at 75 ipm rapids I would be happy, anything more is gravy.
I think you could use those charts as a general guideline. Automation Direct gives you pretty accurate documentation. I have seen other charts that I would consider rather optimistic.
There are too many variables to really give you a coherent answer. You might wrap a string around the handwheel dial and use a spring scale to figure out how much torque is required to turn the lead screw.
I'm perfectly happy with 100 IPM on my machine and I have 32.5 inches of travel on my X axis. 200 IPM is frighteningly fast. So I would say 75 IPM on your machine would be plenty.
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Thanks for all of your help here. I have ordered most of the parts and I have a design sketched out and I think I have the circuit mostly designed at this point. I should start getting parts in the next week or two. I went with a 3.6" screen instead of the 4.3 because it was 1/3 the cost and ended up with a less expensive power supply because the one I selected originally was out of stock.
There are a few things I haven't completely figured out and i was wondering if you could assist at all.
I want to wire in an e-stop for the stepper that works with the same button that cuts the spindle power. I was thinking I could run a relay to the button that would take the mill power and the power supply AC lines. Hit the estop and AC to both the mills motor and the stepper power supply are both cut. Could this be done safely or is there a better way?
I also want to put in a switch that will turn the stepper off completely so I can turn the handle without resistance. Is the best way to do that to interrupt power from the supply to the driver? It would need a fairly beefy 48V DC switch but I found several that should be able to handle that. However, I read that cutting power to the steppers like that could damage them. If thats the case, is there another way to safely turn the stepper off?
That should work fine. It's the way I would do it. I would wire it so the E-stop cuts power to the relay coil, but require another button push (control power ON) to energize it again, a standard 3 wire control. That way on a power fail it stays off, also just pulling the E-stop out won't energize the system. Just adds another layer of safety.
Ignore the OL contact in the drawing, not needed in this case.
When turned by hand, the motor becomes a generator and the power is fed back to the drive. Under extreme conditions, you could damage the drive by hand cranking. You need to break the connection between the motor and drive. This requires a 4 pole switch, could also be done with a 4 pole relay. But......You need to power down the drive before you break the connection so you don't damage the drive. The drive can be powered down under any condition, no problem there.
I like that way of running the E-stop. What is the button called that holds itself in as long as power is running through it? Do I just need to buy an estop button thats already wired that way?
As to breaking the connection between the motor and the driver, is it safe to put a switch between the driver and power supply and another 4 pole switch between the drive and the motor? Then to return to manual, flip the switch to the drive to power it down then flip the switch to the motor to break the connection? When turning it back on, would I power the drive or reconnect the motor first?
It's called a ''maintained contact button'' True E-stop switches are Normally Closed (NC) and push to open. Many are twist to release (recommended). They are mechanically held in position, not electrically. A relay can be held electrically, M1 in the drawing above is a relay, and one of the contacts is used to hold the power to the coil. This is called a ''seal in'' contact.
An example of an E-stop switch:
https://www.automationdirect.com/ad...ttons_Illuminated_-a-_Non-Illuminated/GCX1131
A switch between the power supply and the drive is perfectly acceptable in all cases. When powering up, always connect the motor to the drive first then power up the drive.
I have all the parts and I have been working on getting it all together. Think I may have broken some stuff already. The parts I am using are:
Driver - http://www.ebay.com/itm/351424285412
Power Supply - http://www.ebay.com/itm/351769808694
Stepper - http://www.ebay.com/itm/231786634897
I had the stepper hooked up to the driver in bipolar parrallel, with the A to A+ and A bar to A- and same with B. Then DC - on the driver to DC - on the power supply and DC + on driver to DC + on the power supply. Then wired the pulse + to an arduino output button and pulse - to arduino ground. Then same with direction. I set the power supply to 120V AC, set the driver to 3A, and full steps. I got it running like this for a few minutes. When I pressed a button, the motor would start stepping. As a ramped up the speed, there was a flash, a pop, and the supply conked out. I opened it up and there was a blown fuse in it. I ordered a better power supply here:
https://www.amazon.com/gp/product/B0113JHSRO/ref=od_aui_detailpages00?ie=UTF8&psc=1
And when hooked up with the marked + and -, there is no activity from the power supply. I got a DC output of 1.05V. When I disconnected the stepper and controller, then reversed it, DC - to + and vise versa, I get activity from the power supply, but nothing from the driver. Did the first power supply blowing also blow the driver? Does anything I did sound incorrect?
Driver - http://www.ebay.com/itm/351424285412
Power Supply - http://www.ebay.com/itm/351769808694
Stepper - http://www.ebay.com/itm/231786634897
I had the stepper hooked up to the driver in bipolar parrallel, with the A to A+ and A bar to A- and same with B. Then DC - on the driver to DC - on the power supply and DC + on driver to DC + on the power supply. Then wired the pulse + to an arduino output button and pulse - to arduino ground. Then same with direction. I set the power supply to 120V AC, set the driver to 3A, and full steps. I got it running like this for a few minutes. When I pressed a button, the motor would start stepping. As a ramped up the speed, there was a flash, a pop, and the supply conked out. I opened it up and there was a blown fuse in it. I ordered a better power supply here:
https://www.amazon.com/gp/product/B0113JHSRO/ref=od_aui_detailpages00?ie=UTF8&psc=1
And when hooked up with the marked + and -, there is no activity from the power supply. I got a DC output of 1.05V. When I disconnected the stepper and controller, then reversed it, DC - to + and vise versa, I get activity from the power supply, but nothing from the driver. Did the first power supply blowing also blow the driver? Does anything I did sound incorrect?