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Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
A lot of people have asked for a Step/dir to Analog board so people can run MACH3 and still use their Analog Amplifiers. Well i've finally made one.
Its Viper tune compatible and should have the features to do the job. It has a differential +- 10 volt differential analog output, current feedback input and enable output.
The loop time is much faster now and programmable up to 4000 samples /sec.
I am testing it on a AMC 80volt analog amp but I would like to have a few people test them on some larger amps on big mills.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
I bought a board from CNC4PC that does this, used for spindle control, with PWM.... What do you expect to sell yours for?
Thanks,
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Your only about a day late for my situation. I ended up building a simple PWM to 0-10V analogue board for my AMC 100A40 spindle drive.
Being that I use Viper drives already on XYZ axis, your new product would of fit in nicely with the AMC spindle drive.
How much are you selling them for, as my analogue board is a temporary fix until I find something better.
With the mill having been down for a couple weeks already, work has backed up considerably, and if my little board fails, I for sure will be calling you. Just don't go crazy on pricing. LOL
35 to 60 bucks is what I'm looking at if I go with what's out there by the likes of Homan Designs and CNC4PC.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
Larken
A lot of people have asked for a Step/dir to Analog board so people can run MACH3 and still use their Analog Amplifiers.
I am testing it on a AMC 80volt analog amp
But how will I be able to use my A-M-C drives that do not close the PID loop? I cannot close it to Mach.
Or does this board close an encoder loop?
Al.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
I bought a board from CNC4PC that does this, used for spindle control, with PWM....
Thanks,
This isn't for the spindle drive, its for the axis servo drive.
Quote:
Originally Posted by
Al_The_Man
But how will I be able to use my A-M-C drives that do not close the PID loop? I cannot close it to Mach.
Or does this board close an encoder loop?
Al.
Yes, it closes the loop and turns the analog drive into a closed loop step/dir drive, so the motor is locked waiting for step pulses to move it. You connect the encoder to the Step2linear board and tune the PID using a serial cable and vipertune.
(There was a board years ago called the pixie that did the same )
Al, do most drives supply a current monitor output, so i can sense load ? Is there a standard ?
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
This isn't for the spindle drive, its for the axis servo drive.
That depends. Some Mach break out boards, like the one I use, don't have a spindle control port, . So to get around that, I use the A axis step and dir pins and convert them from PWM to a analogue voltage.
It works well and as soon as you have a manual for your board, I will look into it.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
Larken
Al, do most drives supply a current monitor output, so i can sense load ? Is there a standard ?
I don't think there is a standard, for e.g. on AMC 1v out can represent a current (amp) value depending on switch setting the value also varies for each model model.
Al.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Sir,
Are you saying your interface will not work, if "Open Loop"; no encoder?
Thanks,
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
jeffserv
Sir,
Are you saying your interface will not work, if "Open Loop"; no encoder?
Thanks,
How do you run a servo open loop for CNC application??
Al.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Can this be used as a VFD control... no encoder feedback, Spindle Speed control? That is what I am asking... Maybe it cannot...
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
jeffserv
Can this be used as a VFD control... no encoder feedback, Spindle Speed control? That is what I am asking... Maybe it cannot...
No Jeff, its not for VFDs it for servo amplifiers that control a servo motor for the x,y,z, axis.
A VFD has a 0-10 volt input, but its too slow an input to control the motor in servo mode. The vfd has its own accel and decel settings.
An Analog servo amp has + and - 10 volt differential input and has very fast responce to send fwd and reverse power to the motor to hold high speed position.
A servo drive can be used to control a spindle in closed loop with an encoder, but its tricky because the spindle has a lot of mass and you can't suddenly change its speed or you may blow the drive. So s/w like Mach that could shut off while the spindle is running fast, could accidently stop sending step pulses to the drive, then the spinning mass of the motor generates a huge back emf. So its not recommended without a fail safe spindle controller.
So this thread isn't about spindles at this time, its just for servo controls
Quote:
Originally Posted by G59
I for sure will be calling you. Just don't go crazy on pricing. LOL
Its listed on my viperservo.com site. (look for the ad here with the snake)
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
Al_The_Man
I don't think there is a standard, for e.g. on AMC 1v out can represent a current (amp) value depending on switch setting the value also varies for each model.
Al.
I'm getting some feedback from customers drives and these MTS automation drives have a + - 10 volt output on the current monitor.
Input/Output Interface: Analog Signals
Velocity Command Input -- Differential input 0 to ±10 Vdc (15 Vdc Max)
Auxiliary Input --- Differential input 0 to ±10 Vdc (15 Vdc Max)
Velocity Output --- Select 1.25, 2.07, 3.71, or 4.54 volts per 1000 rpm
Current Output ---- ±10 volts = ± Peak Current
The AMC drive i have is a is a 25A8 , it has 2 current output lines.
CURRENT MONITOR
Current Monitor. Analog output signal proportional to the actual current output. Scaling is 4.4 A/V. Measure relative to signal ground.
CURR REF OUT
Measures the command signal to the internal current-loop. This pin has a maximum output of ±7.25 V when the drive outputs maximum peak current.
Measure relative to signal ground
Al, are you familiar with the CURR REF OUT and what it does ?
Larry
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
This is what I have on P1-9 pin.
I have never monitored it.
Al.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Hi,
The mill is a lagun 3v model and comes with linear encoder that were used by the heidenhain tnc155. This controller is damaged and I just can't see spending money to fix it. I'm able to move the 3 axis manually as well as modify the speed of the machine and can conclude that the drives and motors are working well. I would like to simply replace the controller with a computer and Mach3 and your board would come in handy.
Drives: EL.GE AZE-CC4Q with 0+/-10V input
Motors: isoflux 4.4Nm Torque...3 of them
Do you think i can use the linear scales on the machine to connect to your step2linear board?
As Mach 3 does not run closed loop, does this mean that your new board will be able to compensate or detect for positional errors?
Tuning is done thru a 9pin or 25pin serial? can a usb to serial cable be used?
Thx for the help...and let me know as soon as the step2linear are ready...i want to try!
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
ech2o2
Hi,
The mill is a lagun 3v model and comes with linear encoder that were used by the heidenhain tnc155. This controller is damaged and I just can't see spending money to fix it. I'm able to move the 3 axis manually as well as modify the speed of the machine and can conclude that the drives and motors are working well. I would like to simply replace the controller with a computer and Mach3 and your board would come in handy.
Drives: EL.GE AZE-CC4Q with 0+/-10V input
Motors: isoflux 4.4Nm Torque...3 of them
Do you think i can use the linear scales on the machine to connect to your step2linear board?
As Mach 3 does not run closed loop, does this mean that your new board will be able to compensate or detect for positional errors?
Tuning is done thru a 9pin or 25pin serial? can a usb to serial cable be used?
Thx for the help...and let me know as soon as the step2linear are ready...i want to try!
- If you can get quadrature outputs from the linear scale then the board can read them. As long as there is no or very little backlash, the scale should work.
-Mach3 just outputs the Step/Dir count, which is the exact position it expects the machine to be at, in real time. The Step2lin and the drive take care to make sure the motor is at that position.
-Tuning can be done thru a USB port if you have a USB - serial converter. I don't put a USB on my drives because they are too sensitive to noise (which servo systems love to generate)
-I should have it ready in a week or two. I'm working on the current sense inputs. I'm using a differential opamp and it looks like it will be able to connect to most amps with no modifications. Some amps output differential and some single ended current monitoring. For the single ended, you just ground the minus input.
Larry K
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
But how will I be able to use my A-M-C drives that do not close the PID loop? I cannot close it to Mach.
Or does this board close an encoder loop?
Al.
yeah
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Here is the actual board with the connections. The encoder connections are the same as my other viper drives (see v200 manual) .
I hope to have a full PDF for the Step2Lin soon. I will be adding to Vipertune to add data-logging, current display, 56k baud and other stuff.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
I still say, this can be used for a spindle motor provided you have an encoder and the unit, is between breakout board and AMC drive.
I will have to buy it and see what gives. Now all I need is a spare spindle motor................LOL.
The advantage would also be, possible reversing of the spindle, and maybe even Rigid Tapping, as this board would be able to give negative voltage.
I know Larken you don't think it would work, but in theory, it should.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
G59
I still say, this can be used for a spindle motor provided you have an encoder and the unit, is between breakout board and AMC drive.
I will have to buy it and see what gives. Now all I need is a spare spindle motor................LOL.
The advantage would also be, possible reversing of the spindle, and maybe even Rigid Tapping, as this board would be able to give negative voltage.
I know Larken you don't think it would work, but in theory, it should.
No, i didn't say it wouldn't work, its just hard on the drive if the step pulses stop when the spindle is running full out.
It Will work, but you may need a drive 2 x the rated motor current and voltage.
Larry
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Aaaaaah, Yes, now I understand.
But not too worry. As I said, my spindle is driven by PWM (step/Dir) from the 4th Axis terminal. I convert that PWM signal to an analogue voltage and then I feed that into 100A40 AMC drive. 10 Hp motor 3000 rpm and no problems yet. Drive is cool to the touch even after a full day of work.
Also, their is no issue whatsoever when the voltage goes from 10 volts to 0Volts. All it does is trigger the braking circuit of the drive. It works very well. The spindle stops within 1 second from 3000rpm. I think you have something here that is potentially more then you originally designed. For myself it would be the possibility of reversing the spindle without using relays and getting rid of my home made DAC.
Let us know when your manual and boards are available. I will buy one just to see what can be done.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
G59, What resolution is the encoder and what is the max rpm you would run on the spindle ?
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
BEI, 500 ppr x 2500 RPM maximum motor speed. So 20883 pulses per second at 2500rpm.
Technically a 250 ppr encoder would also do.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
I got it working and it works good.
Here is a video running a servo with a pulley on it running with a AMC drive.
https://www.youtube.com/watch?v=6yHG...ature=youtu.be
(excuse my voice, i sound like Stewie from Family guy, lol , it was late and i was excited)
I'm cycling the motor with the Exercise mode withing the drive.
The KP was set to 1000 with KP set to 300. You can see when i change the KD to 400, it gets unstable until i change it back to 1000
I have more to finish before releasing the drive, but i have a cnc router to finish and ship in the next week, so it won't be long after that to send them out.
Larry
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Hi Larry,
Would it work open loop or you think that the pwm "translation" to +/-10V will not be precise enough? You mentioned very little backlash to none...from your experience, what will be the magic number? If I need to change my encoders, would you recommend staying with linear encoders or switch to rotary? Do you have a good supplier to suggest for encoders? Thanks
Eric
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
ech2o2
Hi Larry,
Would it work open loop or you think that the pwm "translation" to +/-10V will not be precise enough? You mentioned very little backlash to none...from your experience, what will be the magic number? If I need to change my encoders, would you recommend staying with linear encoders or switch to rotary? Do you have a good supplier to suggest for encoders? Thanks
Eric
Eric, you have to run closed loop with an encoder, open loop would be totally useless. The USDIGITAL E5 or E6 series is the best one to get for the money. be sure to get differential outputs, and usually 1000 line is good.
The Step2Lin will be ready to ship at the end of the week . So i will send you a message about shipping.
One thing i added was a input to sense that there is power at the amplifier. It needed this to be safe, because if you turned the amp power off while the system was holding, then moved the motor, when you turned to power to the amp back on the motor would jump back violently since the encoder was still keeping the position.
So i have a opto-isolated input that will take up to 10 volts. You can just use a voltage divider off your main power that puts out 10 volts @ about 5 ma. Then when the step2lin sees the main power go off and come back on, it clears the encoder count and does a soft pwm startup.
On all my new boards, i've switched from the older 18F2331 to a 16bit DSPIC. My new PID loop is a bit improved from the older one, and i now have the Ki working much better. The sampling time is variable from 500-4000 samples per second with the Ki fixed at 1000. This makes the Ki not get unstable at high sampling rates and much more useful.
Larry
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
I'm adding some setup commands to the firmware to let you setup the analog amps easier. You will be able to set the DAC to output a test voltage so you can adjust the gain pot on the analog drive. I'm doing tests on different motors and voltages and see if the amp gain is too high, then the Step2lin barely uses the resolution of the DAC to control the motor, its better to use more resolution and have the amp gain less.
Certain higher sampling times seem to make more audible noise in the motor, so im trying different opamp bandwidth changes to suppress some of this. When the switching freq of the amp is only 20khz, high sampling times can modulate out as noise.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Hello again,
I found some information on my linear encoders. Do you think those will be compatible with your card? Thanks.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Those appear to be Heidenhain style which are typically 11µa sine wave, I'm guessing you will need the typical 5v square wave type. unless you can find a way to square them up, Heidenhain make add on units that will do this.
Al.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
It looks like the scale should be useable, but you will need a little comparator and driver circuit down at the linear scale. Since the step2lin has a 4x decoder, we can try it first by just squaring up the basic resolution. Here is a little circuit that should (might) work.
I'm not sure what those photosensors output, (maybe Al knows) but i'm assuming that if you put a 1K resistor in series, you should see the 7-16 uA peak-peak appear across it as a voltage. The LM393 comparator neg inputs go to an adjustable pot to let you find the center voltage of the peak-peak swing. The 1meg resistor is optional and works to create a "snapover" hysterisis to reduce jitter at the center point. The 26C32 is a differential line driver to drive the twisted pair cable (which i highly recommend on any encoder)
You can make the circuit on a small perfboard (go to addison electronics in montreal ) The circuit should be connected down close to the linear scale and is powered by the +5volts at the step2lin down the cable.
Larry
EDIT: I forgot to add a 1K pullup resistor on the output of each 393. (They are open collector)
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Thanks! That looks relatively simple and I think I already have some 393 at home!
I also found this on internet. The circuit is interesting since it amplifies the signal too. The 4069 hex inverter I found at Digikey has 14 pins and 6 comparators...so one chip. I was thinking of building two of them to generate A & B signals and maybe a third one for the index signal. I have no clue if this would work or not but it is relatively easy and cheap to try...What do you think?
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Eric, i don't think that circuit is for encoders scales at all. It requires a fair amount of voltage from the incoming circuit, because thats where it gets its power. (the scale puts out a tiny voltage)
And Its AC coupled so it couldn't work with very low speeds, and also there is no differential output. (seriously, don't waste your time building it )
Larry
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Hello! Thanks for the input! You are right about the Heidenhain scale putting out very little amps...11uA. I ll get started on your suggestion and keep you updated. Thanks again!
Eric
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
have a look at TI web site they have a program on there call web bench it for doing circuits they have a encoder bit on it so you can work out what's required for a circuit to run a encoder
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Hi
Congratulations! I noticed on Viperservo.com that your step2linear cards were ready. I ordered 3 of them! I will let you know how it turns out! Thanks for all the help. Eric
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
All Boards have been shipped. I will have the PDF ready in a few days.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Larry, do you have any kind of manual put together yet?
Al.
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Here is the manual with connection diagrams and powersupply. Its not yet finished, and but i will finish it soon. At least this should let you hook it up.
The current version of Vipertune will work with it, but i will upload a new version in a few days.
To download the manual, right click the View Manual link and hit Save Link_as
Step2Linear, ViperServo
Larry
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Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Hello,
Here are some questions following my very first try...
1-Can a usb to serial converter be used to communicate with the step2linear card via vipertune?
2-I have 15.4V at the step2linear card and it is giving me a 3beep error: low voltage input? is that normal? or is it because i did not use the low voltage to the drive option?
3-I think there is an error on the diagram for the power supply suggested in the manual. The polarity of the condenser should be reverse since the common is higher potential than the negative out of the bridge rectifier.
4-I quickly get a encoder trip alarm. It' s not clear to me how the step2linear reacts...does it stop working until the error is corrected or it will keep working anyway and it just warning you of a problem? If the card "stops working" how do we externally reset without powering it off?
5- My drive has only one input called UREF and a common, it is not clear to me how I can use the separate plus / minus signal coming from the step2linear card? Do you have an idea?
5- In the same idea, can I assume that the the small circuit you suggested to square up my sine waves from my Heidenhain linear encoders is working since i did not get a encoder fail warning? I do not have an oscilloscope and I am not sure how to verify if my circuit really works...
Thanks
Eric
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1 Attachment(s)
Re: Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module
Quote:
Originally Posted by
ech2o2
Hello,
Here are some questions following my very first try...
1-Can a usb to serial converter be used to communicate with the step2linear card via vipertune?
2-I have 15.4V at the step2linear card and it is giving me a 3beep error: low voltage input? is that normal? or is it because i did not use the low voltage to the drive option?
3-I think there is an error on the diagram for the power supply suggested in the manual. The polarity of the condenser should be reverse since the common is higher potential than the negative out of the bridge rectifier.
4-I quickly get a encoder trip alarm. It' s not clear to me how the step2linear reacts...does it stop working until the error is corrected or it will keep working anyway and it just warning you of a problem? If the card "stops working" how do we externally reset without powering it off?
5- My drive has only one input called UREF and a common, it is not clear to me how I can use the separate plus / minus signal coming from the step2linear card? Do you have an idea?
5- In the same idea, can I assume that the the small circuit you suggested to square up my sine waves from my Heidenhain linear encoders is working since i did not get a encoder fail warning? I do not have an oscilloscope and I am not sure how to verify if my circuit really works...
Thanks
Eric
1) Yes a USB to Serial converter does work. the ones that come with a disk allow you to set the baudrate.
2) Its the lowvoltage input that triggers the alarm. (It doesn't read its own powersupply voltage)
3) yes you are right, i'll fix that.
4)you need to get the vipertune working to be able to see if the encoder is working. Bringing the "lowvoltage" to zero will reset the step2lin.
5)Either of the analog Refouts has a full +10 to -10 volt swing. One is just the inverted version of the other to drive a differential amp input.
6)Once you get vipertune connected, you will be able to whether you can read the encoder. You can also run it as single ended if you pull down the unused input with a 2K res.
Ive attached a basic connection circuit. Here you can just connect the lowvoltage inputs to the powersupply. (Use the 2pin connector for this since you can disconnect it to reset the drive.) You don't have to connect the current sense inputs as they are only used to display current in vipertune.