Looking for Testers for my new "Step2Linear" (Step/Dir to analog ) module

[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. 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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[jeffserv]

I bought a board from CNC4PC that does this, used for spindle control, with PWM.... What do you expect to sell yours for?

Thanks,

[G59]

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.

[Al_The_Man]

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.

[Larken]

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.

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 ?

[G59]

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.

[Al_The_Man]

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.
Al.

[jeffserv]

Sir,

Are you saying your interface will not work, if "Open Loop"; no encoder?


Thanks,

[Al_The_Man]

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.

[jeffserv]

Can this be used as a VFD control... no encoder feedback, Spindle Speed control? That is what I am asking... Maybe it cannot...

[Larken]

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

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)

[Larken]

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

[Al_The_Man]

This is what I have on P1-9 pin.
I have never monitored it.
Al.

[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!

[Larken]

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

[Larken]

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.

[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.

[Larken]

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

[G59]

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.

[Larken]

G59, What resolution is the encoder and what is the max rpm you would run on the spindle ?