Need help for setting an AASD-30A servo drive as step-dir control

[Azalin]

Hi,

I have purchased 4 years ago an AASD-30A servo drive with its 1.8kw servo motor. Now I decided to use it as spindle motor on my CNC converted lathe. It is a simple 2 axis lathe.

I have the manual but I don't know which parameters I should change to use it in step-dir mode. Any info would be greatly appreciated.

Best,
Suat

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[CNCMAN172]

Look in your drive manual. The servo needs to be put in position mode, which accepts step and direction signals. Many drive can to position, speed, torque modes

[dazp1976]

Hi,

I have purchased 4 years ago an AASD-30A servo drive with its 1.8kw servo motor. Now I decided to use it as spindle motor on my CNC converted lathe. It is a simple 2 axis lathe.
I have the manual but I don't know which parameters I should change to use it in step-dir mode. Any info would be greatly appreciated.
Best,
Suat

This is one of the better manuals I've seen.
Clearer than the fasttobuy one:
Fairly straight forward to get it in position mode.
Are you clued up with the wiring too?.

https://www.google.com/url?sa=t&sour...PjhnIO8x-_w_5M

[Azalin]

Are you clued up with the wiring too?.

Hi,
I think I am. I found this in a youtube video. It's not much but looks like a good start.

[CNCMAN172]

Yup, you can set that servo drive up in position mode or speed mode. In speed mode you just need an analog voltage to control the speed and direction +-10V, position mode is also supported.

[dazp1976]

Hi,
I think I am. I found this in a youtube video. It's not much but looks like a good start.

This might be useful if using step/dir control for spindle.
I haven't looked at it myself but JAZZCNC is a reliable source for good information.

How to setup Chinese AASD Servo electronic gearing

[dazp1976]

Yup, you can set that servo drive up in position mode or speed mode. In speed mode you just need an analog voltage to control the speed and direction +-10V, position mode is also supported.

Problem is that unlike my servo there isn't a noticeable sigin input to switch direction when using analog.
However, reading the manual makes me think you could switch 'restrict cw' to run ccw and switch 'restrict ccw' to run cw. Then the analog connection is a straight forward 0v and +10v.

What you think?.
Anyhoo, op is asking about s/d use for spindle. I assume for tapping/threading.
I'd prob set up in hybrid position/speed mode and see how that goes.

[Azalin]

Hi again,
I got it working as a step-dir motor. CW and CCW works fine. However I have 2 problem now:

1- Servo spins at the quarter of the speed I want. I mean when I ender S1000 then the servo spins at 250 RPM. The encoder is a simple 2500 PPR incremental encoder so What Count Per Unit and Velocity should I enter in Mach4? I don't use electronic gearing or any kind of gearing. Everything is 1:1 ratio. Max motor speed is 3000.

2: Currently the servo is always enabled. Can I have it disabled when Mach4 is at idle state?

I forgot to mention that the BB I use is a cnc4pc M16 with PoKeys57E

Thank you all.

Here is the video of the first run:

[dazp1976]

Hi again,
I got it working as a step-dir motor. CW and CCW works fine. However I have 2 problem now:
1- Servo spins at the quarter of the speed I want. I mean when I ender S1000 then the servo spins at 250 RPM. The encoder is a simple 2500 PPR incremental encoder so What Count Per Unit and Velocity should I enter in Mach4? I don't use electronic gearing or any kind of gearing. Everything is 1:1 ratio. Max motor speed is 3000.
2: Currently the servo is always enabled. Can I have it disabled when Mach4 is at idle state?
I forgot to mention that the BB I use is a cnc4pc M16 with PoKeys57E
Thank you all.
Here is the video of the first run:

Can't remember how it works but possibly read somewhere 2500ppr could be per quarter segment of encoder, not full revolution. That means you'd need to multiply things by a factor of 4. That could poss explain it.

It was a while ago so check into ppr and calculations on Google search. Some decent info should crop up.

[Azalin]

I see people play with the parameter PN098 (electronic gearing). Most people use 20 for that parameter. I don't know why. Maybe run smoother? Anyway, I set that parameter to 20 as well.

In Mach4 I played with Counts Per Unit and Velocity. After some time my final values are CPU: 750 and Velocity: 2000. Now I have perfectly matched RPMs. I don't know this is the right way to achieve.

Here's my second video:

[CNCMAN172]

Keep in mind 2500 p/r is actually counted in quadrature mode so 10,000 p/r, hence why you are running at quarter speed

[joeavaerage]

Hi,
if you don't use electronic gearing, then you are in reality using 1:1 electronic gearing.

As has been posted yout encoder is 2500 lines or pulse per rev, so when combining the A and B channels in quadrature you get 10,000 count per rev.

Lets imagine you want to run your servo at max rpm, 3000rpm, then:
pulses (per minute) =3000 (rpm) x 10,000 (counts/per rev)
=30,000,000 pulses per minute OR 500kHz. This is the signal speed you require from the PoKeys, and I don't think the PoKeys can go that fast. Additionally
you'll need to use differential signalling of your CW/CCW or you'll never get to 500kHz. Best you can get single-ended is about 150kHz.

So if you want to reduce the signal rate down to something more manageable then you'll have to use electronic gearing of some description.

Craig

[Azalin]

Great info Craig. Thanks.

[joeavaerage]

Hi,
electronic gearing sounds quite confusing but it is in fact pretty straight forward and really REALLY useful.

Your servo has a natural encoder resolution of 10,000 counts per rev. In theory its resolution is 1/10000 of a rev or 2.16 arc.minutes.
That's pretty good, and highly desirable on an axis where you want very fine resolution, but it also means that your controller has to signal very fast
to get the servo to get to maximum speed.

It may well be that you do not require such fine resolution, or maybe your controller just cannot signal fast enough, or the electronics/wiring required to signal
that fast over that length is just too much. What can you do?

Thats where electronic gearing comes in.

Electronic gearing has two parameters, one is called the Denominator and the other is called the Numerator, and as the names suggest they are combined
to form a fraction. Lets say N=20 and D=100.

Lets say your controller issues 10,000 pulses, after going through the electronic gearing module:

10,000 x 20/100= 10,000 x 5
=50,000

So after going through the module the number of pulse seems to magically have increased and the servo will turn not just one revolution but five revolutions.
This is quite handy because now your controller only has to signal one fifth as fast to do the same job.

Note also that if N=D then the fraction is one, and the electronic gearing module is just 1:1 and has no effect.

If N=20 and D=100 the fraction is 1/5, but equally you could choose N=241 and D=1205 and the fraction is still 1/5. This means the choice of numbers is not unique.

You might ask why the manufacturer went to all this extra trouble to have this feature? Imagine you have an old machine that has a failed DC servo motor that had
and early model 512 line (2048 count) encoder and you want to replace it. If you were offered a servo with a 10,000 count encoder you could not use it in the same machine
wit the same control.....but if you use electronic gearing N=94, D=459 then 10,000 x 94/459=2047.9, so close enough that you could use it. Very convenient!
As soon as one manufacturer did it then they all had to in order to remain competitive.

All in all its a nice feature so you can tailor the resolution of the servo to your application. I would guess for instance that you don't need such fine resolution
for your spindle, particularly if it means you are going to struggle to signal the servo that fast. If you chose an electronic gear ratio of 10:1, that is N=10, D=100,
then to signal your servo to its max speed instead of 500kHz that I calculated in the previous post, but now you only need to signal at 50kHz, a much easier task.
That would mean that the resolution drops to 21.6 arc.min or 0.36 degree, which is probably good enough!

Craig

[dazp1976]

Hi,
electronic gearing sounds quite confusing but it is in fact pretty straight forward and really REALLY useful.

Your servo has a natural encoder resolution of 10,000 counts per rev. In theory its resolution is 1/10000 of a rev or 2.16 arc.minutes.
That's pretty good, and highly desirable on an axis where you want very fine resolution, but it also means that your controller has to signal very fast
to get the servo to get to maximum speed.

It may well be that you do not require such fine resolution, or maybe your controller just cannot signal fast enough, or the electronics/wiring required to signal
that fast over that length is just too much.
Craig

Well.
As a related question. (and maybe useful to others?).
My control board is high speed but can't do a differential connection, only open collector single ended.
So, I've been looking at these converter boards below.
I supposedly should be able to directly connect pnp to any lpt TTL port outputs on my UC300eth as open collect.
Use the converter to then output that as differential to the Servo and make use of the available encoder resolution.
Yes?.

https://www.aliexpress.com/item/3287...Adapt=Pc2Msite
Or
https://www.aliexpress.com/item/3301...Adapt=Pc2Msite

https://www.cnczone.com/forums/attac...d=480072&stc=1

[joeavaerage]

Hi,

My control board is high speed but can't do a differential connection, only open collector single ended.

Sorry to say the UC300ETh is not that fast, it's specs are 400kHz, so certainly very useful but not fast in the scheme of things. My ESS is 4MHz and that is still in the Hobby class. A Gallil is 22Mhz!

Single ended signaling is OK up to about 150kHz. If you wish to go higher that that then you'll need differential signaling. Some of those boards you linked to would work.
Note though that differential signaling is 5V output. When you hook up to the drive for differential signaling you bypass some of the current limit resistors and so if you
signalled at 24V you'd blow the opto couplers. In absence of the current limit resistors 5V is enough to drive the opto couplers at full speed.

I built my own breakout board and used AEC7272 differential line drive IC's, but the much more common and cheap 26LS31 ICs will do very well also. 26LS31's are a dollar or
so each, if you can be bothered making your own.

To be honest....'do you actually need high resolution on your spindle'. I mean what process or operation that is going to require a few arc.min positional resolution?
The only thing I can think of is maybe indexing a round shaft at 60 degree intervals to mill flats for a nut, or maybe rigid tapping, but even those operations would be perfectly
OK with 20 arc.min resolution.


I think your complicating something that is actually very simple.....and the complication will only delay the implementation and deployment of your servo, not to mention costing
yet more dollars! Did I recall you say you have had this servo for years without using it?

The servo manufacturer has included electronic gearing to enable you to simply and easily apply the servo to your application....just use it, and you can have your servo running today!.

Craig

[dazp1976]

Hi,

Sorry to say the UC300ETh is not that fast, it's specs are 400kHz, so certainly very useful but not fast in the scheme of things. My ESS is 4MHz and that is still in the Hobby class. A Gallil is 22Mhz!
'do you actually need high resolution on your spindle'.

I think your complicating something that is actually very simple.....and the complication will only delay the implementation and deployment of your servo, not to mention costing
yet more dollars! Did I recall you say you have had this servo for years without using it?
Craig

Forgot about the uc300eth limit. A new type may be coming from cncdrive in future.
I'm talking more about if/when I had one on an axis.
I'm using analog on the spindle. Maybe look later if I ever need to tap.
Yes. Haven't been well enough to use machine lately (a while) or finalise some bits of it.
Been fiddling with electronics side more lately to see what configs work and what doesn't.

[Azalin]

Hi again,

I'm trying to understand what I'm reading in the manual about enabling the servo. As I mentioned the machine is a lathe and I need the servo enabled only when a program is running.

So the parameter Pn003 will be set to 0 and the SigIn port will be connected to the control card and the card will feed that port with 5v or something?



Sorry if this is a stupid question. The manual is very confusing.

[CNCMAN172]

You use pin-6 to enable the drive. On most drivers you need to pull the servo-enable input low to activate the drive. Check your manual on pin-6

Russ

[dazp1976]

Hi again,
I'm trying to understand what I'm reading in the manual about enabling the servo. As I mentioned the machine is a lathe and I need the servo enabled only when a program is running.
So the parameter Pn003 will be set to 0 and the SigIn port will be connected to the control card and the card will feed that port with 5v or something?
Sorry if this is a stupid question. The manual is very confusing.

First off. The Servo controls run off 12v-24v psu.
5v to the port is no good. You'd need a 5v relay controlled by the card with the Servo port and appropriate power size attached to com/nc. Relay will then enable servo when control tells it to.

Sigin are low so the pins pull down to psu GND.

I would make life easy and just fit a manual switch somewhere and enable it when needed.

P6 > switch in > switch out > 12-24v psu GND. That's it.

On the wiring diagram can you see what looks like an = sign as you follow circuit from P9, with a long line on the top and a shorter line below it?. That is the symbol for the power supply. The long side is +, the short side is the - (GND) .

On my diagram P9 goes to the + side of the 12-24v psu.
Then the -(GND) side of psu goes to P6,7,21,8,10 via switches where needed.

If on yours P9 is 12-24v +ive & P10 is com (GND), these 2 may need parmanent connection to turn the actual control circuit on in the first place.
Not entirely sure on this so check it in manual.