Setting ADTECH servos with Eding CNC software steps/AppUnit

I'm having trouble calculating the right steps/AppUnit for the servo motors im using...

Can anyone demonstrate how to calculate the correct settings so the motors move the correct distance ?

my setup consists of the following:

· ADTECH servos - http://www.adtechen.com/products/ACH-09075BC%28750W%29-Middle-Inertia-Servo-Motor.html



· 3.2:1 belt reduction - CNCRouterparts pro rack and pinion drive - http://www.cncrouterparts.com/pro-rack-and-pinion-drive-nema-34-p-226.html



· 35 Tooth Pinion and MOD1 Rack

any help would be very much appreciated

Bloody hell Derick do you realise with 35T and 3.2:1 you have 34mm pitch and with 2000Rpm motors you'll be getting in excess of 68M/min rapids.!!! . . . Tread careful mate the bloody gantry will flying off the end in blink of eye. . .Lol

Ok well you have 2500 count Encoders which will be quadrature so x4 gives 10,000 pulse per rev.
Then workout your Pitch which is 35 x Pi = 109.599mm per rev / 3.2(ratio)=34.361mm per rev

Now Calculation is 10,000 / 34.361 = 291.026 pulses per mm.

Hope you have a nice fast motion control card because you'll need nearly 300Khz to get full RPM from those motors.

Yeah I will have to tame the beast pal. Nearly had one misshap when messing about with the speeds on the X with one motor disengaged and not slaved, I ramped the speed up a little and I capped myself!!

So if I enter that information I should get the correct movement when I enter movement in the MDI? For example: X100 F300 I should get 100mm travel at a feed rate of 300 correct?

Quote:

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Originally Posted by D-man

So if I enter that information I should get the correct movement when I enter movement in the MDI? For example: X100 F300 I should get 100mm travel at a feed rate of 300 correct?

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Yep should work.! . . . But don't hold me to it. . Lol

Champion I will give it a bash pal cheers

Dean, I will be able to turn those rapids down tho correct?

Quote:

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Originally Posted by D-man

Dean, I will be able to turn those rapids down tho correct?

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Yes just set velocity to what you feel happy with.!! . . Thou ideally you would have calculated the ratio better to make full use of the motors potential and give better resolution rather than wasting motors potential. To be honest with 6:1 ratio you'd have got away with 3000rpm 400w motors.

Actually I've just thought and I think EdingCNC is limited to 125Khz frequency. In which case you won't get the full 2000rpm from those motors with 2500ppr encoders. You'll only get 750rpm unless you use electronic gearing using the drives, if they have that feature.

For the full 2000Rpm you'll need a frequency of 333khz.

I think your right yeah I saw that in the settings... So will that affect the calculations?

What cpu card are you using and how are you handling positioning feedback from the servos?

The board I'm using is this one http://www.edingcnc.com/products.php?productid=55

to be honest I'm not sure about the positioning I just know that there are two wires going into the inputs... At the moment I thought the encoder handled that

I take it that the encoder is connected to the servo amp then and that you are giving the amp step and direction pulses from the cpu card and the amp is handling the positioning control? I was just wondering because i didnt think that the eding cpu card took encoder inputs. I have the cpu 5b card for my next machine if I ever get it finished!

I think so. I'm new to servos and was told to put what wires I have into the inputs :/ I will get some pics when I get into the unit this morn

OK with those settings Dean i enter X100 F300 in the MDI and it moves 150.5mm so something is still off lol

Ok well first the Servo drives are dealing with the encoders closing the loop at the drives and all your doing is sending it Step & Dir signals(pulses).

I did make a mistake when I said you'd get +68 M/min because I forgot about the ratio so RPM would be 625rpm at the pinion giving Max Velocity of 34.5 x 625 = 21.5M/min Rapids. . . BUT that would be with full 2000 rpm from motors which you won't get if 125Khz frequency. You'll only get 750(rpm) /3.2(ratio) = 234(rpm) x 34.5(pitch)=8085mm/min.
So really your wasting plenty of the motors potential and machine rapid speeds.

Why those figure didn't work I think can only be because your ratio is not what you think it is.?

Thanks Dean I've managed to get the machine moving exactly 100mm, i'm over the moon! However the software would not disengage the motors when I tured the motors off so I'm having a little trouble with that at the moment. Oh the joys of CNC (Completely - No - Clue) lol

What do you mean when you turn the motors off? I didnt think that the software let go of the motors unless it had a failure or an emergency stop then you have to rehome the machine. I think that as soon as you press reset to start the machine the software has control.
You can check the amp enable output on the I/O screen to see the state of the I/O control.

What I mean is, if I press the 'off button' it asks would I like to turn the motors off. If I click yes nothing happens and the motors are still energised

Is the enable drives output still on?

When I put a tick in the box and save it.... It doesn't actually save it and the box is unchecked still

Oddly odd. If I get a chance I will check mine tonight and see what happens but I have a different cpu card from you. Might be best to email Bert and see what he says.

I will do that thanks. I had pondered on reinstalling the software so it was fresh incase something had happened in the download. Suppose it couldn't hurt

Like you say it woudnt hurt. Just make sure that the install drivers bit completes after the program install. I think it does need all its own stuff to work correctly. You could also try inverting the amp enable output just to see what happens.

Just tried mine and it does turn off the drives and also the tick in the I/O screen for enable goes off. I am using V4.01 of the software.
Probably best to email Bert and see what he says.

Ah I'm using 4.02. Wonder if I should use that version for now

It would be worth a try even if its just to see what happens. One thing I did notice was that after turning the drives off the button wont turn them back on. You have to press reset but that might be built into the software.

Yeah same on this version too

Have a go with V4.01. You don't have to uninstall the version you have.

Yeah I will pal,just finishing off some method statements for my company, worst job ever!

OK, version 4.01 still acts the same... couple questions if you don't mind?

1. The light on the board - When the drives are enabled is this light supposed to stay on?
2. The 5V to enable the drives - which inputs are these to go into? i originally had the in 16 and GND and it works but motors would still stay engaged if i disabled the motors with the software.

Sorry - the IO screen that button does stay checked. I got mixed up, its actually the amp enable that will not stay checked.

I have also soldered the bottom of the board as asked

Looking at the flyer for the cpu card it looks like you are using the watchdog output to enable the drives which appears to be correct for this cpu card. I think that the green led should be on when the drives are on because the watchdog signal will be ok. I think that the watchdog output signal is staying on even though you are turning the drives off but I don't know if this is correct for this cpu. I have had a quick look at the servo amp manual but im not sure if it the correct one for your motor. It says that the amp enable should be 12 or 24vdc switched from its own internal supply. Are you using the watchdog signal to switch a relay for the servo amp enable signal?

Yeah I'm using the watchdog to switch the signal to the drives.

The light switches on and off, however I wasn't sure which way it was supposed to be.

Do your motors continue to stay energised when you disable the motors within the software?

Yes they appear to switch off. If you are using a relay powered from the watchdog to switch the enable signal you can measure the voltage to the coil or see the coil switch. Looks like the info on the cpu says that the watchdog is green for ok and red for not so I presume that green is output signal and red no output signal. Can you check the voltage to the relay and see if it switches?

Yeah it's 5v

Does the relay switch on and off with the 5v watchdog signal? Does the 12 or 24 vdc supply for the servo amp enable signal switch on and of with the relay? I think we need to get the basics checked first.

Actually I think the drivers are hard wired..... See f I can get a pic of my installation up (using tap talk at the moment)

http://tapatalk.imageshack.com/v2/15...b485a0574b.jpg

http://tapatalk.imageshack.com/v2/15...54df14f42f.jpg

This is the way it's set up now. And it works but the motors do not switch

Right so does the solid state relay switch on and off? It should go on when you press reset and motor on on the software. Does it switch off when you press motor off? I'm just wondering if the watchdog should switch off when you press motor off. Do you have an emergency stop wired in yet? If so press reset then motor on and the relay should switch on, then hit the estop. I would think that this should shut off the watchdog output.

The voltage drops on the relay but still fails to disengage the relays. Should of stuck with steppers lol doing my head in this is haha