[Guy69]

hello Matt
during my test, I did not generate my signal by software, but using a dedicated signal generator providing all the required current, I am pretty sure.

(and by the way, schematic of 540 published by Mariss does not buffer DB25 output)

Thanks
Guy

[keebler303]

Do you have an oscilloscope? I would try connecting a scope to the step input to see if your optos are working properly. You could also just get rid of your circuit altogether and connect the signal generator output directly to the step input. Also you might want to make sure that your signal generator is good on the current. I have an older one and anything above about 100 Hz gets clipped if there is any little load on the output. If you have a nicer one it shouldn't be an issue. The ones I've used at school had an output current of around 1A.

So take everything you can out of the equation to isolate the problem. Do you have another drive and motor you could test to narrow down the problem?

Good Luck
Matt

[Guy69]

Matt, you seem to have sleeping issues :-) what time is it at your place?

back to the point, yes I have a scope and signal looks great both at the input and output of the Optos. Perfect squares.
I was more worried either by mini gecko (or the ground connections) or by my motor.
Next week-end I will check with my 2nd mini gecko, and I have decided to buy another motor. I 'll let you know
Guy

[Mariss Freimanis]

My mind was AWOL when I said to use a buffer. All you are interested in is seeing a clean signal on the collector of the HCPL-2531, 0V and 3.3V. If you have a function generator, use it to test the drive. Set it to 'squarewave' and the amplitude to 0V and 3.3V.

Mariss

[Guy69]

Hi Mariss and others, here are some good news and 2 questions:

Good news is that with a new motor (a square one :-)) and a new power supply, I have good results with both torque and speed!
(I replaced my switched power supply salvaged from old server by a straight tranny, bridge and 2 big capacitors and I have 40V DC with min 6A).

The 2 questions are:
1. The step signal needs to be >5 V (measured on scope with 1V/div, below 5V,motor stops). How far can I increase this level? Can I supply the HCPL2531 with 12V?
I am worried because HCPL2531 Datasheet says "5V absolute maximum" for detector Emitter-Base Reverse Voltage. And G251 manual says that STEP "can be driven with 3.3V or 5V logic"

2. I am confused because stepper motor doc says "200 steps per revolution", and I see that I actually need 2000 steps to rotate 1 rev. Does G251 systematically use microstepping = 1/10 full step?

Many thanks indeed!
Guy

[keebler303]

1. I think you may have an issue with current, not voltage. You might not have enough current to drive the opto reliably.

2. Yes they have a fixed resolution of 1/10 microstep.

Matt

[Mariss Freimanis]

If you are using Mach3, make sure you have set STEP to 'active high' in 'ports and pins' and 'pulse width' is set to '2uS' in 'motor tuning'. If you are using something else, make sure the STEP input is at 0VDC when you are sending no step pulses and when you are, make sure the pulse is at least 2uS wide during its logic '1' time.

If the HCPL-2531 LED current limit resistor is 200 Ohms, the G251 will work with step pulse voltages as low as 2.5V. Post a schematic of your STP/DIR interface so that I can check it.

Mariss

[Guy69]

hello MAtt & Mariss (et al)

1. my turn to have my mind AWOL: I thought I was feeding G251 (from my signal generator) with a 5 V signal, it was in fact -2.5 to +2.5.... 5 V peek to peek, but of course only 2.5V above zero... Done for that.
2. 10 microsteps: all right, thanks Matt. I will cope with that

3. as for Mariss question, I am not using Mach3: during my tests I had the signal generator directly connectet to G251. My plan (almost finished) is to pilot th G251 (thru my BOB) from a home made .Net app. I am currently struggling with C# to control timer intervals in microseconds, and this should be ok very soon. If interested I will post that.

MANY THANKS
Guy

[apollonono]

Hi,
Mariss Freimanis

I argue about the division of 1/60 and 1/64 about the most suitable number of partitions.
The number of the binaries and yen sexagesimal system have them and help some application.
The common ratio is included in "1,2,3,4,5,6,, 10,12,15,, 20,30,, 60 /60s" "1,2,, 4,, 8,, 16,, 32,64 /64" these.

kyoji

[Mariss Freimanis]

Kyoji,

I don't have a clue what you are talking about ("1,2,3,4,5,6,, 10,12,15,, 20,30,, 60 /60s" "1,2,, 4,, 8,, 16,, 32,64 /64"). Can you please explain?

Mariss

[Teyber12]

i think hes talking about how many you guys offer in packages?

[apollonono]

Hi　Mariss Freimanis
Sexagesimal system thinks us to be a convenient number about astronomy observation.
Because they include the common number, "1,2,3,4,5,6,, 10,12,15,, 20,30,, 60 /60s" "8,16,32,64 /64" they can express this which is 16 kinds in SW of 4 bits in all.
I have some argument topics as well as this.
Will you argue with me?
kyoji

[hndswthtshdws]

Spent the last few days reading the entire thread. I'm planning a 3 axis router and I dont think I'd settle for anything less than Gecko drives now, but I have one question.

I'm planning on using a dual leadscrew X axis so I will need 4 drivers. G540 is perfect except for one thing.....what if later on I decide I want a 4th axis? Is it possible to externally add a 5th driver to the G540 or should I build my own BOB? I think with more research I could build my own BOB but I wont if I dont have to.

[Mariss Freimanis]

The G540 is a package and all self-contained packages have limitations. In the G540 case it's 4 drives, no more and no less. I believe adding a 5th drive requires a 2nd parallel port anyway but I could be wrong.

The G250 drives inside the G540 are protected against most anything you can reasonably do to hurt them (miss-wired motors, motor cable wiring shorts, reversed power supply polarity, overvoltage, etc.). Outside the G540, the G250/G251 is pretty fragile just like G201 is. Mistreat it and it will die. Make no mistakes and it works forever.

Mariss

[hndswthtshdws]

Thanks for the quick response. Being a newbie I would feel more comfortable with a plug and play system but at the same time I would like the knowledge and experience of doing the wiring myself. Guess I'll have to ponder some more

[apollonono]

Hi,
Mariss Freimanis

I of the coil method when "is bipolar", argue about "uni-Paula".
As for the bipolar method, torque type, the excess voltage outbreak are the power supply voltage neighborhood low speed very much.
The uni-Paula method high speed low torque type, the excess voltage outbreak of the power supply voltage is the double neighborhood.
Actually the voltage of time when several hundredV have a short both methods together is detected.
Please watch next.
http://den-nekonoko.blog.so-net.ne.jp/2009-05-09
kyoji

[yngndrw]

Mariss: May I suggest looking into making a 6 axis version. Basically a G540 with 6 axes, two parallel port connections and many more inputs and outputs.

I'm not sure how many people would be interested in such a setup, but it then allows a range of options.

8 axes are already catered for by buying two G540s so there just seems to be a gap - Not many people would pay an extra $300 for a fifth axis.

[jalessi]

yngndrw

No need for two LPT ports.

The SmoothStepper is a 6 axis motion control device that connects to the USB port of a computer.

http://warp9td.com/

Just purchase the individual number of Gecko drives you need separately.

Jeff...

[yngndrw]

Jeff: While I agree that it can already be done with what's currently available, it would be nice to have a self-contained package which has it all. (In the same way that the G540 is.)

Most computers these days seem to not have any parallel ports, so if you're going to use a parallel port PCI card then you might as well get a dual port one. Also by using a PCI add-on card you save a lot of money compared to using a SmoothStepper.

A bit off topic here, but if anybody's interested in a PCI parallel port card which works with Mach 3 - I use this: http://www.sunix.com.tw/it/en/Produc..._id=34&sid=365
I think it was about £10-15 and is dual port.

If you are having trouble finding the address of one in Vista, here's how I found mine:
Device Manager > Multifunction Adaptors > PCI 4018A Multi-I/O Adaptor > Properties > Resources
On this tab, I used the first "I/O Range" entry which for me was AF00-AF07. I entered AF00 as the address in Mach 3.

[jalessi]

yngndrw,

Gecko is coming out with a new stepper drive with a USB interface in the very near future.

I doubt Gecko is going to invest in what you are asking for when the technology product life cycle is nearly over.

Jeff...