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Offline Katoh

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Digispeed not working
« on: March 20, 2012, 02:01:04 AM »
Colleagues
While on my lathe retrofit I started many moons ago, I have finally had time to put some electrical components together, and start testing circuitry. My first test was the Digispeed DC03 Homman Design, I have wired up as per schematics and literature available but for some reason I can not get the Relays to respond.
I must be missing something here.
I am using the Homman MB02 V6 Bob and have set the jumpers according to the schematic, and wiring as per schematic. Refer http://www.homanndesigns.com/pdfs/EN012_V1.pdf.
The board and the digispeed are both powered.
Does someone have these running and could they advise what settings they use in mach and how they have wired them.
Thanks
Katoh
Cheers
Katoh
Re: Digispeed not working
« Reply #1 on: March 20, 2012, 04:09:45 AM »
Hi Katoh,

The version of the engineering note you re looking at is version 1, the current version is V3. It shows a different setting as line 17 is used by the Chargepump.

http://www.homanndesigns.com/pdfs/EN012_V3.pdf

Cheers,

Peter.
----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com

Offline otpco

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Re: Digispeed not working
« Reply #2 on: March 20, 2012, 06:17:06 PM »
Man I hope this works ! its sending us nuts here in the capital !

Offline Katoh

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Re: Digispeed not working
« Reply #3 on: March 20, 2012, 06:17:50 PM »
Hi peter
Sorry for the late response, I see on the updated schematic there is no Reverse wire to the VFD. How will the M3 and M4 work?
Thanks
Katoh
Cheers
Katoh

Offline Katoh

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Re: Digispeed not working
« Reply #4 on: March 20, 2012, 06:23:46 PM »
Man I hope this works ! its sending us nuts here in the capital !

Yes well its my lathe, your mill and my new mill that ride on the balance of getting this going. Peter doesn't have the DC06 any more and the one on my router works flawlessly, but he assured me the DC03 was a lot better.

Katoh
Cheers
Katoh

Offline otpco

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Re: Digispeed not working
« Reply #5 on: March 20, 2012, 06:44:25 PM »
Just ordered some spare parts for us all . with a few of us up here using the same boards it might be handy .Thinking of traping peter and keeping him here for a few days . Lets build a trap !!!
Re: Digispeed not working
« Reply #6 on: March 20, 2012, 07:03:21 PM »
...there is no Reverse wire to the VFD. How will the M3 and M4 work?
I use a TECO FM-50 VFD on my lathe, and you can set it to either run forward by energizing FWD and reverse by energizing REV, or select forward/reverse by toggling REV (I use this scheme).  It's a parameter I set from the VFD's front panel.  Maybe your VFD has a similar setup.

Randy
Re: Digispeed not working
« Reply #7 on: March 20, 2012, 09:03:18 PM »
Hi,

No need to set a trap. I'm here.

Ok to answer a few things.

1.Step Pulse Control DC-06 - This DigiSpeed takes a step pulse train and converts it to a control voltage, where the voltage is set by the frequency of the step pulses.   Basically the pluses are used in a charge pump. An analogy of this is filling up a bucket that has a leak using a cups of water. You can maintain any level in the bucket by varying the rate at which you fill it.

The problem is that it is difficult to control all the variables. The rate at which the charge pump leaks is controlled by components that have tolerances. Also, the rate at which the charge pump charges is controlled by the step pulse (size of cup).

Other CNC component manufactures also use this technology in the converters,. They require you to set the step pulse to a particular value to match what they need. This means that this step pulse is also then used for the stepper/servo drives and my be non-optimum.

On the DC-06 I put a monostable to ensure that the step pulse sent to the chargepump was always a constant width. This eliminated one variable. The component tolerances is a lot harder to fix. This results in the user having to play around with the steps/per value for the spindle axis to get the frequency of the step pulse correct. This means going back an forth to the axis setup screen which is a real pain.

The frequency needs to be high enough to get full scale voltage out of the DC-06, but if it is too high, the voltage will max out too early, resulting in a non-linear speed  response from the spindle motor.

I spent way too much time  supporting people setting up the DC-06. Don't get me wrong, once set up it is as good as the DC-03, but with the required support it wasn't cost effective.



2.PWM Control  DC-03 - This DigiSpeed accepts a PWM waveform from Mach3 where the Duty Cycle (mark/space ratio) represents the speed as a percentage of the spindle maximum speed. That is if the PWM duty cycle is 25% then the voltage out is 25% of the Analogue control voltage supply from the Motor controller.

Setting up is extremely easy. Measure the maximum spindle speed, then enter it into the Max pulley setting. That's about it.

The other advantage of the DC-03 is that is is more EMI resistant than the DC-06. Extra spikes on the DC-06 step line get converted in charge pump pulses that bump up the control voltage.


Relays - Both the DC-03 and DC-06 have two general purpose SPDT signal relays on board. These can be used for a variety of uses (or not at all) depending on what motor controller you are using and it's requirements.

Some Motor controllers require separate FWD and REV inputs, Some have a DIR input and an ENABLE. The two relays can usually be configured to operate as the controller requires.

Cheers,

Peter.

----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com
Re: Digispeed not working
« Reply #8 on: March 20, 2012, 09:31:11 PM »
Hi peter
Sorry for the late response, I see on the updated schematic there is no Reverse wire to the VFD. How will the M3 and M4 work?
Thanks
Katoh

Katoh,

Do you need to use reverse is the first question?

The parallel port has 12 outputs and 5 inputs so yyou need to engineer your system to work within these limitations (or use a 2nd parallel port).

EN012 http://www.homanndesigns.com/pdfs/EN012_V3.pdf is setup for 4 axes. If you are only using 3, then you can also use pins 8 and 9 for other things.

Also in the Engineering note I've set the breakout board to use pin 17 for the charge pump enable. If you did not need that, you could then also free up pin 17 for other use.

As to the DigiSpeed, it needs an output pin to control each relay. If you don't need to use both relays, then don't.

To control the relays via the spindle M3 and M4 codes (assuming you want to have reverse) you can do it as below.

1. First choose the output pins that will be use to control the relays. If you only have a 3 axis machine it could be say pins 8 and 9.
2. Wire up the DC-03, connecting say relay 1 to pin 8 on the MB-02V6
3. Wire up the DC-03, connecting say relay 2 to pin 9 on the MB-02V6
4. In the Mach3 outputs config tab, assign pins 8 and 9 to be controlled by Mach3 outputs, say Output5 for pin 8 and Output 6 for pin 9
5. In the Mach3 spindle config tab, assign M3 to turn on Output5 (Pin 8 thus relay 1)
6. In the Mach3 spindle config tab, assign M4 to turn on Output6 (Pin 9 thus relay 2)

So now, when you use M3, Relay 1 will turn on. If you use M4 relay 2 will turn on.


If you Motor controller needs a direction input and an Enable input, then the config is different. Assuming we are using Relay 1 to switch the enable and relay 2 to switch the direction, the setup would be;
1. First choose the output pins that will be use to control the relays. If you only have a 3 axis machine it could be say pins 8 and 9.
2. Wire up the DC-03, connecting say relay 1 to pin 8 on the MB-02V6
3. Wire up the DC-03, connecting say relay 2 to pin 9 on the MB-02V6
4. In the Mach3 outputs config tab, assign pin 8  to be controlled by Mach3 outputs, say Output5
5. In the Mach3 Motor config tab, assign pin 9 to be the spindle axis dir pin on port 1
6. In the Mach3 spindle config tab, assign M3 to turn on Output5 (Pin 8 thus relay 1)
7. In the Mach3 spindle config tab, assign M4 to turn on Output5 (Pin 8 thus relay 1)

Notice a couple of things here. M3 or M4 will turn on Relay 1. We need this as Relay 1 is the Enable so must be active in FWD and REV.
Relay 2 is now controlled by the Spindle axis direction output. Mach3 will automatically set this pin when a M3 or M4 is issued.

Note: In PWM mode, the Spindle axis Step pin is set to the pin that will carry the  PWM signal to the DC-03V3.

Hopefully the above is clear enough to understand.

Cheers,

Peter.

----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com

Offline otpco

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Re: Digispeed not working
« Reply #9 on: March 22, 2012, 06:28:30 AM »
Theree must be somthing wrong with us here in Canberra 3 of us and none of us can get them to work .I am going to build a test system so we can all have a play with it