3-Axis Stepper Controller

[MP1]

Katsujinsetsunin, perhaps I did not understand your post, but it seemed to me that you will need 2 amp per motor for your CNC requirement but you wish to use steppers rated at 1.1A.
How have you figured the current requirement?
Also, I was trying to find the link to the board you have described which needs 8V minimum. Could you post a link to the project you are building?
BTW - newbie questions are always welcome on this forum.
Please tell us more about your project.

MP

 

[katsujinsetsunin]

Thanks for the reply MP - sorry if my post was unclear. This is the link to the CW Technologies stepper board: http://www.electronics-lab.com/projects/pc/008/

The stepper motors are rated at 1.1A (printed on a sticker adhered to the motor housing). I assume this rating is the current per phase, so if I choose to run the motors in half-step mode (activating two coils at once; a higher theoretical torque yield and finer motor resolution at the cost of a higher current requirement). Am I making a stupid mistake by assuming that if the motor requires 1.1A in full step mode, it will require double that (~2A) in half-step?

Regarding the voltage requirement, I am referring to an earlier post by administrator mixos (August 6, 2003) which states:
"The input voltage can be anything from 8V to 35V, but keep it at the voltage that the motor uses and not below 8V."

Hope this cleared up any confusion.

 

[MP1]

Hi katsujinsetsunin,
This is the project I thought you might be referring, but I could not find the reference to using 8 volts. I think mixos was talking about the requirements for the 5 volt regulator chip. The mention of 8 volts was so that you had enough voltage for the 7805.

If you are using 4 volt motors and 5 volts for the 5804, you could just use a 5 volt power supply and remove the 7805 from this board. Then drop the supply down by 1 volt for the steppers.

In reference to the current draw and stepping mode:
(Please bear with me as you probably know most of this)
Standard (hybrid) stepping motors have 200 rotor teeth, or 200 full steps per revolution of the motor shaft. Dividing the 200 steps into the 360º's rotation equals a 1.8º full step angle. Normally, full step mode is achieved by energizing "both windings" while reversing the current alternately. Essentially one digital input from the driver is equivalent to one step.

Half step simply means that the motor is rotating at 400 steps per revolution. In this mode, "one winding" is energized and then "two windings" are energized alternately, causing the rotor to rotate at half the distance, or 0.9º's. (The same effect can be achieved by operating in full step mode with a 400 step per revolution motor). Half stepping is a more practical solution in industrial applications. Although it provides slightly "less torque", half step mode reduces the amount of "jumpiness" inherent in running in a full step mode. It does not run faster, just smoother.

So, in conclusion, you will not be using more current in half step mode and you will not have more torque in half step mode. This mode of operation will only smooth out the stepping of the motor.

In regards to the power supply, give yourself some over head. Actually, an old computer power supply is great for running steppers. Linear supplies tend to run warm.

I hope the information is helpful.

MP

 

[alberto2]

I would like to drive ;Da water pump(220Vac) to cool during the cut of the metals through the 3-Axis stepper controller board how to do? is it possible?

 

[MP1]

Most production shops use a light oil for cooling and not water since water will cause the parts to rust. However, the answer is yes. You can use one of the switches to be activated whenever the position is not at home. When the switch is activated, you could use this signal from the switch to control a relay to the pump.

MP

 

[katsujinsetsunin]

Hello all! After a mishap which resulted in the mysterious burnout of three ICs (subsequently replaced), my controller board finally works However, using my software of choice (KCAM), attempting to run the motors in one-phase or half-step mode (by changing jumper position) results in a rather jarring back and forth motion (the motor fails to rotate smoothly in one direction, and instead jumps back and forth, several steps forward, several steps backward, with no net movement) - I doublechecked the solder connections on the controller board and they look alright to me - anyone else have difficulty with this or is this a software specific issue?

 

[GreekPIC]

Alberto, the cutting fluid is usually a 8-10% synthetic oil in water (ISO 220 or other water soluble synthetic oil).

You can use a pump operated by a relay connected to a unused pin in the parallel port (from what I see pins 5,14,16,17 are free) and configure your software to activate this pin when the g-code program you are running contains a M8 command. Similarly it should turn it off when reading a M9.

Using the home switches is not a good idea, because if the program calls for a tool change (M6) you are in for a shower...
Of course you could and should have a manuall override, but having the software control the pump is way cooler...

 

[alberto2]

Dear GreekPic, i think that your idea is wonderfull!! I use to engraving "KellyCam" software and it work good but i'm not very good in electronics! could you help me? Could you drawing a simple electronic schematic?Please.... or explain better your idea?

 

[GreekPIC]

More info here:http://www.dakeng.com/relay.htm, in th TurboCNC site.

I have no experienc with KellyCAM, but in TurboCNC in the hardware setup menu you can configure what every pin of the printer port does (step/dir for steppers, home switches, relays etc). Connect the circuit to an unused pin and configure it as the coolant pump in the menu. When the program reads M8 or M9 commands it will make the pin high or low accordingly.

You will also need a splash guard and a way to collect the coolant, filter it and pump it again.

 

[MP1]

Or a PNP version which causes the port pin to sink current instead of sourcing it. You can change the voltage and resistor values to suit your current/voltage needs.
I never source current to a relay from a micro or computer port. I always sink. Micros are better at sinking than sourcing.

MP

View attachment 35675

 

[GreekPIC]

Even better, thanks! What type of diode would be ok?

 

[MP1]

1N4001, 1N4002, 1N4003, any of these will be fine as long as the watt rating is ok with your circuit.

MP

 

[alberto2]

MP i see yours schematic but i have a question:
when i connect the circuit, a wire is the signal from lpt port but when i put +12volt and gng from power supply, i must connect also the gng lpt port to the power supply ground or it is a separete circuit with only +12 and gng of power supply and just lpt signal pin without lpt gng?
wich modify if i have 28.2 volt? as power supply?
I'm sorry but i'm not very good in electronics....

 

[MP1]

Hello alberto,
You will want to connect the ground of all circuits to the same "common" connection. The drawing I have posted is for a relay which uses 12 VDC for the coil. If you have a relay that will use a different value of power, then you will want to change accordingly. Please note the current and voltage capability of the transistor you are using.
I can't think of anything in a digital circuit which would need a 28 volt power supply. Why don't you use a smaller voltage? Do you have a device which needs this voltage level? Is this the voltage required for your stepper? If so, perhaps you could tap a lower voltage from a resistive divider. For example, if you are using a current limiting resistor for your stepper motor, you could use two resistors which make up this same value and tap 12 volts from the point where the two resistors connect. Such as this:
28V---/\/\/\/-+--/\/\/\/----MOTOR
^
12V
Or better, make a divider that will give you a little more than 12 and run it through a regulator such as 7812 and some protection diodes to keep it clean from the motor.


MP

 

[alberto2]

Mp thank you! I have made with fidocad a simple relay board trought your schematic. I think it wil be usefull to the comunity.
I hope that there aren't mistake!

RELAY BOARD
COMPONENT LIST:

R.1-4 4.7K
R.2-3 47K
R.5-6 560
D.1-2 1N4001/..02/..03 (see if the watt rating is ok with your circuit)
D.3-4 5mm LED
U1-2 2N3906
Relay1-2

 

[MP1]

Hi Alberto,
Please check the resistor locations. One is correct with the schematic but the other should be connected from base to emitter.

MP

 

[alberto2]

Thank you MP this is the ultimate version. you think that the relay status LED schematic and resistor value are correct?

View attachment 35695

 

[MP1]

Looks much better! The only thing I am not sure about is the LED. The LED drop down resistor is going to interfere with the coil resistance of the relay, depending upon the value. You will have this resistance and the coil resistance working in parallel. If you look at the parallel formula for resistors, you will see how you are changing the on/off characteristics of the relay by doing this. I do not know if this is a problem. It depends upon the coil resistance for the relay you are using. You might want to connect this status LED somewhere else where it will not effect the relay. This way, if you use different relays you will not take a chance on having a future problem.
You should figure the resistor value from the forward voltage of the LED. 560 seems a little low for this amount of voltage. It will be nice and bright. What is the Maximum current rating of your LEDs?

MP

 

[alberto2]

MP i copy the schematic of status LED in this site (SUB RELAY BOARD) if you think that there are problems the article must be correct. But probably is my not good electronics.

 

[MP1]

I think that article will be fine if you choose the right relays and the right LEDs. Unfortunately, the article did not list part numbers, so you do not know what they had in mind. It all depends upon the relay coil resistance and the current MAX rating of the LEDs.

MP