A few questions before I start building one

This topic contains 87 replies, has 6 voices, and was last updated by  gera229 4 years, 10 months ago.

Viewing 15 posts - 61 through 75 (of 88 total)
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  • #4038

    Chris
    Keymaster

    gera222, the keyboard/mouse should make no difference in your setup. You can check if anything is interfering with the parallel port timing by running a latency test ( instructions here). As for the vref, like it says in the hobbycnc documentation “vref = desired amps * .14″ so I think you’d want about 0.29. Glad to hear you’re making progress!

    #4101

    Chris
    Keymaster

    gera222, the keyboard/mouse should make no difference in your setup. You can check if anything is interfering with the parallel port timing by running a latency test ( instructions here). As for the vref, like it says in the hobbycnc documentation “vref = desired amps * .14″ so I think you’d want about 0.29. Glad to hear you’re making progress!

    #4039

    gera229
    Participant

    I’m using that blue transformer 24V 10A. Isn’t 29V too much?

    For the VRef part it says to use a power supply. Can I use the 241v 10a transformer set up as the power supply for this? (I bought this transformer: http://www.mpja.com/prodinfo.asp?number=7846+TR)

    I ask because the transformer setup is later in the manual, and this vref set up is an earlier step so I ask which power supply to use.

    Finally, before soldering the driver chips and hex chips, are those damaged by heat? How can I safely solder them on without causing damage (temperature, and amount of time to expose, how much solder to melt on them)?

    Since I am a beginner for the easier parts I would try to get the terminals hot so that the solder would flow all the way to the other side of the PCB. I don’t know if this is the proper method which worked even with capacitors, but I ask before doing the more serious part, the driver chips. Using a hakko fx888 with 1.6mm chisel/screwdriver tip.

    #4102

    gera229
    Participant

    I’m using that blue transformer 24V 10A. Isn’t 29V too much?

    For the VRef part it says to use a power supply. Can I use the 241v 10a transformer set up as the power supply for this? (I bought this transformer: http://www.mpja.com/prodinfo.asp?number=7846+TR)

    I ask because the transformer setup is later in the manual, and this vref set up is an earlier step so I ask which power supply to use.

    Finally, before soldering the driver chips and hex chips, are those damaged by heat? How can I safely solder them on without causing damage (temperature, and amount of time to expose, how much solder to melt on them)?

    Since I am a beginner for the easier parts I would try to get the terminals hot so that the solder would flow all the way to the other side of the PCB. I don’t know if this is the proper method which worked even with capacitors, but I ask before doing the more serious part, the driver chips. Using a hakko fx888 with 1.6mm chisel/screwdriver tip.

    #4042

    Chris
    Keymaster

    @gera229, you’d want 0.29V for the vref (not 29V!)–make sure to double-check your math.

    The HobbyCNC manual assumes you’d have an adjustable benchtop power supply for testing purposes. If you don’t you could see if there’s a local hackerspace or a lab at school that would have one, as they can be expensive. You could also just build the HobbyCNC power supply; if you got the HobbyCNC pro kit, you should have all the components you need to do this.

    For soldering, you can definitely damage the driver chips & other components by sitting on them with the soldering iron. Keep your tip clean, and before you touch the iron to the connection, get a bit of molten solder on the tip. This way heat will be passed more quickly to the connection, giving it less time to spread to the more sensitive parts of the component.

    I’m glad you are here asking questions & eager to get your build done, but my sense is that you may still need step back and read up on basics & do some practice boards. Things can get especially dangerous with the power supply, as you’re dealing with 120VAC and a giant capacitor, which can hold a charge even after it’s disconnected, and, as my dad used to say, “shock the piss out of you”– or worse. Clearly you’re not afraid to ask for help online–that’s a good thing–but don’t be afraid to seek out in-person help too. You might try this list of hackerspaces to find local folks that would have some of the tools & expertise you’re in need of.

    #4105

    Chris
    Keymaster

    @gera229, you’d want 0.29V for the vref (not 29V!)–make sure to double-check your math.

    The HobbyCNC manual assumes you’d have an adjustable benchtop power supply for testing purposes. If you don’t you could see if there’s a local hackerspace or a lab at school that would have one, as they can be expensive. You could also just build the HobbyCNC power supply; if you got the HobbyCNC pro kit, you should have all the components you need to do this.

    For soldering, you can definitely damage the driver chips & other components by sitting on them with the soldering iron. Keep your tip clean, and before you touch the iron to the connection, get a bit of molten solder on the tip. This way heat will be passed more quickly to the connection, giving it less time to spread to the more sensitive parts of the component.

    I’m glad you are here asking questions & eager to get your build done, but my sense is that you may still need step back and read up on basics & do some practice boards. Things can get especially dangerous with the power supply, as you’re dealing with 120VAC and a giant capacitor, which can hold a charge even after it’s disconnected, and, as my dad used to say, “shock the piss out of you”– or worse. Clearly you’re not afraid to ask for help online–that’s a good thing–but don’t be afraid to seek out in-person help too. You might try this list of hackerspaces to find local folks that would have some of the tools & expertise you’re in need of.

    #4043

    gera229
    Participant

    I actually have access to a school that I go to once a month, except this time the engineering teacher went out of town for 2 weeks. I’m actually building a router mount for their plasma cutter so that I can cut out my piece out of MDF wood, especially the electronics enclosure before I even put together the transformer and capacitor.

    He also has adjustable power supplies, what setting do I put it to (volts and current)? Once again I do not have access to anything for 2 weeks. I do have the PRO kit, but I’m not going to move on until I have an enclosure.

    My solder joints all look smooth and I read on basic soldering and did my research before I began. So I place the tip of the iron on the joint that I want to solder and apply solder on the other side?

    I find that if I apply solder right on the tip while it’s touching the joint (not pre-applying solder on the tip before touching the joint because that way it does not flow to the joint when applied to it because the solder still sticks to the tip) the molten solder would flow to the other side and that is when I move the solder wire to the other side of the joint as the molten solder would melt the new solder faster. That’s what I’m thinking is the safest way to do it. Because heating up the joint and having that melt the solder (instead of the iron tip melting it directly) takes a while and is dangerous as you say.

    Sadly, there are no nearby hackerspaces in my area according to the map that you linked to.

    #4106

    gera229
    Participant

    I actually have access to a school that I go to once a month, except this time the engineering teacher went out of town for 2 weeks. I’m actually building a router mount for their plasma cutter so that I can cut out my piece out of MDF wood, especially the electronics enclosure before I even put together the transformer and capacitor.

    He also has adjustable power supplies, what setting do I put it to (volts and current)? Once again I do not have access to anything for 2 weeks. I do have the PRO kit, but I’m not going to move on until I have an enclosure.

    My solder joints all look smooth and I read on basic soldering and did my research before I began. So I place the tip of the iron on the joint that I want to solder and apply solder on the other side?

    I find that if I apply solder right on the tip while it’s touching the joint (not pre-applying solder on the tip before touching the joint because that way it does not flow to the joint when applied to it because the solder still sticks to the tip) the molten solder would flow to the other side and that is when I move the solder wire to the other side of the joint as the molten solder would melt the new solder faster. That’s what I’m thinking is the safest way to do it. Because heating up the joint and having that melt the solder (instead of the iron tip melting it directly) takes a while and is dangerous as you say.

    Sadly, there are no nearby hackerspaces in my area according to the map that you linked to.

    #4044

    Chris
    Keymaster

    gera229, here’s a good overview of soldering techniques. Step 3 describes how to pre-solder your tip. The video on the page is a bit dark, but will give you a good idea of the amount of time you should be taking to make your solder joints.

    If you can get your hands on a benchtop supply from school, you’d want to set your voltage between 24-48V (that’s specific to the range that the HobbyCNC board can handle). You should not have to worry about the current when testing vref’s; current only becomes important when you’re running the motors.

    #4107

    Chris
    Keymaster

    gera229, here’s a good overview of soldering techniques. Step 3 describes how to pre-solder your tip. The video on the page is a bit dark, but will give you a good idea of the amount of time you should be taking to make your solder joints.

    If you can get your hands on a benchtop supply from school, you’d want to set your voltage between 24-48V (that’s specific to the range that the HobbyCNC board can handle). You should not have to worry about the current when testing vref’s; current only becomes important when you’re running the motors.

    #4045

    gera229
    Participant

    Since my build will be pretty similar to yours, and I will be using the 310 oz steppers from HobbyCNC I would like to know what current you like to use? It’s probably not 3A, but what do you use which works just as good as 3A except runs cooler?

    Also in the BOM it says to use 14 molex connectors. I could not figure out why you would need that many. It’s 2 molex connectors per axis just to do the conversion so a total of 6 molex connectors. If you were to extend each axis by 1 foot it would be another 2 per axis so a total of 12 molex connectors.

    #4108

    gera229
    Participant

    Since my build will be pretty similar to yours, and I will be using the 310 oz steppers from HobbyCNC I would like to know what current you like to use? It’s probably not 3A, but what do you use which works just as good as 3A except runs cooler?

    Also in the BOM it says to use 14 molex connectors. I could not figure out why you would need that many. It’s 2 molex connectors per axis just to do the conversion so a total of 6 molex connectors. If you were to extend each axis by 1 foot it would be another 2 per axis so a total of 12 molex connectors.

    #4046

    gera229
    Participant

    So I bought the alternate transformer and the documentation provided with the hobbycnc Pro Package in it’s drawing it refers to the more expensive brown transformer so the wiring colors are different and I am confused.

    Since you also have the blue alternate transformer can you tell me how the wires are connected?

    Also on the secondary it says 12V 12V on each side, is it still 24 volts even if the lead in the middle is not connected or anything? What is that lead in the middle?

    #4109

    gera229
    Participant

    So I bought the alternate transformer and the documentation provided with the hobbycnc Pro Package in it’s drawing it refers to the more expensive brown transformer so the wiring colors are different and I am confused.

    Since you also have the blue alternate transformer can you tell me how the wires are connected?

    Also on the secondary it says 12V 12V on each side, is it still 24 volts even if the lead in the middle is not connected or anything? What is that lead in the middle?

    #4047

    Taylor
    Keymaster

    Sounds like you’ve got a center tapped transformer. I suggest that you hook it up and test its outputs with a multimeter, then label them for future reference. You’re working with wall voltage here, so if you haven’t done this before you should work with a teacher or experienced hacker your first time out.

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