Moving forward with #FastBot #plotterbuild -- today is testing the motors and getting the cables properly labeled. Parts:
2x 3x8mm machine bolts
2x 3mm t-slot nuts
assembled machine with motor cables in place but not routed (don't do that yet)
assembled controller box
computer running CNC control software (Lightburn in my case)
Masking tape
Pen
Paper
Put the two 3x8mm machine bolts through the holes in the "ears" of the controller box, and spin on the two 3mm t-slot nuts.
We're temporarily mounting the controller box the wrong way around for easy access.
Set the machine with the rear motors towards you. Put the controller box on top of the rear rail, setting the t-slot nuts in the slot.
Tighten the 3mm machine screws to hold the controller in place.
Make sure the power switch on the controller is off. Plug in the USB cable to the controller and the computer.
Verify your software can talk to the controller (we tested this before, remember?)
Plug the motor power supply into the wall and into the controller box. Do not plug in any motor cables at this time.
Adjust settings in your software so that you can manually control the plotter to move very slowly (10mm/s) and just a short distance (10mm).
This is very important what I am saying next.
Never plug in, or unplug, motor cables while the motor power switch is on. Never.
You must always ensure there is no power going to the motors before you alter any motor cabling.
The penalty for doing this with motor power applied is sometimes burning up a driver, and this is a pain.
You can leave the USB cable in, and leave the power cable plugged into the jack, but you must always make sure the motor power switch is off.
During this part of setup, the Motor Lock switch should be off, and the Run/Pause switch should be set to Run.
With the motor power off, plug the Dupont end of the cable going to the pen lift to the 4 pin header next to the driver labeled Z. This is on the lower left looking into the controller box.
Now turn the motor power on. Nothing should happen, and that's good.
If you try to turn the pen lift knob, it should turn easily. Turn it until the pen slide is about half-way up.
Now flip the motor lock switch ON, and try to turn the knob. It should be much harder to turn.
Note: it is okay to overpower the pen lift motor to raise/lower the pen by turning the knob. This doesn't hurt anything.
Flip the motor lock switch off. We just verified there's power going through the drivers to the motors, and that's good.
Now in your software, click a button or do whatever to tell the Z axis (the pen axis) to go down 10mm.
The knob should turn slowly and quietly, and the pen slide should drop.
If the knob isn't slow and quiet and instead makes horrible rattling sounds, then the motor wiring is incorrect -- the coils are not wired to the right pins on the drivers -- and you need to go back and check your wiring from yesterday.
--> TURN OFF THE MOTOR POWER NOW
If the pen dropped when you told it to drop, then you know the Z axis wiring is correct. Get a small square of masking tape and label the left side of the Dupont connector with a Z. This is so you know which motor it controls, and which side faces the driver.
If the pen lifted instead, turn off the motor power, remove the DuPont connector, flip it around 180 degrees, and plug it back in. Turn on the power and test again. Now it should go dow.
Leave the Z axis unconnected and proceed with testing each of the other motors in turn:
X axis
Y axis motor 1
Y axis motor 2 (labelled A on the CNC shield)
If a motor moves the wrong way, flip the DuPont connector and try again.
Remember
You are looking at the rear of the machine. That means the X and Y axis movements are reversed as you look at them. Clicking Move Left should move the carriage to your right. Clicking Move Up should move the pen rail towards you.
Remember
Don't let the pen rail get significantly misaligned while you're setting up the motors individually. Just move the Y axis 10mm at a time, back and forth. Don't strain the machine.
When you've tested both Y motors separately, plug both Y motor cables in together and make sure both motors move in sync, and in the correct direction.
Remember
Never change motor cabling with the motor power on. (Hammering that home. It's a big deal.)
Okay now that you've proven all four motors work, in the correct direction, it's time for some joy.
Turn the power off, plug in all the cables, and turn the power on. Put a pen in the pen holder. Put a piece of paper underneath the pen.
In your software, make your plotter draw out "FastBot" in your favourite font. Not too big. Not too fast. And push Start.
You may need to fiddle with various settings to get the pen to hit the paper, or keep the pen from moving way too far.
A note: there are a lot of configuration options in the firmware that set movement distance, movement speed, movement acceleration, movement calibration, etc.
I set defaults in the firmware that should work fine for the machine I've described here. If your machine is different, you'll need to make changes (and that's out of scope).
You'll probably want to make changes anyway after you get familiar with your machine. This is where I urge you to go off and learn things.
Right, so the machine looks like spaghetti, but it works, so it's time to turn everything off, and tomorrow we'll do the final assembly.
Note: when switching off the machine, switch motor power off first, then unplug the USB cable. When switching it on, Plug in USB first, then motor power.
I don't advise leaving Motor Lock enabled unless you need it for a specific reason; this uses energy and also means you can't manually move the carriage or rails without a lot of force.
Shae M Puckett 🤖🖼