[ Log In ]
[ Register ]
Laser Controller Tutorial Part 1: Wiring
In this series we'll be examining how to install the laser control unit. We will start with the basic wiring and move all the way up to software and functions.

Part 1:

The first thing we’ll do to get this laser controller working is to plug in the power, which is 24 volts. We’ll use a standard extension cord to hook up the mains to the power supply. The extension cord has 18 gauge wires inside. We’ll also use spade terminals, which we will attach to the wires with a crimper.

Strip the female end of the extension cord to expose the bare wire.

You should aim for about ¼” or 7mm length of bare wire. Then crimp the spade terminals onto the wire. Make sure the spade terminals are securely fastened.

Once the live, neutral, and earth ground wires have been crimped, we can connect them to the terminals on the power supply. The black wire is live, the white wire is neutral, and the earth ground is green.

Make sure the power supply is not on when you attach the wires. Also make sure that you aren’t touching any of the terminals while the supply is live. Check the power switch to ensure you have 110v or 220v mains selected. Once this is done, you can connect the plug from the power supply into your outlet.

Once connected, you should see the green LED lit up. This verifies you have power to the power supply. We will now test our outputs with our multimeter. Using two leads, we note a voltage of about 24.18 volts on each terminal. Now we are ready to connect the power supply to the laser controller.

We will now connect the V+ to the 24V terminal and the common to the ground terminal. Crimp the wires and attach the spade terminals as done before. Once this is done, connect the spade terminal to the power supply and the opposite end into the terminal block on the laser controller.

In the next part we will illustrate how to attach the stepper motor drivers to the laser controller.

Click Here for the Next Part in the Series

Laser Controller Tutorial Part 2: Connecting the Stepper Motor Drivers
In this series we'll be examining how to install the laser control unit. We will start with the basic wiring and move all the way up to software and functions.

Part 2:

Now we are ready to connect our three motor drivers to the controller and the power supply. On the laser controller we’ll be focusing on the terminals for X, Y, and Z. On each terminal block there are three terminals. 1 is DC5V, 2 is Pulse, and 3 is Direction.

The direction will be a high or low signal which will cause the driver to move in a particular direction, either forward or reverse. Pulse is a pulse of highs and lows that actually turn the motor.

On the driver, we’ll be focusing on CP+, CP-, CW+, and CW-. CP+ and CP= are for direction, CW+ and CW- are for pulse (step). Because we have a direction, pulse, and 5 volts on the laser controller, the pulse and direction are going to be connected to the minus and the 5 volts is going to be connected to the plus for both direction and pulse.

As a rule of thumb, if there is a ground, the pulse and direction are most likely going to be on the plus side, but since here there is a DC 5 volts which is positive, the pulse and direction will be negative. The pulse will be connected to the CW-, the direction to the CP-, and the DC5V will be connected to both the CW+ and the CP+.

We’ll be connecting two drivers here, to the X and the Y axes. We aren’t using a Z or U in this setup since we aren’t using an autofocus on our Z axis for the laser machine. Typically, we like to use a green wire for pulse.

We are using a 24 gauge wire since a higher gauge isn’t necessary for this application. For direction we typically use a yellow wire, which is what you see in the video.

After connecting the first two wires, we now use a white wire to connect the 5 volts to the CP+ and CW+. Since we’re using two terminals, we created a jumper to jump the wire from CP+ to CW+.

Next we repeat this process for the Y axis terminal, wiring identically as we just did on the X.

The next thing we need to do is connect the power supply to the drivers. We are using the 24 volt power supply in this case since we’re only using two smaller motors with relatively small amp draw. For larger / additional motors you may need to use a second power supply for the motor drivers.

To power the drivers, we will connect the common (COM) to the ground and the V+ from the power supply to the VCC on the driver. We’re using 18 gauge wire for this connection. Crimp as before with spade terminals to attach to the power supply.

Wire the second driver exactly the same as the first. Now the laser controller is powered by the power supply and the drivers are connected digitally to the laser controller with 5V pulse and direction. Both drivers are also connected to the power supply.

Click Here for the Next Part in the Series

Laser Controller Tutorial Part 3: Wiring Motors to Drivers and Calculating Steps Per Inch
In this series we'll be examining how to install the laser control unit. We will start with the basic wiring and move all the way up to software and functions.

Part 3:

At this point we've connected the power supply to laser controller and we also have the drivers connected. Now we are going to connect the motors to the drivers and configure them.

We're using NEMA 23 100oz-in motors. Normally you would wire these motors via a cable to plug into a connector, but in this demonstration we will be connecting the wires directly to the drivers.

Visit BuildYourCNC's page on the NEMA 23 motor to find the wiring diagram. We're going to use 4 terminals here, so we will not be using the center leads. We see the specification for the amps is 3.0 amps so we will need to set the driver at max amp capacity.

Don't worry too much about the voltage specification. The more voltage we apply to this motor the more velocity we can achieve on the motor.

The first thing we'll do is to cut the tips on the wires we don't be using so the bare wires won't make contact with anything we don't want it to. Remember, we're not using the center lead wires (Yellow and White).

The diagram calls for black and green to A. We'll wire the black to A+ and the green to A-. On the B coil, red will go to B+ and blue goes to B-. Repeat this process for the other motor and driver.

Now that both motors and drivers are connected, we will begin to configure them for proper operation. To set the dipswitches, refer to the table on the driver. We are using the 3.0 amp specification, so we'll set 5, 6, and 7 to "1" or "up".

To configure the microstepping, you need to consider the mechanics of what you're using to calculate steps per inch. We'll now look at the steps per inch formula.

We need the following information for calculate Steps / Inch


Motor Steps:



In this example we'll be using a 1/2" diameter 5-start lead screw.

For the specification of 10 / 5 starts we have 2 turns per inch. So we have 1/2 as our answer.

Formula Steps / Inch = (motor steps x microsteps per step) / (inches / revolution)

Now we will use algebra to isolate the variable we are looking for.

For 1000 steps per inch:

Steps Per Inch: 1000 * 1/2 = / motor steps (200)

500 / 200

Answer = 2.5 microsteps.

Because we don't have 2.5 microsteps as an option, we'll use 8 (remember this is 1/8th microstepping). So if we replace 2.5 with 8 and work backwards steps per inch will now become 3200.

The formula for drive pulley will be similar except we will be using the pitch and teeth of the drive pulley instead of the turns and starts of the lead screw.

Now that we know we want to use 1/8th microstepping, we see it is 0, 0, 1 on the chart. So we move the 3 to "1" or "up" to achieve 1/8th microstepping.