Electronics — Wire harness

Wire harness

Reference

How the machine is wired. The supply, what it feeds, and what plugs into the control board.

Contributor Jon

This page is the wiring. Where the PSU, the control board and the Orange Pi physically mount is Installing the electronics, and the render of where each one sits is on that page. Plugging them together afterwards is connecting the components.

The cables are yours to make, buy or order. Every cable on the diagram below can be bought ready made or built on the bench, with the Helpers pages and the bill of materials under each drawing. To have the whole set made in one go, send a cable vendor the pack on Ordering the wire harness, which also has the drawing, length and connectors of every cable.

1 Power supply

Model: MEAN WELL LRS-350-24
Output: 24V, 14.6A, 350.4W, single output
Enclosure: Custom 3D-printed box, fused AC input
Terminal block: 9 positions, numbered by MEAN WELL: 1 AC/L, 2 AC/N, 3 FG, 4-6 DC OUTPUT -V, 7-9 DC OUTPUT +V
DC outputs: 3 female DC jacks, each on a 100 mm (4 in) pigtail (PJ1 to PJ3) of 18 AWG (0.82 mm²) wire with a fork terminal on each of its 2 leads (M3.5 screw, 8 mm (0.31 in) wide at most). One pigtail per +V/-V screw pair: 7 with 4, 8 with 5, 9 with 6. Make the pigtails
AC input: Screws 1, 2, 3. Fed by the fused IEC inlet switch's own pre-terminated leads, so there is no cable to make
Loads: basically board v1.3, the USB hub and the Orange Pi buck converter. One jack each, no spare
Cooling fans: Not on the PSU. The control board's 40 mm (1.6 in) fan plugs into one of the board's four LED ports, see control board housing step 5. The Orange Pi's fan plugs into the board's own FAN socket.

2 Interconnect diagram

The PSU feeds the control board (W1) and two other loads, the USB hub (W2) and the Orange Pi (W3). The control board then drives the LED strips (L1 to L3), the limit switch (LIM), the steppers (S1 to S4 and CH) and the first servo adapter board over a 16-pin ribbon (RIB1). The cooling fans are not on the PSU. The IDs are the cable IDs on the order page.

2.1 Stepper pinout and polarity

Every stepper output on basically board v1.3 has the same pinout, pin 1 to pin 4:

Pin	Net	Coil
1	A2	coil A
2	A1	coil A
3	B1	coil B
4	B2	coil B

Pin 1 (A2) is the square pad.

This holds for all five JST-PH 4-pin connectors: J23, J27, J31, J35, J39.
The parallel 2.54 mm (0.1 in) headers next to each are wired identically: J24, J28, J32, J36, J40.

Coil rule. Pins 1-2 are one coil (A), pins 3-4 the other (B). Swapping the two wires within a coil only reverses motor direction. Splitting a coil across the 2/3 boundary is what actually breaks operation, so keep each pair together.

The 4 channel motors are NEMA 17 with their own JST-PH 6-pin socket, so cable S (S1 to S4) plugs straight into the motor and the shipped StepperOnline lead is not used. The chute motor ships as bare flying leads instead, and its cable (CH) is built: make the chute stepper lead.

Cable S plugs into the motor's own 6-position JST-PH socket, so the four board positions 1·2·3·4 land on motor positions 1·4·3·6 and motor positions 2 and 5 stay empty. Mark the polarity on each of the 4 channel steppers.

Which socket drives which motor, and how to check a motor's coils before you plug it in, is on connecting the components, step 2. The driver beside each socket is addressed in preparing the control board, step 3.