Breakout Board, Pendant, and Relay Box

A mounted Model C1 CNC4PC breakout board with opto-isolation on all lines; independent PC (USB) & stepper-side power supplies.
This board is in between the PC & the stepper controller. The smaller card is the LPT2 C22 pendant interface which uses USB power.
A schematic of the E-Stop, limit & AC relay-box circuits. The box has a metal cover.

LPT1 & LPT2 & three power cables.

Opto-isolated LPT1 stepper-motor controller, spindle/mist/vacuum relay box control, limits/homing, E-Stop inputs, & MPG2 pendant.
The right ribbon cable seemed to have allowed electrical noise from the steppers
into the pendant circuit so it has since been made into a direct connection.

CNC4PC C1 breakout board detail.

CNC4PC LPT2 pendant C22 interface board powered via USB. The C1 breakout board's +5V enable signal
goes through the two NC E-Stops & this board's NO (blue) relay which is controlled by the pendant's E-Stop button.

Mini-DIN chassis bracket.

This Manual Pulse generator (MPG2) has 4 pulses/detent. There are 100 detents/dial revolution.
It is very important to perform the Mach3 jog control CAL. Disable any Mach3 brains (see guide) that are not in use.
Handy Pulser specs.

Pendant stored in its supplied bracket.

Used extra scale brackets to allow hanging the pendant at three different bench edge locations.

Modeled after Tom Benedict's excellent relay box design. Since I used a plastic enclosure, I mounted the
Crydom D2425 solid-state relays onto a ¼" aluminum heat-sink plate. Heat-sink compound was thinly spread over the
entire back of the relays. The thick plate allowed for tapped holes to mount the relays (8-32) & the plate to the
enclosure (10-32, flush-mounted, 100º flat-head screws). Over spec on the relays should obviate any heat
problem as the 1/3-hp motor draws 11A maximum on start (5.7A running) at 120V & the relays are good for 25A at 240V.
Each relay controls two sockets. These relays are perfect for this application as they use TTL with built-in opto-isolation.
The plastic enclosure is 4¾" x 4¾" x 2⅜". Four felt stick-on feet on the bottom complete the box.

The Mach3 tutorial explains how to setup, enable & test the pin outs. Use LPT1 pins 16 & 17.
Test the relay box to make sure the motor stops when the E-Stop is pressed.