Proximity Sensors¶

A proximity sensor is triggered when Mach4 is opened, preventing movement.

Option 1: Power down machine and manually move machine away from limit switch.

Option 2: In Mach4, navigate to the Jogging tab then click the Axes Limits Override button. Carefully jog the machine away from sensor.

With this override turned on, limit switches will not stop over travel toward switches. Jogging in the incorect direction may result in damge to sensors.

Mach4 Users Guide

Proximity limit switches not connected to correct input ports.

Double-check the sensor cable connections at Plug and Play CNC Controller.

Note: A common mistake is swapping Y1 and Y2 sensor connections.

Sensor Connection Instructions

The proximity sensor, sensor cable, or CRP860-00E breakout board is faulty.

Test sensor to ensure LED on sensor body illuminates when a metal object is placed in front of the sensor. If LED does not illuminate, test sensor attached to a different cable. If LED still does not illuminate, replace the sensor.

If known good sensor/cable combinations are unresponsive on a sensor input port, the CRP860-00E breakout board may be damaged. Contact Us for further troubleshooting and replacement parts.

Sensor Connection Instructions

Proximity limit switch input pins improperly assigned.

To see what pins are receiving signals when a sensor is triggered, open Mach4 then select Diagnostics -> ESS -> Inputs

Ensure correct Avid Mach4 configuration is selected.

If not using Avid Mach4 configurations, ensure pins are mapped correctly in the ESS configuration

Mach4 profile or installation may have been corrupted.

Restore to a known good profile or reinstall Mach4.

Note: If using custom profiles or screen sets, save a copy of the Mach4 Hobby folder prior to reinstalling as some profiles may be usable after reinstall.

Restore Mach4 Profile

Reinstall Mach4

The CRP860-00E breakout board or ribbon cable is faulty.

Replace CRP860-00E breakout board and ribbon cable once the diagnosis is confirmed.

The dust collection hose may have triggered the proximity sensor. Dust hoses often contain metal coils.

Secure dust collection hose or shroud sensor such that a false limit cannot be triggered by moving hose.

Chips from the metallic material are triggering the proximity sensors.

The limit switches can be disabled in Mach4 to resolve this issue.

NOTE: With the limit switches disabled, the machine will not stop if a sensor is triggered. This means that the machine can be physically crashed into the sensors and bumpers if commanded to do so. Disabling the limit switches will not impact homing, and soft limits will be enabled after homing to help avoid overtravel in any direction. Do not make this change until you are familiar with the machine and understand the risks associated with this change. Always home your machine prior to operation.

To disable the limit switches in Mach4, select Configure ➝ Avid CNC Mach4 Configuration ➝ Advanced Options , check the Disable all limits checkbox, then select Save .

If you have concerns or questions prior to making this change, please Contact Us