Homing Switch Overview

This document assumes that the switch or sensor will be used for homing but applies to all switch and sensor types.

This document provides wiring and input configuration information based on the type of switch and wiring you are using. Due to the large variety of switches on the market we are unable to provide individual support for your chose sensor. This document will help you identify and connect your chosen sensor or switch and provide information on how to connect. Please use this in concert with the information that came with sensor. This document seeks to help identify Electronic switches such as proximity, optical or hall effect with the use of a voltmeter and some basic testing.

Wiring also provided for mechanical switches such as lever, push button and magnetic reed switches at the bottom of the page. Use a continuity tester to identify if your switches are normally open or closed and wire accordingly. Always used normally closed if you have the option of additional safety.

HINT: All MASSO inputs are optically isolated and require a voltage of 5V to 24V from your sensor to register an input.

INFORMATION: To invert an inputs logic, highlight the input and press the spacebar on your keyboard. All Homing inputs must show LOW when not operated and change to HIGH when active.

INFORMATION: If you are unsure what homing switch to purchase and how to wire it then MASSO supplies a Homing switch with full wiring instructions available.

Powering your Homing sensors

Power for the homing sensors on MASSO G3 or MASSO G3 Touch can be provided from:

• Directly from the MASSO power supply distribution point.
• A separate power supply which shares a common ground, (-ve rail), with your MASSO power supply
• The Auxiliary power terminals built into MASSO. These are the Red and Black terminals found between the input and output terminals.

WARNING: The installation of a 1 amp fuse between your Power Supply and MASSO is required to protect against an accidental short circuit of the auxiliary power connectors on MASSO, such an event can damage the controller beyond repair.

CAUTION: Power and Ground terminals provided on the controller are only to be used for very low current signals. Connecting high current loads can damage the controller beyond repair. 

How to wire the MASSO homing sensor

MASSO Homing Sensor

Identify your Electronic homing switch type

Complete the following testing matrix using the steps below to identify your sensor type and required wiring / input setting.

Step 1: Connect your sensor to a suitable power supply

Step 2: With sensor in normal state measure the voltage between the output & +ve and the output &-ve record the results in the table below. If the voltage is greater than 3.5 volts record a 1 otherwise record a 0. Ignore the polarity shown on the meter.

Step 3: Trigger the sensor and measure the voltage between the output & +ve and the output &-ve record the results in the table below. If the voltage is greater than 3.5 volts record a 1 otherwise record a 0. Ignore the polarity shown on the meter.

Electronic Homing Switch Matrix

Step 4: Find the matching table below and use the wiring diagram and input configuration indicated.

Sensor Types and Wiring

Type 1

Type 2

Note: Invert MASSO input for Type 2 sensor

Type 3

Type 4

Note: Invert MASSO input for Type 4 sensor

Mechanical Homing Switch connection

There are 2 ways of connecting Mechanical switches but the preferred method is using a normally closed switch which is the more fail safe method of the two. Should a homing switch wire break, the homing input will go high making MASSO think the Homing switch is already active so will attempt to back off the switch and will stop after 10mm.

In case of normally open switches a broken wire will not change the input and MASSO will drive the entire distance allowed before giving a homing alarm.

Note: Invert MASSO inputs when using Normally closed switches

Additional Resourses

For additional information on Homing and how to set it up please see our documentation on setting up homing.

Setting up Homing

Detailed video on setting up Homing settings in MASSO

Mounting the Homing sensor

Traditionally Homing sensors and limit switches are placed at the extreme ends of the Axis travel and are wired back to the controller.

This is wasteful of system resources, hardware and wiring.

Homing sensors work very well when only homing and soft limits are used.

When using your Homing sensor as both homing sensor and Hard Limit sensor it is recommenced that you mount the Homing sensor on the moving axis carriage and place a trigger for the sensor at each end of the Axis travel. The allows the one sensor to be triggered at each end of it's travel with minimal hardware and wiring required. see the example below.

Note: the trigger for the sensor must be such that the sensor remains High throughout the homing process.

Example axis with the sensor mounted on the moving carriage and the trigger mounted on the stationary rail

If converting an existing machine with Homing and limit sensors at each end of the axis these will need to be multiplexed and connected to the axis homing input on MASSO.

How this is done will depend on the sensor or switch being used. In this case both sensors or switches will need to be connected to the required axis homing input in such a way that the trigger of either senor or switch at either end of the axis will change the homing input from Low to High. Some examples can be seen below.

Multiplexing homing sensors on the same axis for Hard Limits

If your machine has sensors at each end of an axis that you wish to use as Hard limit switches they can be multiplexed together and connected to the axis homing sensor.

The method used will depend on the type of homing sensor. Please be sure to identify the type of sensor you have and wire it accordingly.

Do not mix different sensor types on the same axis.

Below are some examples of how two sensors on the same axis could be connected to allow either sensor to trigger the homing input.

For the correct method to use to multiplex your homing sensors please consult your homing sensor supplier

Example of how multiple homing sensors may be multiplexed