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Micro-Limit Switch -CMV103D/104C Mounting and Wiring

1.0 Introduction

Limit Switches provide a precise and effective solution for homing and collision avoidance to any machine as well as many other practical uses which include but are not limited to:

  • CNC Machines
  • Lasers
  • Machine Safety Solutions
  • Industrial Automation
 

2.0 Micro Limit Switch Assembly

This assembly guide is compatible with both the CMV104C (Short Arm) and CMV103D (Long Arm) limit switches (See Figure 1 below). These limit switch and plate kits offer a more robust solution over standard limit switch and limit switch mounting solutions.

Short Arm 1
Figure 1

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2.1 Tools

The tools required for this assembly guide are as follows:

2.2 Bill of Materials

ItemDescriptionSKUQuantity
1 CMV103C Limit Switch ELEC-CMV103C1
2 Limit Switch Plate v2PLATE-LIMITSW-V2 1
3M3-Cap Head Screw-12mmBOLT-M3-CAP-012-1PC2
4 M5-Button Head Screw-8mm SCREWS-M5-BH-8-12
5Spring Loaded Tee NutHARD-TNUT-SPRING-1PC2

Start by unpacking all parts received and checking each part off against the Bill of Materials mentioned above.

2.3 Micro Limit Switch and Plate Assembly

Please follow the step by step instructions below to assemble your limit switch and plate.

Figure 2
Figure 3

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Step 1. Insert 2x 12mm M3 Cap Head Bolts (3) into the two holes of the CMV103C Limit Switch (1) indicated by Figure 3 above.

Step 2. Referring to figure 4, line up the appropriate threaded holes of the Limit Switch Plate V2 (2) with the 12mm M3 Cap Head Bolts (3) so that the limit switch lever hangs off the front of the plate.

Step 3. Finally, screw in the 12mm M3 Cap Head Bolts (3) into the threaded holes of the Limit Switch Plate V2 (2).

Figure 4

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It is possible to invert the limit switch for right-side sensing as shown in Figure 4 above.

2.4 Micro Limit Switch Mounting

Figure 5

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Step 4. To mount the Limit Switch assembly, line up the limit switch arm with a suitable flat surface to trigger the limit switch lever on your machine. This can be a gantry plate, bearing or a V-Wheel.

Figure 6
Figure 7
Figure 8

Figures 6-8

Click on the image(s) to expand

Step 5. Insert the Spring Loaded Tee Nuts (5) into a V-Slot channel (Figure 6) and then line up the slot of the limit switch plates with the Spring Loaded Tee Nuts (Figure 7). Use an Allen key to fasten the M5-Button Head Screws-8mm (4) into the Tee Nuts through the plate to secure the micro limit switch assembly (Figure 8).

The limit switch installation location on CNC machines is user-preferred.  We suggest homing the machine in the front-left corner of the machine and therefore placing the limit switches in the following locations: 

  • Front of the Y-Axis gantry.
  • Left of the X-Axis gantry.
  • Bottom of the Z-Axis actuator.

Below are suggested examples of how to mount your limit switch on our machines. 

2.4.1 Outback CNC Mounting

Please see below for the recommended positions for mounting the Limit Switch Kit onto the OutBack CNC machine. 

Figure 9 - OutBack CNC: X-Axis Mounting
Figure 11 - OutBack CNC: Z-Axis Mounting
Figure 10 - OutBack CNC: Y-Axis Mounting

Click on the image(s) to expand

2.4.2 WorkBee V3 CNC Mounting

Please see below for the recommended positions for mounting the Limit Switch Kit onto the WorkBee V3 CNC machine. 

Figure 12 - WorkBee V3 CNC: X-Axis Mounting
Figure 14 - WorkBee V3 CNC: Z-Axis Mounting
Figure 13 - WorkBee V3 CNC: Y-Axis Mounting

Click on the image(s) to expand

2.4.3 OX Belt/Gear

Please see below for the recommended positions for mounting the Limit Switch Kit onto the Ox Belt and Ox Gear CNC machines. Please note that the Y-Axis mounting positions for the Ox Belt and Ox Gear CNCs vary as they use different aluminium extrusion profiles. The X and Z-Axis mounting positions remain the same.

Figure 15 - OX Belt: Y-Axis Mounting
Figure 17 - OX Belt/OX Gear: X-Axis Mounting
Figure 16 - OX Gear: Y-Axis Mounting
Figure 18 - OX Belt/ OX Gear: Z-Axis Mounting

Click on the image(s) to expand

2.4.4 Lead CNC

Please see below for the recommended positions for mounting the Limit Switch Kit onto the Lead CNC V3 machine. 

Figure 19 - Lead CNC: X - Axis mounting
Figure 21 - Lead CNC: Z - Axis mounting
Figure 20 - Lead CNC: Y - Axis mounting

Click on the image(s) to expand

3.0 Micro Limit Switch Wiring

Limit SW Pinout
Figure 22

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Figure 22 above shows the 3 terminal Pinout of the CMV10D/CM104C limit switch. There are two wiring configurations for limit switches which are dependent on the use case:

  • Normally Open Configuration (NO)
  • Normally Closed Configuration (NC)
 
NC Wiring
Figure 23

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Normally Closed (NC): In the normally closed configuration, the electrical contacts are closed (connected) when the switch is in its resting state or when no actuating force is applied to the lever. When the switch is activated or triggered by an external force to the lever, it opens the electrical circuit, interrupting the flow of current through the contacts. The controller is notified to this change in state. 

Choosing a normally closed limit switch configuration is recommended as it ensures that the electrical connection stays closed when the switch is at rest. This provides a reliable way to detect wiring issues such as a break in the wire or an intermittent connection. The Normally Closed configuration also lowers the chances of false signals caused by Electromagnetic Interference (EMI) in environments with electrical noise.

See Figure 23 above for the Normally Closed configuration. Make a connection between your controller’s signal pin and the limit switch NC terminal. Connect the GND pin from your controller to the COM terminal on the limit switch. 

NO Wiring
Figure 24

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Normally Open (NO): In the normally open configuration, the electrical contacts remain open (disconnected) when the switch is in its resting state or when no actuating force is applied to the lever. When the switch is activated or triggered by an external force on the lever, it closes the electrical circuit, allowing current to flow through the contacts. A signal is then sent to the controller. 

See Figure 24 above for the Normally Open configuration. Make a connection between your controller’s signal pin and the limit switch NO terminal. Connect the GND pin from your controller to the COM terminal on the limit switch. 

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