T-Series/Precautions/T-NM

Precautions

Most Zaber positioning products have built-in home sensors. However, on the NM and T-NM series of devices, the home sensor is optional. Depending on the user’s application, the home sensor may or may not be required. Therefore, the home sensor on these devices is removable on most models.

WARNING! Never attempt to plug or unplug the hall sensor cable jack while the Zaber device is powered. This could result in damage to the device. Always disconnect power before attempting to install or uninstall the hall sensor cable.

The purpose of the home sensor is to set a reference or zero position to “sync” the controller position to the actual device position. On power-up, the default reference position assumed by the controller is typically the maximum range setting. In certain applications (for example continuous rotation at controlled velocities), position synchronization isn’t required, and the home sensor may not need to be installed.

If you choose not to install the home sensor, then DO NOT ISSUE A HOME INSTRUCTION (command #1). If you do, the motor will reverse indefinitely waiting for the non-existent home senor to be triggered. Instead you can set the initial position using the Set Current Position instruction (command #45).

The home sensor consists of a hall switch connected to a cable which plugs into the motion control device. A small magnet (included) activates the home sensor when it approaches within about 0.5mm of the face of the hall switch. If you choose to install the home sensor, you must mount the hall switch and magnet in the orientation shown with the black surface (south pole) facing the sensor. Typically the easiest way to install the hall switch and magnet is to glue them in place as shown in the image below. Be sure that the hall switch is mounted to a fixed part, and the magnet to a moving part, and that negative motion of the motor (ex a negative relative move, negative constant speed move, or counterclockwise turn of the manual control knob) brings the magnet closer to the hall sensor.