CNC router – limit switches

It took some time to find optimal places and constructions for the limit switches at the ends of the axes. Unlike what I would expect, for the Sainsmart control board the switches connect to  a common 5V instead of ground, so it’s not possible to use the chassis for a common ground connection.
Because the driver board has only 4 inputs and each axis has 2 limit switches the two switches for each axis are connected in series to one input.

Y-- limit switch
Y– limit switch
Y++ limit switch
Y++ limit switch
X++ limit switch
X++ limit switch
Z-- (bottom) and Z++ limit switches mounted directly at the THK KR33 linear actuator body
Z– (bottom) and Z++ limit switches mounted directly at the THK KR33 linear actuator body

One very important switch is the emergency stop. This is directly connected to the motor controller board so that it will work even if the driver software would hang. While waiting for the ‘production’ button to arrive I mounted a temporary one.

Temporary emergency button
Temporary emergency button

To make sure that also the spindle motor is stopped immediately in case of an emergency this is connected to the mains power via the relais on the control board.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s