The new ShopBot CNC machine at WeDoClosets.ca came with an 8 spindle drill head on a second Z-axis. The motor turns all 8 spindles all the time, and the individual spindles are extended using air pressure. Each spindle can be individually extended or retracted when 24 volts is applied to any combination of the pneumatic solenoid valves.
The ShopBot controller can operate the solenoid valves, but there are not enough outputs available to address each spindle individually.
The four analog outputs from the ShopBot controller are being used to pass a binary number) from the design software to the Logic Controller. The Logic Controller takes the number and decodes it into one of 16 analogue signals using a SparkFun Digital/Analog MUX. Each of the sixteen analogue outputs break out into a pattern of drills extending, so output 3 might translate to “extend drills 1,3 and 5”. Diodes are used to keep the signals from one drilling pattern activating other drills through common wires. The signals activate 24 vdc relays which in turn activate the solenoids to extend the drills.