Controller Board Overview The controller board provides all of the low level hardware control and sensing for the system. The firmware runs on the controller CPU and is flash resident (rather than on the HDD and SBC). Voltage Generation • +/-15 VDC is used for PMD DACs • 10 VDC is used for DAC reference • 3.3 VDC is used for controller board logic Dual Port Memory Interface The dual port memory located on the controller board provides the communication channel with the single board computer (SBC) through the P104 connector. The SBC provides the coordinates, velocities, and flow rate commands for modeling to the controller.
The controller board provides the status/error information about the hardware back to the SBC. X, Y, Z Axis Control The controller takes the flow rate information from the SBC and sends it to the PMD processor. The PMD 2840 processor services the X and Y stepper motors and the model and support head servo motors. The 3410 processor services the Z axis stepper motor. There is no feedback from the stepper motors to the system (they are open-loop controlled). Material Motor Control The controller takes the flow rate information from the SBC and sends it to the PMD 2840 processors.
The PMD uses this information along with the encoder signals from the material motors to generate an output signal to drive the servo motors in the head assembly. Since the encoders provide feedback the material motors have a closed-loop control. Their position and rotation are precisely known at all times. Temperature Control The controller board reads the three thermocouple (T/C) inputs/signals - 2 for the head, 1 for the chamber. -8