Electronics in the NOVAC-system

Electronics in the NOVAC-system   Based on BECK-IPC SC-12 embedded microprocessor ”System On a Chip” This is an 80186 CPU running at 20MHz. It has 10BaseT Ethernet, 2 serial ports, 512KB RAM and 512 KB Flash-ROM. A built-in multitasking real-time operating system stored in Flash-ROM provides web-server, ftp-server, and telnet-server. A command line interface that imitates MS-DOS can be accessed either through hyper-terminal to one of the serial ports or through the telnet-server. 1 serial port is connected to the spectrometer. 1 serial port is connected to your PC using hardware handshake. In addition communication can also be done through Ethernet to your PC. Baudrates to spectrometer and PC are fully configurable up to 115200 baud. 1 GB Compact-Flash memory card. Enough to measure in 277 hours (assuming 1KB/second of spectral data). The electronics has two pair of step/direction outputs to control two external stepper-motor controllers. In addition a stepper-motor controller is included on the board built on the TCA3727g circuit. With this controller the current in the stepper-motor windings can be set to four levels (now configured to 160, 106, 53 or 0 mA). It is now configured to use 160 mA when moving and 53 mA when not moving (to hold the position). Current is limited by chopping up the current using Pulse-Width-Modulation with high frequency (20KHz). Two solenoids can be controlled. The current through each solenoid can be turned on/off. In addition, the current direction through each solenoid can also be controlled. Input for a serial-port GPS and a compass with pulse-width-output. The compass outputs pulses with width 0.1 ms to signal 1 degree and 35.9 ms to signal 359 degrees. Low-cost compass with accuracy  10 degrees. The on-board stepper motor, solenoids, GPS and Compass are interfaced through a PIC16F84 chip that communicates through a 2-wire interface to the SC-12 CPU.

Measured power consumption for the electronics Determined by first disconnecting all equipment and then connecting piece by piece. Power consumption 1.7W  2.0W 2.2W 2.3W 2.8W 4.7W 5.7W SC-12 X Compact Flash   Stepper motor Hold Moving Compass GPS Double- spectrometer