Digital control system DCS 06/08

The digital control system (DCS) was designed to control STM scanning modes, lithography, getting the surface spectral characteristics, etc., while ensuring low level of noise and high speed.

Download a general description of DCS 06/08:

 icon DCS 06/08 of Sigma Scan (130 kB)

 

Functionality:

— Advance/retraction of the probe vis-à-vis the sample surface;
— Digital stabilization of the gap between the probe and the sample surface along Z axis;
— Positioning of the sample surface relative to the probe;
— Scanning of the sample surface;
— Spectrometric measurement of the sample surface in the scanning tunneling spectroscopy mode;

 

The central part of the DCS is ADSP/ADC board. This board carries a DSP with executable program memory and flash memory. The main part of the program executed by the DSP is a PID-controller with various additional functions performed simultaneously, such as capturing data from the ADC, generating signals to the DACs output etc. The program memory is loaded from a flash ROM immediately after power-on, or directly from a PC file. The firmware in the flash memory can be updated as well.

 

The software consists of two main parts:

– The high-level program running on the host computer controls the STM by sending commands to the DSP, manages PC-DSP data exchange, displays current parameters and characteristics, scan and measurements results, and performs mathematical data processing.
– The low-level program (firmware) loaded into the DSP memory controls the functional units of the system and manages data transfer to the host computer.