Laser Energy Safety Controller
LESC – an electronic system which can measure laser pulse energy, analyze it and generate laser interlock safety signals. As well the system can measure the timing parameters of control pulses (period) and generate laser interlock safety signal if violation occurs.
LESC consist of two independent laser power measuring channels (CH1 and CH2).
Each channel implements the following functionality:
- Recognition of trigger signal to initiate measurements based on external SYNC and GATE signals;
- Supports Fast Photodiode (PD) for converting optical energy to electronic signal;
- Does amplification of that signal using two modes with different gain (MODE 1, MODE 2) to support wide range of measured laser energy;
- Converts analog signal into digital format using ADC convertor with specified sampling rate;
Rapid logic (FPGA) supports:
- Single pulse energy measurement (not accessible from outside);
- Statistics (mean, max, min and etc.) with specified frequency (10 kHz)
- Send current mean value to the comparison unit;
Safety logic performs checks:
- Level 1 exceeds over Time Frame 1 (>20% over 33ms for example);
- Level 2 exceeds over Time Frame 2 (>30% over 11ms for example);
- Interlock signal generator.
LESC incorporates also a comparison unit that can generate laser interlock signal when measurement from two power meter channels differs by more than tolerance value.