PDA-100 Photodiode Array Spectrometer Hack
Reverse Engineering the PDA-100 PHOTODIODE ARRAY DETECTOR
Absorption detector capable of measuring the absorbance spectrum from 190 nm to 800 nm. A deuterium lamp optimizes the UV range (190 nm to 380 nm) and a tungsten lamp optimizes the visible range (380 nm to 800 nm).
- Deuterium and tungsten lamps
- wavelength range from 190 nm to 800 nm
- 1024-element photodiode array optimizes spectral resolution
- built-in holmium oxide filter verifies wavelength calibration accuracy
Four analog outputs
Deuterium and Tungsten Lamp Power Supply
VOUT-A (Pin 2): High Voltage Level
VOUT-B (Pin 1): D2 Fil Voltage (Preheat Current)
VOUT-C (Pin 16): Thungsten Lamp Intensity
VOUT-D (Pin 15): Set Teperature
20 Pin connector:
(probably mostly feedback, no details yet):
Pin 2: DAC
Pin 6: R52
Pin 7: (5V?)
Pin 8: GND
Pin 10: goes to many resistors
Pin 11: (5V?)
Pin 12: Clock for HV
Pin 14: DAC
Pin 15: R?
Pin 16: R? Temp something
Pin 20: R54
To power the lamps:
Pin 12 needs to powered with a CLOCK signal for the High Voltage transformer. Don't know the exact frequency (can someone measure, please?). Works for me with 20KHz.
Sequence to power the Deuterium: Set high voltage to about 25% (4V), LED NO/F lights up. Then turn "D2 Fil" up until NO/F light goes off, ignition flash, D/OK should light green. Then turn D2 Fil down to zero again.