YS110 Calibration - Part 1

In my previous post 4 wire vs 5 wire ttl strobe on this topic I solved the mystery of controlling a strobe via the Nikonos wired protocol. I just needed to use the extra wire. the next step was to "calibrate" my controller for my new YS110 strobe instead of my YS50 test unit (which I really did not calibrate...).

Initial tests with the dedicated RDY signal line worked perfectly but I quickly ran into problems when I turned the power setting down on my controller. At high power settings everything worked fine. At low power settings the strobe only fired once. If I cycled the power on the strobe it would then fire one more time. This behaviour initially made me panic a bit since it led me to think I had broken my real strobe! All of my initial research had been performed against an old spare YS50 that I did not use underwater - and I had a few spare units just in case. I had punished the YS50 strobe with no issues so this odd behaviour came as a complete surprise.

Once again, time to step back and think a bit. Power cycling the controller also allowed the strobe to fire just once. So it was not a strobe issue, it was most likely a controller issue. My strobe was unharmed!

A check of the RDY signal with the multimeter quickly revealed the problem: the RDY signal remained HIGH after a low power flash. The strobe was indicating that it was still ready to fire again immediately with no pause needed to recharge. I had assumed the strobe would always require some recharge time and had coded a HIGH - LOW - HIGH transition for the RDY line into the Arduino logic. The strobe held the RDY line HIGH. My Arduino was stuck waiting for the strobe RDY signal to go LOW. Power cycling the strobe (or the controller) satisfied this condition and allowed the next strobe cycle to occur.

With the YS50 the RDY and X were combined into a single signal line. Since the X was dragged LOW to fire the strobe the RDY signal always did a HIGH - LOW - HIGH cycle. Once these signals were split into 2 separate signal lines the RDY line was free to exhibit a different behaviour. At high power settings the RDY line did cycle LOW while the strobe recharged. At low power settings the RDY line remained held HIGH since there was sufficient leftover charge to immediately re-fire the strobe.

Replacement of the HIGH - LOW - HIGH cycle with a suitable debounce interval for the RDY line gave me a working (but not calibrated) YS110 quench controller. Next step was to calibrate the controller timings for the YS110 behaviour.