Yes, you are correct in the difference in operation. I am saying to just use a diode with CO2 settings in this case and only use the L-PWM or L-AN outputs without the L-ON. I never mentioned or suggested using the RF type setting.
With my 6442G, the L-ON comes up before PWM. This has been analyzed with a scope. Done so in an effort to implement a circuit to maintain a minimum input to the PSU (much like preignition) to allow proper scaling of power settings.
I also suggested that it would only be possible with both tubes enabled.
Yes, you cannot use both types at once. I understand what he is saying now. I did not pick up on that in his writing.
Enno, it would not turn off even if you selected RF with no preignition? In that case it should work basically the same as DC glass, just without the L-ON. Should allow a zero % PWM or analog value in this case.