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Guys,
Can somebody shed some light on the startup sequence we'd need to follow if making our own controller for a 700 series KTP with ALE ?
Ie, the order in which the lamp, qswitch etc are turned on, if the lamp has to be slowly ramped up in terms of current, also turn off sequence as well etc.
Cheers,
Adrian
Adjust to desired current , then trigger q driver. Don't adjust current with q driver on. And don't disconnect q driver from q switch with driver on. If you adjust the current with the q switch on Hi RF , you will get the lovely sound of your optics being drilled to death !
I think you should have interlocks for e.g. water flow, water level, water temp which prevent the lamp from starting. That way, the water flow interlock will make sure the pump is running and the hoses are connected before the lamp starts.
The current should be set to a low value to start the lamp. Then you should adjust the lamp current slowly to reduce thermal shock. I put a capacitor on the middle terminal of the lamp current pot. If you're using a micro, you can limit the rate in software.
I think optic damage is likely to result with insufficient FPS. But I don't see any problem with adjusting the lamp current while the Q-switch is running. Of course, if you will explain the reason, I am happy to be corrected.Quote:
Originally Posted by Laser Zone
Here's what I do:
- check water level
- turn on external water, wait until air bubbles are gone
- make sure a.l.e. keyswitch is off and apply power to a.l.e. and pump
- set q-switch off, lamp current to simmer (~16A)
- turn on a.l.e.
- it's now safe to adjust the current and turn the q-switch on. I have never had a problem adjuting the current while the q-switch is on. The Q-switch driver has first pulse suppression so it is safe to turn it on while the current is up, but if you want to be extra careful, always turn the q-switch on when the current is low
simple shut down sequence (this is what I do)
- turn off a.l.e.
- wait a few seconds for the lamp to cool
- turn off system (a.l.e. and pump)
- turn off external water
paranoid shut down sequence
- reduce current to 16A
- turn off q-switch
- turn off a.l.e.
- wait a long time for lamp to cool
- turn of system
- turn off external water
paranoid shut down sequence
- reduce current to 16A
ADD leave lamp at 16A for a few minutes.
On the lab laser I used to take care of, the lamp often did not want to start at less current then we had last ran it at. So better to season the lamp at low current.
We had 3 years of lamp I-V plots and daily logs to back this up.
We could see the rod age in the plots, and see the lamp trends.
Nd:YLF rods slowly dissolve in the coolant over time, hence the aging.
Steve
I think there should be some mention of the KTP heater in there somewhere?
Regards, Dan.
Good point. If you have the old Oven Industries heater controller, wait for the LED to start blinking (it'll be on solid while warming up) before turning on the a.l.e. Mine warms up quickly enough that it's ready to go by the time I do everything else so I've gotten lazy and don't check it any more :-o
Quote:
Originally Posted by DMills
I think optic damage is likely to result with insufficient FPS.
It must have been that ! I ''once'' adjusted the current with the q on and heard a terrifying drilling sound. Found out my HR mirror was drilled . Luckily with the grace of god I was able to turn the hr mirror and continue to rock and roll !
Some good info here.
We are just about to start on a micro based controller, with all the trimmings. I like the idea of a smart controller that prevents anything potentially bad from happening!
I am doing it with relay logic, with only about 3 or 4 bits of state I can draw a complete state diagram for the thing which I just cannot do for any even slightly non trivial program running on an AVR or PIC.
Be careful of the RFI from the lamp ignition pulse if doing the micro thing, it is big, bad, and tricky to filter.
Regards, Dan.