PD in 3rd gen GSI galvo

[LesioQ]

Anyone of You guys knows more about how's this stuff working?
Most likely an optical setup but apparently with single emitter plus numerous detectors ? I was unable to find a pat. on this one.
Piotr.K

[mixedgas]

Looks capacitive to me. custom piece of ceramic.

Steve

[tocket]

Dang, that's simply beautiful. No cheap chinese crap there...

Do you have any pictures of the back? There's only two traces going to the PD, so I'm wondering if there are any components on the back of it. The markings on the PCB would suggest that it is indeed optical and the reflective surfaces on the galvo that the wavelength is in the IR region. I dare not chance a guess as to how exactly it works though.

[MechEng3]

Maybe magnetic? sensing the position of resonant field strength between the receiving plate assembly? If it's optical....dang small emmitter.....nice piece of work on that unit. Now seeing LA and LC on the board...sorry...long day.

[Laser Ben]

That does look like some kind of hall sensor.

http://en.wikipedia.org/wiki/Hall_effect

[mixedgas]

ONly one way to find out.

IR ccd, then a scope probe with a 1 turn loop. Watch out, GSI likes to excite the older sensors with 2-3 Mhz and 100-200V, that bites when you put a finger near it.


but 3 segments 120' apart instead of 2 or 4 orthagonal..... wierd.
Steve

[Lasernerd]

Very interesting!
wish I could see those dark sensor areas better..
I think that is a Die dead center of the sensor
The bond wires from the sensor are coupled directly to the PCB
Emitter pulsed,detector echoed at reverse Bias/polarity?
Looks like one of the bonding wires is sitting on the upper right mount
and missing from the lower left "B" contact of the sensor.
pretty sure that wont effect performance
could be all wrong here,who knows?

[LesioQ]

Here are a few shots more. The die thing in the center apeears not to have a single shiny surface like emitter, neither does it's top. If it's an emitter, then of what and which way The circular sections seem to have a bluish AR-coating. Definitely it has numerous PCB connections as the board is more than 2-layer. I was unable to visually trace it down precisely.

I think I will try to run it opened to see what happens , no fingers inside

What I'm basically after is running CT6800 using GS Lightning DSP driver. For this I have to mimic M-power galvo PD.

Piotr.K

[heroic]

It does look like a die in the middle of the ceramic mounted on the board there. Maybe the dark sectors of that ceramic are large area photosensors of some kind? They look a bit like photovoltaics or similar large area linear silicon detectors- last time I saw something like that it was a proportional detector for an X-ray fluorescence system. That would make the part on the galvo's axle a mirror.

[mixedgas]

OK, trace out which of the 6 pads are connected to what. If its 2 pairs of 2 and 1 pair of two, that would give us a clue. That looks like a mems of some sort. Giant magnetoresistive, optical, or capacitive, which one.....

what part # galvo is this?
What amp does it hook to?
Steve