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nuphotonix
12-12-2011, 19:06
OK after installing the new pt30's I have noticed a problem right off. The prior 12k galvos and amp only used the (+) and the OV post. but my pt30's have a (+) (-) and OV post. When I use the cables that fit the cloner laser showcard dmx board, only two wires are being used. and those are to the + and OV

1. Do I need all three wires for the pt30 to work properly? + - and OV?
2. Can I just use the (+) and (-) posts instead and omit the OV post?

(OV)= as labled on the PDF blowup with no explination as to it's significance. Zero Voltage is my guess

Currently when I hook it all up for benching, all I get is static scribbles. w/no control over the scanners.

Thanks!

swamidog
12-12-2011, 19:32
my *guess*:

0V is ground. ignore it and hook up the +/- wires.

this is just a guess. i am not responsible if the universe implodes.


OK after installing the new pt30's I have noticed a problem right off. The prior 12k galvos and amp only used the (+) and the OV post. but my pt30's have a (+) (-) and OV post. When I use the cables that fit the cloner laser showcard dmx board, only two wires are being used. and those are to the + and OV

1. Do I need all three wires for the pt30 to work properly? + - and OV?
2. Can I just use the (+) and (-) posts instead and omit the OV post?

(OV)= as labled on the PDF blowup with no explination as to it's significance. Zero Voltage is my guess

Currently when I hook it all up for benching, all I get is static scribbles. w/no control over the scanners.

Thanks!

LaNeK779
12-12-2011, 23:01
your psu needs to have a + a -and a 0v post and you need to connect all three
if your psu is not of this type, you have to find an appropriate one

a +/-12v psu, if connected without the 0v, will supply 24v

my *guess* is that you need all three wires connected

whatsupadrian
12-13-2011, 07:17
I answered this in the hijacked thread bra. 0v = ground.

Mr.Coffee
12-13-2011, 16:41
Are you trying to connect the power for the galvos or the signal leads for the galvos?

Here's what you can do if it is the signal leads:
if the dmx board is single ended and not differential, it will only have two signal leads, whereas your "pt-30's" may have a provision for differential inputs. If that's the case, you want to connect the plus to the plus and minus to minus ignoring the ground.



if it's the power leads, then you'll need a different power supply.

this may help to explain differential outputs:
Hi all,

This topic can be really confusing and, the fact of the mater is that most people don't understand it. Let me see if I can provide a few clarifying points.

Differential is where there are two signals used -- DECODED BY THE RECEIVER in such a way so that noise picked up along long wires can be SUBTRACTED AND REMOVED BY THE RECEIVER.

This is different from so-called "single ended", because, although single ended uses two wires to communicate information (a "signal" wire and a "ground" wire), the RECEIVER does not decode or SUBTRACT the two signals and thus, noise picked up along long wires can not be removed automatically.

Now, there are a few very fundamental things to keep in mind here. First, the sensation of "single ended" or "differential" is purely ON THE RECEIVER, and has, essentially, nothing to do with the transmitter. It is the receiver (i.e. the scanner amps) that have the onus of "removing noise picked up along long signal wires".

OK, lets look at another point here. Differential is really helpful when you have long signal wires (i.e. like hundreds of feet). Differential does not buy you much if your signal wires are 5 inches, and all inside the projector.

Nevertheless, there are a few important points here. First, you would always want to use the + and - inputs on a scanner amp, and never use the ground (see another post). You do this regardless of whether or not your transmission system (in this case, some models of the FB3) is providing a true-differential signal or not. If it is not, you still get the full benefit of differential reception. Remember "THE ONUS OF DIFFERENTIAL SIGNALS IS ON THE RECEIVER, NOT THE TRANSMITTER".

So, in a nutshell, differential or single-ended outputs from the FB3 or any other controller won matter for you guys. Trust me, it just won't -- as long as you always use the + and - inputs from your scanner amp, you are already benefitting.

Now, one thing that you MIGHT benefit from is "twice the signal". If your scanner amp expects +10V and -10V to give you a full sized image, then this can't be had from the FB3 without our little (free) differential add-on. BUT!!! from what I have seen from these Chinese scanners that people send me to tune with the FB3, I can say a few things. First, these scanners really can't go very wide without either burning up, or being highly distorted. And second, the amps supplied with Chinese scanners don't seem to require -10V to +10V anyway.

So -- bottom line -- this is a long discussion for absolutely no end-benefit. Scanner amps already give you the full benefit of differential signals (as long as you actually use the + and - inputs). And if you are using Chinese scanners with your FB3, then you probably can't use a larger signal and wider scan angle anyway.

Best regards,

William Benner