Analog Monochrome Video Acquisition With Daq 6025e

[AnalogKid2DigitalMan]

Mic_Scale

What is the absolute range of voltage that your signal can span? The 6025 over-voltage protection can handle +/-35V (powered off) to +/-42V (powered on). Granted, exceeding the normal operating range is not suggested, but in a pinch to see if your app will work, I would skip the isolation and personally man the controls to see if things are working as planned. 

Any means (physical or electrical) to limit the range that the brightness/contrast controls span?

Here are some ideas to limit the range that involve a working knowledge of electronics (or Google)

(1) Back to back 10V zener diodes connected to the DAQ input going to the power rails- any positive or negative voltage over 10V would get shunted to the power rails and never reach the DAQ input. This approach may affect overall signal quality.

(2) Unity gain buffer op amp powered by +/- 11V supply. Again, any voltage approaching >10V will get clipped. Instrumentation op amps are of high quality.

(3) High speed opto-isolator operating in its linear range- this is a bit tricky, I know of it but do not know much...

Did you ever look into the Matrox frame grabber I suggested in the other thread a while back. I used a Meteor II to acquire a very unique video signal from a laser based 'camera' I designed.

[Mic_Scale]

Hello AnalogKid2Digi…

Good to talk to you again.

Yes, of course I've connected Matrox. They had a representative contacting me, after sending them our system's spec. After a few talks I understood that they do not have something appropriate, maybe because of our low H-Sync or because of having no clamp area in our signal, and so was with many other companies...

So we decided to work on the 6025e board, since our previous image system used a Daq board too.

I will examine your advice closely, thank you very much.