composit signal generator

[thepillar]

Hi Im new,
(I wish this window had spell check).
I need to make a composit signal generator.
Let me explain. I have several machines at work that use varying voltages to control axis movement. Supply voltages and the like. I need to summ these up with voltage controled amplifiers and put them on a single line to the "audio line in" port of a PC. There I can look at the various singnals using a virtual spectum analizer. I need 7 or 8 dc inputs 0 to 40 volts, frequency adjustable, and filterd from the other frequencys. I know it can be done I'm just looking for a jump-start from some of you brainiy wizards.
If I can SEE what the signals are doing on a real-time basis I can more reliably tune drives, find bad components, etc.

David.

 

[Russlk]

I am confused. Axis control signals would seem to be DC, so how are you planning to use frequency analysis? Some more explaination is needed.

 

[thepillar]

Newbie again,
I should have been more explicit. I was sitting my grandbaby and was a little distracted.

the signals I need to examine realtime are

24 vdc (servo valve power supply) looking for spikes and dips.
CNC Controler command voltage, ( + or - 10vdc)
enable voltage (12 -24) signal grounded when active.
servo valve spool position (feed back) + or - 12 vdc.
axis position feed back ( a liner pot attached to the hyd. cylinder providing a signal that represents the mechanical reaction to the servo valve.

all these signals can affect motion preformance while cutting metal, picking and placing, etc. If the enable signal is intermitantly droping out or if the power supply is dipping intermitantly, is the spool following the comand voltage, I can see it displayed as different frequency singnals on a virtual spectrum analiser.

My mental picture is that of a series of adjustable ocilators that can be individualy set to a specific audible frequency. The output of ocilators, (maybe a couple of 556 dips), would feed op-amps. The signals that I'm looking to observe would vary the gain of the op-amps. This in turn would be outputed to a signal summing buss that would feed the audio input of a PC.

It all looks good on a block diagram but the details of feed back, one signal influencing the others, do I need blocking resistors at the output of the op-amps, etc., is what condems me to brain-lock. I can etch a board. but expence of materials dictate that I limit the trial and error. I'm not that familiar with calculating the resistor & capacitor components. And the general fisability of the concept. Maybe you wizened ones can "see" a better way.

verry anxious to here your ideas,
David.

 

[Russlk]

What you describe is a Rube Goldberg contraption. If you hire an engineer to analyse the problem, a much simpler solution will be found.