Need help using an example program

Areal Person

Hi,

I’m trying to get the “Inductor Demo” in the Inductive Sensor Demo program working
but I don’t understand how to hook up this SDF(sigma-delta feedback)
& SDI(sigma-delta input) area of the test circuit.

It's my understanding that the purpose of this program is to report
the frequencies of coils that are attached to the test circuit. Is this correct ?

I'm not an expert and I could not find a description of exactly
what the software does (One that I could understand [noparse]:)[/noparse] ). But Thats what it looks like to me. Am I correct.

Here’s a picture of the test circuit…

i192.photobucket.com/albums/z59/deleteallusers/sigma-delta.jpg

Where do these traces go ? What Propeller Pins do I hook them up to ?

It’s my understanding that I replace “L” with the coil I need
to read the frequency on. Is that right ?

And how do I know what size Diode to use ? will a 1N914/1N4148 work ?

Also, Here's the Inductive Sensor Program. It looks like the coil is used
for some type sensor here.
(I'm just a beginner)
obex.parallax.com/objects/49/

Thanks for the help,
-Areal

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I have a tree growing out of my head, but

what do you expect ? I'm a programmer.

Post Edited (Areal Person) : 10/17/2008 6:51:45 PM GMT

StefanL38

Hello,

I'm not really sure but if you take a look into
ADC.SPIN there are two constants

CON
SDF = 6 'sigma-delta feedback
SDI = 7 'sigma-delta input

so I guess PIN 6 and PIN 7

@Beau:

many other objects use parameters for PIN-assignments
was there a special reason to do it hardcoded as constants in the ADC-object ?

best regards

Stefan

Areal Person

I can't get it to work, I've tried several things.
All it shows as a reading is "0" (Zero).

I must be doing the setup wrong.

But how do I hook it up ?

I like the looks of this program, it will be very helpful to me if I can get it working.

Thanks for the help,
-Areal

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
I have a tree growing out of my head, but

what do you expect ? I'm a programmer.

Beau Schwabe

Areal Person,

"It's my understanding that the purpose of this program is to report the frequencies of coils that are attached to the test circuit. Is this correct ?" - Well, sort of...·an L-C combination will resonate at a particular frequency.· This program sweeps a frequency range plotting the response at each frequency.

There is no particular reason that the pin assignments are fixed... I probably should have made them selectable from the core program, but since this was just a demo I did not.· Anyway, the three pin assignments are as follows ... (You may change them within the CON statements to fit your needs)

Fpin = 0
SDF = 6
SDI = 7

Since the program only sweeps from 2MHz to 6MHz the coil should be in the range of 70uH to 630uH with a fixed capacitor value of 10pF.· If the coil is outside of this range, then you won't see any results.

"And how do I know what size Diode to use ? will a 1N914/1N4148 work ?" - I just used a junkbox diode either one you mention would be fine.




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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

Post Edited (Beau Schwabe (Parallax)) : 10/17/2008 9:21:00 PM GMT

Areal Person

Thanks Beau !

I'll be able to get it going now, I'm looking forward to working with it, you really do nice work.


Thanks again !
-Areal

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
I have a tree growing out of my head, but

what do you expect ? I'm a programmer.

Beau Schwabe

Thanks, I hope that helped

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.