FGM-3 Alignment and Calibration

[damiafix]

Many thanks epitopios for the links!

All the best, D.

P.S. Your Mag work correctly?

[epitopios]

FGM-3 Alignment and Calibration

Many thanks epitopios for the links!

All the best, D.

P.S. Your Mag work correctly?

I am still working on , need very good and standard calibration
I also have 2 dataloggers (E.P.E. and Deluxe) trying to mix with my Gradiometer , also these days i make a data logger from Everyday Practical Electronics 2004 ,Mag Logger 5, but i find difficult its softeware

friendly , epitopios

[epitopios]

FGM-3 Alignment and Calibration

Many thanks epitopios for the links!

All the best, D.

P.S. Your Mag work correctly?

what about yours , is it working ???
and what about datalogger ?
friendly epitopios

[damiafix]

Hi epitopios,
my gradiometer work, but I must to calibrate the two fgm-3 correctly, so the performances, now are very
low! I hope to finish it in the next days. For the datalogger, I wish to build a E.P.E. what
do you think about? What is the data logger that you prefer?

All the best, D.

[epitopios]

gradiometer+datalogger

Hi damiafix
until now I made two dataloggers
one is Data logger of Deluxe



and the other one is Data logger Kit877 of EPE of Magenta Electronics



but until now i can manage to mix my gradiometer with some of this 2 D.L.
because I have no help and knowledge about that
so , for now ......
or to show to us here, something to go on with that
if someone could help us , i aprecciated
friendly , epitopios

[damiafix]

Hi,
for the calibration of the two FGM-3, the lowest value that I can to measure from the
GND and pin 14-15 of the SCL007 is 0,15 volts; zero for me is impossible,
someone have got success and measured 0 volts?

Many thanks, D.

[damiafix]

Hi, I'm sorry, the tension of 0,15volts is between the GND ad pin 14-15 of the AD557 (Dac).
I've a question, if I use a right-angled aluminium section, as showed in the Epe project:

the two fluxgate sensors, will be directly and perfectly aligned?

All the best, D.

[Crowbar]

No, cause:
1) FGM-3 case isn't a true cylindric.
2) True magnetic axis won't match a case axis.

[epitopios]

callibration

dear Damiafix
I think that FGM-3 must not come close with anything metal ,
better soloution is panzerfaust at his foto
friendly , epitopios

[damiafix]

Many thanks for the replyes, I understand clearly! The thermal variations over time can misalign the two sensors, will always need a ceck before use, right? I Mention the use of aluminum because in this forum, many people have replaced the PVC pipes with it, and also in the EPE probe it's used. This aligment can to be perfect? In other words, pratically, it is possible to measure 0 volts on the DAC, or is it just a given theory?

All the best, D.

[fitz]

My Idea please have at it.

So in the pic I am using square PVC on the outside. The angle aluminum holds the sensors and has set screws in it to adjust the sensor against high density foam rubber. I think 4 screws on one sensor should let me get it just right. Do I need to adjust both sensors or will one do it???
Thanks
fitz.
[/IMG]

[Leto]

Do I need to adjust both sensors or will one do it???
Thanks
fitz.

Leave only one sensor adjustable .. or:
1) you will have hard time adjusting both sensors at the same time
2) you will double the chance that one of the sensors accidentially move in latter use

[fitz]

Thanks

I have already had a new idea and am looking into it. Because thermal is such an issue I need to get more mass into the mount. I am looking at getting a piece of 2 inch bar stock and having it center bored. Then I will have the ends where the sensors sit milled down so I can mount it much like I would have with the angle aluminum. I am going to draw this up and send it in for all of you to look at.

[fitz]

"perfect" is not always perfect is it, or is it?

I am working on a plan to have the sensor mount machined from a 5 foot piece of 2 inch round acrylic plastic. The ends will be center drilled on a lath. This means that they will be perfectly aligned when mounted. But I am wondering if this is really “perfect” as only the outer case of the sensors will be “perfect”. I am wondering if the internal components will still be out of alignment due to manufacturing differences. If this is the case I will still need to add adjustment screws. Does anybody have an opinion on this?
Fitz.

[damiafix]

I think that the sensors, inside, are different from each other, so a teoric linear aligment could not be perfect in pratic, for this reason. In this period I'm busy, so I can't continue the experiments with my mag...hope in the next days.

Best regards, D.