restriction magnetic field of coil?

Mehmet TASPINAR

Hi,

I have a some problem about coil designer:
We have to mounted this sensor into the brass metal, but when I put it into brass material the switch is always on (Look at the picture please)
Q1: How can I eliminated magnetic field back side of the coil, side of circuit

Q2: I have used 4 layer series coil. Top layer, Inner Layer2, Inner Layer3 and bottom.
Is that better to use detect target with top and inner layer2?
And is that better using inner layer3 and bottom layer connected to ground for eliminated magnetic field?

Please give me some advise this issue?

All the best

Mehmet

over 9 years ago

0 Chris Oberhauser66 over 9 years ago

TI__Genius 14270 points

Hello Mehmet,

Would you be able to use some ferrite shielding on the back side of the sensor? This would capture the field on one side and minimize the effect of the brass. My colleague Ben Kasemsadah has written a blog post (e2e.ti.com/.../inductive-sensing-how-to-shield-from-metal-interference) which provides additional details.

Regards,

ChrisO

0 Michael Stout over 9 years ago in reply to Chris Oberhauser66

TI__Genius 16890 points

Hi Mehmet,

You can also use a ferrite core like the PH5.6/3.6 or PH14/7.5 made by Ferroxcube that directionalizes the field out the front of the core.

Mike

0 Mehmet TASPINAR over 9 years ago in reply to Chris Oberhauser66

Intellectual 355 points

Hi Chris,
This post was actually useful for me, thank you
May I know Mr Ben mail address if there is no problem?
You can also send it to my mail address: tmehmet@gmail.com
All the best,
Mehmet

0 Evgeny Fomin over 9 years ago

TI__Genius 9300 points

Hello Mehmet,

Have you readjusted the thresholds after placing the coil inside the brass housing?

0 Mehmet TASPINAR over 9 years ago in reply to Evgeny Fomin

Intellectual 355 points

Hi Evgeny,
No, I didn't
But I have to do replace into brass metarial.
If I reduce threshold, I have to reduce distance from 4mm to 2mm. The sensor distance should be 4mm.

Best regards,
Mehmet

0 Evgeny Fomin over 9 years ago in reply to Mehmet TASPINAR

TI__Genius 9300 points

Hello Mehmed,

Once you place the coil into your brass holder, set the target at the required switch-on distance (4 mm), measure Proximity Data. Then set the distance to the desired switch-off position, measure Proximity Data. those two values are your new thresholds.

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restriction magnetic field of coil?