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Loadcell S9M 2kN into Data logger ADC-24

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Loadcell S9M 2kN into Data logger ADC-24

Postby silhas » Tue Oct 15, 2013 7:26 am

Hello,

I've got some problems regarding plugging a loadcell into my data logger ADC-24.

The current situation:
I got a voltage supply of 24V, a data loader ADC-24 and a force transducer S9M. The force transducer requires a supply voltage between 0.5V to 12V, so I divide the voltage using 2 resistors of equal caliber (one serial connected and one prallel connected).
After the supply voltage is plugged in to the force transducer I connect the (+) measurement signal from the force transducer into the Data logger. The (-) measurement signal i plug into the AG.

The problem:
For starters I only get 4V over the force transducer. This can depend on the load, since the signal is 2 mV/V and thus the main voltage should change as well.
But the real problem is that i get 1960mV from the measurement signal inte the Data logger! This is way above the correct voltage, and I'm in a quite standstil on what to do...

wiring diagram and S9M datasheet in attachment.
Attachments
Kopplingsschema.png
wiring diagram
7844_download.pdf
S9M data scheet
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Re: Loadcell S9M 2kN into Data logger ADC-24

Postby Martyn » Fri Oct 25, 2013 9:42 am

I am not sure that the "Measurement -" and "Excitation -" should be connected together, surely that will short out one side of the bridge as shown in the datasheet. Additionally the supply needs to be between 0.5V and 12V so I would suggest changing the divider so that it is within the range not at one end.
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Re: Loadcell S9M 2kN into Data logger ADC-24

Postby silhas » Mon Oct 28, 2013 4:19 pm

Well, you are probably correct so I did some modifications to the wiring diagram.

I use a voltage regulator to lower the voltage to 5V, then I use the differential measurement to remove the common voltage. At zero load I get 0 voltage (which is correct), and I then get an increase in voltage as I increase the load. Unfortunately I get a lot of fluktuations in my measurements, and when I change +- voltole range I get completely different measurements. I was wondering why I get theese different measurements depending on my range?
Sometimes when I change the range to a different value and then change back I get a different value from the first time on the same range value even tho I dont change my load!

Is this due to incorrect settings or incorrect soddering?
Attachments
Lastcell med spanningsregulator.png
Loadcell with attached voltage regulator
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Re: Loadcell S9M 2kN into Data logger ADC-24

Postby Martyn » Tue Oct 29, 2013 11:48 am

Are you using your own program ? if so can you post it here.
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Re: Loadcell S9M 2kN into Data logger ADC-24

Postby silhas » Tue Oct 29, 2013 3:13 pm

Nope, I use Picologg Recorder.
The link shows some photos of the wiring and printscreens from the program. You can see the description (voltage range and current load) in the title of the images. The channel currently in use is channel 15 (differential measurement between 15 and 16).

http://imgur.com/a/pYjoG
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Re: Loadcell S9M 2kN into Data logger ADC-24

Postby Martyn » Wed Oct 30, 2013 10:00 am

Can you post a plw file so that we can take a look at the settings and data in an instance of Picolog here
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