force resteration scale

jimcav · Aug 14, 2008

Hello

I need a scale that is accurate to a thousands of a gram. I need to be able to interface to a micro logix 1500. The weighting section needs to be incorperated into the machine that we are making.

Thanks

OZEE · Aug 14, 2008

More info please!!

What's the total range you'll be weighing?

How do you want to interface to the 1500?

How are you isolating the scale? In the past I've done some microgram work -- at that range, fingerprints make a difference. You're in the milligram range -- air motion matters there, not to mention vibrations from passing fork trucks, large motors/air compressors, etc.

How long can you tolerate for a settling time?

LJBMatt · Aug 14, 2008

Among what OZEE asked what physical size does the scale need to be. I have found a lot of scale controllers have a devicenet interface you can purchase which would make integrating it into the Micrologix quick and easy.

Michael Bell · Aug 14, 2008

Weighing

Try Mettler Toledo Modulo WM series. They have RS232 capability.
We have used them very successfully for weighing small filter papers before and after use. Draught proofing is vital in these sort of applications.

mordred · Aug 14, 2008

also are you weighing in motion or static?

jimcav · Aug 14, 2008

my range will be 0 to 150 grams, as far as the interface i will do it anyway possible

TConnolly · Aug 14, 2008

150g x 1000 = 150,000 counts. Analog is obviously out. You will have to use RS232, Modbus, or DeviceNet. Contact Mettler Toledo - they are an AB encompass partner for weight measurement.

OZEE · Aug 14, 2008

jimcav said:
I need a scale that is accurate to a thousands of a gram. I need to be able to interface to a micro logix 1500. The weighting section needs to be incorperated into the machine that we are making.

jimcav said:
my range will be 0 to 150 grams, as far as the interface i will do it anyway possible

So - on a 150 gram range, do you REALLY need to know out to the thousandth of a gram!? The difference between 148.499 and 148.500?

How does it need to mount into your machine? To get that accuracy at that range, you will need to pay very careful attention to that. The answer to this question will also be important to identifying a scale for you.

mordred · Aug 14, 2008

Also at that precision level make sure you install a very good power filter. One option is to use a weight indicator that transmits in ascii via RS 232 port this will give you some flexibility in maintaining its accuracy particularly the noise filter parameters that they all include one good model is the 920I indicator as you can get whatever optional board you need to communicate to the micrologix

CharlesM · Aug 14, 2008

Here is another option

http://www.hbm.com/

force resteration scale

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