Vibration Damping for Point-of-Sale Scale

Astronomers use these pads to dampen-out the vibrations picked up via the tripod legs of their telescope mounts. It's important when looking at an object in the sky at high magnification to eliminate vibration. I've read good reviews of these.

You might need to talk to a customer service rep at Orion to obtain a set of 4, since they are usually sold in sets of 3.

http://www.telescope.com/Accessories/Observing-Gear/Orion-RockStable-Anti-Vibration-Pads-for-Telescope-Mounts/pc/-1/c/3/sc/53/p/5155.uts

I don't want to be off topic or grumpy, but it strikes me that the system you are being sold is over sensitive and not fit for purpose.
I do my shopping most lunchtimes in Sainsburys and the system there has user hostile software and oversensitive scales.
To get back on topic, a piece of foam rubber/plasic (like you would use for a matress) with a paving slab on top of it should provide a stable base. If that doesn't work I'd reject the system and go for something simpler that actually works.
You are selling frozen yoghurt... what resolution do you need?
Del

I totally agree with you.

Good scales have an internal damping as well hardware as software. The product is not thought for normal usage conditions may be for labs but not for real life.

It could be possible that -if it is present - the damper is not set for the right conditions.

I too agree with Del; the scale is too sensitive for it's intended use. I would go with an analog scale. But if you insist, there is a product called an "isomode pad" which is a rubber cross rib pattern. There are different weight ranges to consider. Just plopping the scale down on a piece of rubber doesn't do the job. It has to be "pre-loaded" for it to be effective. Durometer also enters the picture.

What about putting a piece of black tape over the least significant digit on the display?

While I'm on a roll, my guess is you have a salesman who doesn't understand his product (or yours) trying to sell you a top of the range system with loads of 'benefits' all of which will be useless when it breaks down.
Who of us has been in a store where they "can't" sell you the goods because the tills have broken down despite you having the item in your hand and the correct money?
The world is beset by people selling stuff they don't understand to customers who think they want bells and whistles when they really need reliability.
To put in in appropriate language I'd respectfully suggest you want plain not chock mint chip.

The whole think smacks of a problem creation exercise.
You want to sell frozen yoghurt but end up re-building the premises. Kick the salesman out or ask for technical support.
Del
(Ahhh I feel better for that)

It sounds like you have the wrong type of scale for 'legal for trade' application...

http://legal-for-trade.balances.com/

If you want, till you change it, to use the scale the right way do the following:

- place a steel plate about same weight as scale under it and

- place a soft rubber piece between the plate and the table.

This way you decrease the own frequency of your system and this equivalent to a low pass filter for the waves generated by traffic around it. the amplitude will be less and your readings as well less disturbed.

Dbash - We are installing a point of sale computer system in a nearly completed...

Are you the shop owner/end user or the POS salesperson/company installing the system?

Out of shear curiosity, have you tried holding the scale in your hands and weighing a heavier mass - something much heavier than the typical yogurt serving? Does this seem to "settle" the scale or make it wildly worse? Have you tried the scale when no other people are in the building?

Have you simply moved the scale to another spot to see if it works, at all? Put the scale near a load bearing wall instead of the middle of the floor? Is it possible that the base is stable, and the platter is just oscillating for too long(taking 10 seconds to "settle"?)

What happens if you place the cup on the scale verrrrrrry carefully? Still bouncy? Can you add a standard tare weight to the scale - say a 2-4 pound mass, and set the software to deduct those pounds from every sale, to get the scale out of the .01 gram range and up into a range where the scale is less prone to micro-measure?

There are dozens of solutions and the other posts list a lot.

If you are the scale salesperson and you have no alternative scale to offer, perhaps you can save the sale by talking the contractor of the "nearly completed" shop and ask if they can do anything about the floor bounce - something less expensive than losing the sale. If there's significant deflection, maybe they need some columns and beams under that floor?

If you are the shop owner - don't pay for a scale that does not work for you. You have hundreds of options! You either need a more elegant version of the "black tape significant digit cover" because the scale is still reporting that digit to the register and you can't get a stable reading long enough to make the software ring the sale, or you need a time-averaging scale - an electronically dampened scale that makes an average reading over maybe 1/4 second or 1/2 second. Or you can try some of the mass-on-foam or springs methods suggested in the other posts.

Are you required by law or sales tax or some other regulation to measure/record/report more accurately than 1/4 ounce? If you worry about overselling a 1/4 ounce of yogurt are you possibly going to create a customer service issue? Are you planning to sell by the 1/8th ounce increment? Or smaller? Surely not.

Or... is the real problem that the floor is moving A LOT and you can't even get a one ounce accurate reading? Then don't fix the scale - fix the floor!!!

The scales have a damper built in.

If this doesn't work in the environment you are operating in then the damping may need to be adjusted (or turned on).

Could be the vibration exceeds the limits of the scales..too bad, either get new scales or try some energy absorbing padding as already suggested that doesn't interfere with the scale's movement.

If you preload the scales with say 500g and then Tare the scales does the hyper-sensitivity diminish?

The correct way to solve this problem is to perform a vibration analysis at the location you intend to use the scale. This will measure the frequency, amplitude, and direction of the vibration components as well as the days and times of maximum vibration. There are special accelerometers designed to perform these surveys. Lacking this information means that you will need to over-design the vibration isolation system to filter out the unwanted components. Basically, you need to mount your scale on a mass (like a granite or steel plate) and isolate the plate from the building with springs. There are active isolators (which also keep the scale level) and passive isolators. A shortcut to a complete analysis is to purchase an isolation table like the ones used to mount optical systems. They are available from a number of sources.

I forgot to ask what is the full scale of it and how big is the lowest weight you put on, and of course what have you noticed as signal movements and under which conditions, empty ? low loaded, Full scale ?