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Re: Mains power filter for digital scales?
Posted: Thu Jan 31, 2013 9:38 am
by DenisA
higginsdj wrote:DenisA wrote:Tony, they're an AY123. They're a $300 lab scale accurate to .02 of a grain which is 1 kernel of AR2208 or .5 kernel of AR2213sc (i dont split kernels).
They are brilliant and have really improved my loads though they can be very fiddly when they're in a bad mood. I've tried the angle of the dangle, pulling faces, yelling, standing back hiding and quickly running up when she settles, stand back and veeerrrry slowly approaching it, yelling again, punching the air, spitting, mumbling in a few different unknown languages, pulling my hair out (none left), talking sweetly to it and my next move was a sacraficial offering to the reloading gods, I had the cat ready and everything. Hence the UPS queries.
I've heard the GD503 are far better and don't drift though they are 5x the price.
Offical word from Sartoriuos.... (I have the AY123 scales as well)
1. These are cheap scales with cheap balance mechanisms (their words) so do not expect the world from them. (designed for lab use in controlled environments)
2. These scales drift with temperature changes, even small changes
3. A 3 degree change in temperature in a 2 hour period requires a re-calibration
4. Trickling onto the scale will inevitably cause the scale to drift
5. Stability setting is key and you need to experiment to find what works for you
6. These scales are highly sensitive to electrical fields and any change to the surrounding electrical field.
From my own experiments:
1. Don't bother to Tare the scales for the powder tray so you can measure just the drop. Know the weight of the tray and measure the all up weight (tray and drop). This will allow you to lift the tray, watch the scale's zero and reset the zero as required. Remember point 4 above.
2. Scale has to aclimatise before its drifting 'stops' (it never really stops but will get to a point where it is stable for short periods of time say 10-15 minutes). Remember, lights put out heat as does your body so its useful to have a thermometer right next to the scales to watch for temerature changes.
3. Remember the specs +/- 0.02gr read BUT ALSO +/- 0.03gr Linearity/repeatability so same drop can measure +/- 0.05gr
Hope this helps
Cheers
David
Cheers Dave,
Like you I've learnt to work with characteristics of these scales and they produce very even loads. I don't think that load in-consistancy is a cause of any dropped points I have. I've got many other excuses for those
.
I'm just looking to reduce the drift the scales get during peak hours of grid use. After peak hours its very good though still susceptible to many points that you've mentioned and still not completely drift free.
I'm just looking to save some time without going to the expense of upgrading the scales.
Very interesting post, thanks Dave.
Posted: Thu Jan 31, 2013 9:51 am
by aaronraad
Spotted this article on AccurateShooter.com last night. Looks like something I would even be able to tackle, if my A&D FX-120i wasn't already so much easier to use!
http://www.accurateshooter.com/technical-articles/reloading/line-noise-filter-helps-reduce-scale-drift/
Certianly great value for money if it works.
Posted: Thu Jan 31, 2013 10:14 am
by johnk
Posted: Thu Jan 31, 2013 12:02 pm
by DenisA
Definately worth a try prior to spending money on UPS's or invertors.
They may reduce "noise" that may be causing some drifting but I don't think they would solve power fluctuations. Both surges and drop off's could be causing drift also.
I'll head down to Jaycar today and see if they have any in stock. If the drift is only caused by noise then theres no point over capitalising.
Great find, thanks Aaron and John.
Posted: Sun Feb 03, 2013 9:10 am
by pazrs
Run it off a battery. A normal sealed lead acid battery.
No switch mode noise, no mains power no nothing.
I'd just cut the power adaptor cable in the middle and put some bullet connectors on it to change over from mains to battery.
Posted: Sun Feb 03, 2013 11:56 am
by aaronraad
pazrs wrote:Run it off a battery. A normal sealed lead acid battery.
No switch mode noise, no mains power no nothing.
I'd just cut the power adaptor cable in the middle and put some bullet connectors on it to change over from mains to battery.
I assume this works for scales that use an AC to DC transformer (with rectifier/diode?)? Don't think it would work too well for an AC to AC transformer!
Posted: Sun Feb 03, 2013 6:49 pm
by DenisA
My Sartorious is 15V so straight off the battery won't work.
A chargemaster is 9V so that wouldn't work straight off a battery either.
Posted: Mon Feb 04, 2013 8:19 am
by higginsdj
You can get DC-DC converters to step up a 12v source to 15v (Jaycar has them) but not sure if the Sartorious AC Adapters output is DC....
Cheers
David
Posted: Mon Feb 04, 2013 9:23 am
by DenisA
higginsdj wrote:You can get DC-DC converters to step up a 12v source to 15v (Jaycar has them) but not sure if the Sartorious AC Adapters output is DC....
Cheers
David
Yes it is DC. I'll check that option out. Cheers Dave.
Posted: Tue Feb 05, 2013 6:47 am
by higginsdj
Posted: Tue Feb 05, 2013 9:49 am
by DenisA
Hi Dave, I dont think that will do it unless I was running a 24v battery setup.
Adjustable DC-DC Converter
This handy unit will give an output from 3V to 15V DC@ 1.5A from an input of 6-28V DC, 2 odd amps. (The input voltage only has to be 3V higher than the output volts). The output voltage is regulated and short circuit protected. Will need modest heatsink for large voltage differentials.
* Measures 58 x 45 x 20mm.
* Ideal to run 6V stuff from 12V.
The way I understand it, and I stand to be corrected, a convertor will reduce voltage and an invertor will increase voltage.
Posted: Tue Feb 05, 2013 1:00 pm
by aaronraad
I got this one for my other electronic scales, but its no longer available:
http://reviews.dicksmith.com.au/8465-en_au/M9941/reviews.htm
but you probably want something like this:
http://dicksmith.com.au/product/M9926/regulated-international-voltage-power-adaptor with a 15V output option. Just need to make sure the 400mA is enough grunt.
Posted: Tue Feb 05, 2013 2:49 pm
by IanP
higginsdj wrote:You can get DC-DC converters to step up a 12v source to 15v (Jaycar has them) but not sure if the Sartorious AC Adapters output is DC....
Cheers
David
Chargemaster works straight off a 12V car battery, just make sure the polarity is correct. The device has internal voltage regulator and benchrest shooters use them off batteries all over the world!
Ian
Posted: Tue Feb 05, 2013 3:32 pm
by pazrs
DC Converter (Buck/Boost) is just adding more noise. Cheap plug packs are more noise again...
Posted: Tue Mar 19, 2013 10:41 am
by DenisA
Hi all,
I thought I'd update this thread.
I'm now running my Sartorious scales off a pure sign inverter which is running off an old car battery. I just have the battery on a maintenance charger while I'm not using it. The invertor cost me $120ish.
The scales still have a little drift intermitently though they are much, much better. I've been running this system for a few reloading session now and think its safe to say that its is definately an improvement over straight out of the wall.
Its saved me time and frustration and I think all things considered, the results are worth the extra money.
Cheers everyone for your input.