Jay Christopherson
Not An Admin
Precision Weighing Balances (http://www.balances.com), an authorized Sartorius Distributor, shipped me an AY123 (same as Denver MXX123, Acculab, etc...) along with the GD503 force restoration scale I ordered in order to run a comparison test for this site. I also tested them against a GemPro 500 scale that I already had. Basically, this is just a test of drift over two different periods of time.
*** UPDATE 11/03/2011: Added the Denver TP153 to the list
The first test was a "quick" test, where I measured the same weight 10 times, in the same order, about every 30 seconds or so. About the same speed as weighing out powder, maybe a bit slower. This took about 5 or 6 minutes. The second test was more-or-less an overnight test, where I measured the same weight in lengthening intervals, starting every 10 minutes, then every 30, then every 60, etc... you can see the time series on the included graphs.
SETUP:
- I used the same 100 GRAM Sartorius check weight for every test. This is a certified check weight.
100 GRAMS = 1543.23584 GRAINS
- I calibrated each scale within 30 seconds of each other before starting the test.
- I tare'd each scale within a few seconds of each other
- All three scales are connected to the same line conditioning PDU and are located in the same environment (right next to each other)
This is about as "scientific" as I could make it. I'm not a professional at all so YMMV with regards to the validity of this series.
NOTES:
- The Sartorius AY123 measures to the nearest hundredth of a grain (.00), INCREMENTS IN 0.02 GN DIVISIONS / nearest two hundredth of a grain
- The Sartorius GD503 measures to the nearest thousandth of a grain (.000), INCREMENTS IN 0.005 GN DIVISIONS / nearest five thousandth of a grain
- The GemPro 500 measures to the nearest half-tenth of a grain (.05)
- The Denver TP153 measures to the nearest hundredth of a grain (.00), increments appear to be in .02gn divisions
- When weighing powder, I weigh to the nearest .05 grain so any of these provide adequate (or more-than) resolution.
FIRST SERIES Quick Test:
* X-axis is weighing series iteration
SECOND SERIES Time-based:
* X-axis is a time series in minutes-from-0.
THIRD SERIES:
* This is a test of the AY123 in "Stable" vs. "Unstable" environment mode; GD503 for comparison
* X-axis is a weighing series iteration
Overall, the GD503 was the most consistent, never varying more than .005 of a grain, which is about 10X less drift than the next closest scale. The GemPro was "close" behind, never varying more than .05 of a grain. The AY123 was consistently variable and lost significant resolution over time. It was difficult to measure the AY123 because it rarely settled at a weight for longer than a few seconds- it would routinely come up with a different weight every few seconds, varying by as much as .04 of a grain. I settled on taking the first reading it "settled" on as the "official" reading.
The one thing this test does NOT demonstrate is trickling- the other videos that have been posted show that nicely. The GD503 gives you near instantaneous feedback on trickling whereas both the AY123 and GemPro 500 require a "trickle-and-wait-for-update" plan.
I've used the GemPro 500 for quite a while now and have found it to be fairly reliable- however, over one previous loading session I have seen it drift as much as .150 of a grain- I had to go back and re-weigh charges because of this. Therefore, I tend to tare it every 5 weighings or so which is probably overkill based on one case. I've not had that problem since so I am guessing something happened environmentally (maybe I bumped it or something). Overall, the GemPro is not overly sensitive to environment and settles fairly quickly and reliably.
I've loaded a few hundred rounds with the GD503 now- I have not found it to drift more than .010 of a grain in that time so I only tend to tare it once at the beginning of a load session. I have gotten extremely consistent velocities from charges loaded with this scale- well into the single digit standard deviations whereas previously, my best efforts usually resulted in low teens S.D.'s.
Based on my experience testing the AY123, I would not choose this scale to load powder with. The readings are just too variable. The *slightest* environment change (breathing, hand movement, etc...) cause large changes in results. I tried to load some rounds using this scale (backed by my GD503 to verify) and I couldn't do better than a few tenths of a grain, and that was with considerable effort. The Sartorius AY123 is really the wrong tool for the job when it comes to measuring powder.
Thanks to Precision Weighing Instruments for providing the AY123 for comparison. If you are looking for any of these scales, they can be found at Precision Weighing Balances:
Gem Pro 500 - http://balance.balances.com/scales/10/
Gem Pro 250- http://balance.balances.com/scales/9/
AY-123 - http://balance.balances.com/scales/1955
GD503 - http://balance.balances.com/scales/559
EDIT 10/4/2011:
Added new series of data to compare the AY123 in "Stable" conditions mode (default) vs. "Unstable" conditions mode, based on anecdotal evidence that the "Unstable" mode produces more consistent results. I did not find that to be so. In addition, I found that the weighing time for the "Unstable" mode was extremely slow- taking nearly 5 - 7 seconds per instance to complete a measurement. It then takes a few seconds to return to 0. In it's default "Stable" mode, it takes a second or so.
*** UPDATE 11/03/2011: Added the Denver TP153 to the list
The first test was a "quick" test, where I measured the same weight 10 times, in the same order, about every 30 seconds or so. About the same speed as weighing out powder, maybe a bit slower. This took about 5 or 6 minutes. The second test was more-or-less an overnight test, where I measured the same weight in lengthening intervals, starting every 10 minutes, then every 30, then every 60, etc... you can see the time series on the included graphs.
SETUP:
- I used the same 100 GRAM Sartorius check weight for every test. This is a certified check weight.
100 GRAMS = 1543.23584 GRAINS
- I calibrated each scale within 30 seconds of each other before starting the test.
- I tare'd each scale within a few seconds of each other
- All three scales are connected to the same line conditioning PDU and are located in the same environment (right next to each other)
This is about as "scientific" as I could make it. I'm not a professional at all so YMMV with regards to the validity of this series.
NOTES:
- The Sartorius AY123 measures to the nearest hundredth of a grain (.00), INCREMENTS IN 0.02 GN DIVISIONS / nearest two hundredth of a grain
- The Sartorius GD503 measures to the nearest thousandth of a grain (.000), INCREMENTS IN 0.005 GN DIVISIONS / nearest five thousandth of a grain
- The GemPro 500 measures to the nearest half-tenth of a grain (.05)
- The Denver TP153 measures to the nearest hundredth of a grain (.00), increments appear to be in .02gn divisions
- When weighing powder, I weigh to the nearest .05 grain so any of these provide adequate (or more-than) resolution.
FIRST SERIES Quick Test:
* X-axis is weighing series iteration
SECOND SERIES Time-based:
* X-axis is a time series in minutes-from-0.
THIRD SERIES:
* This is a test of the AY123 in "Stable" vs. "Unstable" environment mode; GD503 for comparison
* X-axis is a weighing series iteration
Overall, the GD503 was the most consistent, never varying more than .005 of a grain, which is about 10X less drift than the next closest scale. The GemPro was "close" behind, never varying more than .05 of a grain. The AY123 was consistently variable and lost significant resolution over time. It was difficult to measure the AY123 because it rarely settled at a weight for longer than a few seconds- it would routinely come up with a different weight every few seconds, varying by as much as .04 of a grain. I settled on taking the first reading it "settled" on as the "official" reading.
The one thing this test does NOT demonstrate is trickling- the other videos that have been posted show that nicely. The GD503 gives you near instantaneous feedback on trickling whereas both the AY123 and GemPro 500 require a "trickle-and-wait-for-update" plan.
I've used the GemPro 500 for quite a while now and have found it to be fairly reliable- however, over one previous loading session I have seen it drift as much as .150 of a grain- I had to go back and re-weigh charges because of this. Therefore, I tend to tare it every 5 weighings or so which is probably overkill based on one case. I've not had that problem since so I am guessing something happened environmentally (maybe I bumped it or something). Overall, the GemPro is not overly sensitive to environment and settles fairly quickly and reliably.
I've loaded a few hundred rounds with the GD503 now- I have not found it to drift more than .010 of a grain in that time so I only tend to tare it once at the beginning of a load session. I have gotten extremely consistent velocities from charges loaded with this scale- well into the single digit standard deviations whereas previously, my best efforts usually resulted in low teens S.D.'s.
Based on my experience testing the AY123, I would not choose this scale to load powder with. The readings are just too variable. The *slightest* environment change (breathing, hand movement, etc...) cause large changes in results. I tried to load some rounds using this scale (backed by my GD503 to verify) and I couldn't do better than a few tenths of a grain, and that was with considerable effort. The Sartorius AY123 is really the wrong tool for the job when it comes to measuring powder.
Thanks to Precision Weighing Instruments for providing the AY123 for comparison. If you are looking for any of these scales, they can be found at Precision Weighing Balances:
Gem Pro 500 - http://balance.balances.com/scales/10/
Gem Pro 250- http://balance.balances.com/scales/9/
AY-123 - http://balance.balances.com/scales/1955
GD503 - http://balance.balances.com/scales/559
EDIT 10/4/2011:
Added new series of data to compare the AY123 in "Stable" conditions mode (default) vs. "Unstable" conditions mode, based on anecdotal evidence that the "Unstable" mode produces more consistent results. I did not find that to be so. In addition, I found that the weighing time for the "Unstable" mode was extremely slow- taking nearly 5 - 7 seconds per instance to complete a measurement. It then takes a few seconds to return to 0. In it's default "Stable" mode, it takes a second or so.
