FX120i drift

[kelbro]

It's now been a couple of hours with my powder pan on there and the reading was steady at 96.92 gr. I removed the pan and will see if it holds steady at -96.92.

There are some alternate zeroing options in the manual but I was not sure if/how that would help. When I made the post, I was curious if anybody had used alternate zeroing setting on these scales since I had not seen it mentioned.

 

[rlporter507]

I agree that it would be best if the calibration was closer to the subject weights but that's out of our control. I do run the performance checks with my check weight standards in the range of the powder that I'm using as a 'feel good'

i use the 100g to calibrate, then zero the pan, then put 23gr from my lyman weight set and it hits 23 every time.

 

[kelbro]

i use the 100g to calibrate, then zero the pan, then put 23gr from my lyman weight set and it hits 23 every time.

Same here.

Been sitting for a couple of hours at -96.92 at 50°. No drift.

That's what is puzzling to me. I can't see any drift except when I'm using it. That seems like it points to either an internal zeroing issue or static buildup. I'm going to go with static buildup.

Grounding the unit should help. It certainly can't hurt.

We will try to run a large batch later this week and see if the problem repeats.

 

[ronemus]

My basement is about 900sq ft and not heated or cooled except when I fire up the Big Buddy propane heater. I just remembered that I was running the heater that day. That was a variable. Raises the temp at my bench about 6-8 degrees.

A temperature change of 6+ degrees will cause a zero shift in almost any scale, and I have worked with high-end analytical balances in commercial and academic labs throughout my career. Laboratories maintain a constant temperature as a matter of course, and it is still necessary to re-zero periodically. It was always standard practice to zero the scale before taking a measurement.

In addition to the temperature change, your Big Buddy stirred the air which will also cause drift. I use 3 panels of the supplied draft shield, removing just one side for access. and have a large cardboard box with the front removed over the entire FX-120i/ATV3 setup. Even then it's necessary to keep my hands well clear (at least 1') to avoid shifts.

 

[kelbro]

A temperature change of 6+ degrees will cause a zero shift in almost any scale, and I have worked with high-end analytical balances in commercial and academic labs throughout my career. Laboratories maintain a constant temperature as a matter of course, and it is still necessary to re-zero periodically. It was always standard practice to zero the scale before taking a measurement.

In addition to the temperature change, your Big Buddy stirred the air which will also cause drift. I use 3 panels of the supplied draft shield, removing just one side for access. and have a large cardboard box with the front removed over the entire FX-120i/ATV3 setup. Even then it's necessary to keep my hands well clear (at least 1') to avoid shifts.

Thanks. That's right. Our labs were always kept at a constant temperature.

No heater today (I don't use the fan mode on the Buddy) and I observed no drift.

I think that re-zeroing periodically is a good best practice along with using known standards for a performance check.

 

[hoz53]

Thanks. That's right. Our labs were always kept at a constant temperature.

No heater today (I don't use the fan mode on the Buddy) and I observed no drift.

I think that re-zeroing periodically is a good best practice along with using known standards for a performance check.

my shop is no lab- i have tube heaters in there 6 or 7 feet over my fx120 one directly over it and if they are on it will go bonkers. im gonna move it or build a shield- mabie both among other things for it.

 

[sgav8r]

Another thing to consider. Your powder pan’s weight will fluctuate a little with residue (powder stains) that get left behind naturally with use. Those trace amounts of powder have weight, and the balance IS sensitive enough to detect it.

 

[Janeau]

Does .02 mean anything on a target?
Jackie wins all the time in benchrest using the charge master lite and weighing at the range.

No ot fors not. I compete in Benchrest with 6PPC and .30Br.
That scale is way more accurate than needed.