I have noticed this several times with every electronic scale I have owned. I occasionally check them against my beam scale and are always accurate. When I remove the pan and the number goes negative because I zero it with the pan on the scale, it reads 73.5. As I am loading slowly over time that negative number gets down to 73 or 72.9. At this point I check my powder weight with the beam at its still on the money. 50 grains of powder is still 50 grains. Anyone have any expertise in this area that could explain what is going on. It makes one question the integrity of the loads.

I see it occasionally too.
I just re-zero the scale otherwise it drives me nuts.

what I think happens is the older and maybe current scales weigh in grams and converts to grains.
the brain just kind of gets glitched on the zero but still weighs what's put in it minus the zero it told itself it had.

I have one of the first RCBS digital scales and it is still working well. I have noticed that the pan weight does vary +- a tenth or two from time to time but it doesn't seem to affect anything. What I did early on was get a few 'standard' weights that I use to periodically check accuracy. Zeroing the scale with the pan on, the standards have always been within .1 gr. of their stated weight.
C.G.B.

Appreciate the responses. It does mess with your confidence a little but I continuely check it against my beam and loads are always correct. I know some of the older ones were effected by florescent lights or other electronics plugged into the sam circuit. Had a Dillon that would drift up 5 grains if it was under florescent lights.

That's a bummer MNiE, esp. since I just read an old article in Handloader that said fluorescent light was good to reload under because it minimised shadows.

I have been using electronic scales for so many years.

Secret is to calibrate them often, and zero often.

Mine is on all the time.

Only time I switch it off is when I travel abroad.

I don't know where the florescent light business came from but I have never seen it ( I have pretty much replaced all mine with led fixtures anyway). I do know that the my scale is subject to picking up a static charge, which can effect accuracy. The fix for that on mine was to ground the scale, which wasn't easy to do.
C.G.B.

Electronic scales drift zero for many reasons, such as temperature, humidity or air pressure changes. Stability is the key - also table should be stable and building itself (with wood floors scales may become drifting even somebody else is just walking in next room).

Also inner electronics can heat up or whatever.

Good scales will allow you to set different zero tracking levels etc. to compensate that behavior.

When I start to use electronic scales, I just heat them up at least 30 minutes prior weighting and then calibrate them. For this reason I love A&D FZ-300i-WP with internal calibration. It will calibrate itself by just pressing single button.

Jiri

quote:

Originally posted by cgbach:
I don't know where the florescent light business came from but I have never seen it ( I have pretty much replaced all mine with led fixtures anyway). I do know that the my scale is subject to picking up a static charge, which can effect accuracy. The fix for that on mine was to ground the scale, which wasn't easy to do.
C.G.B.

Fluorescent lights used to use 'starters' to help ignite the gas in the fluorescent tubes. The starters are a timed pulsing switch using a capacitor to provide the zap to help ignite the gas. As such they are not solid state so can interfere with electronics. I don't know about other chronographs but try turning on a Chrony chronograph in a room with fluorescent lights, the readout goes crazy.

I have a green RCBS one that I got many years ago. I recommend you unplug it when you aren't using it. When I leave it plugged in for weeks at a time not using it, it has to be reset.

quote:

Fluorescent lights used to use 'starters' to help ignite the gas in the fluorescent tubes. The starters are a timed pulsing switch using a capacitor to provide the zap to help ignite the gas. As such they are not solid state so can interfere with electronics. I don't know about other chronographs but try turning on a Chrony chronograph in a room with fluorescent lights, the readout goes crazy.

Yes and no:

Starter is in action only when fluorescent lights are switched on. No more in use later.
Chronograph crazy readings + fluorescent lights is the result of grid frequency. It can cause stroboscopic effects also on rotating parts (lathe turning for example).

Fluorescent lights also use Choke to stabilize electric flow etc. Modern lights use Electronic Ballast, working on higher frequency (ultrasound range), so it can maybe cause some interference.

Jiri

The only difference in man and boys is the cost of the mans toys!!