A&D FX-120i AutoTrickler Setup: Exact Scale Settings, Calibration and Fixes

This FX-120i AutoTrickler setup guide gives the exact function-table settings for the A&D FX-120i, on sale for $699.00 (regular $1,495.00), in stock.

The A&D FX-120i (122 g x 0.001 g, about one-second stabilization) is the scale most reloaders pair with an AutoTrickler V4 powder dispenser, because it is fast, stable and reads to 0.001 g (1 mg). The AutoTrickler talks to the scale through its RS-232C serial port, so the scale has to be told how to send data. This guide gives the exact settings, what each one means, and the fixes for the most common setup problems. The settings below come from the AutoTrickler V4 user manual (January 2025) and match the parameter tables in the A&D FX-i instruction manual. If you are still choosing a scale, see our best reloading scale comparison. For everything else in the FX-120i menus, see our FX-120i manual, explained.

What you need

• An A&D FX-120i or A&D FX-123 (the FX-123 package includes a 100 g calibration weight and reads in grains). Deciding between models? See our FX-120i vs FX-120iN vs FX-300i comparison.
• An AutoTrickler V4 with its serial port connector, cable and power adapter (sold separately, not included with the scale).
• Optional: a 100 g calibration weight, such as the A&D 100 g weight for the FX-120i or the A&D 100 g weight with case (not included with the FX-120i).

FX-120i AutoTrickler settings at a glance

Function table item	Set to	What it does (A&D FX-i manual)
bASFnc → SPd (display refresh rate)	2	20 updates per second (0 = 5/s, 1 = 10/s)
dout → Prt (data output mode)	5	Key mode C: outputs when stable, or waits for the stable indicator
SIF → bps (baud rate)	5	19,200 bps
SIF → btPr (data bits, parity)	2	8 bits, no parity (8N1)
RESPONSE (MODE key)	FAST	Fast response; sets Cond 0 and SPd 2

On the scale display, some letters look different: “S” shows as “5” (so SPd reads “5pd”, SIF reads “5if” and bps reads “bp5”).

Step-by-step: A&D FX-120i AutoTrickler setup

1. Install the serial connector. Unplug the scale power cord, plug the AutoTrickler serial port connector into the RS-232C serial port on the FX-120i, and snug the two screws evenly with the included hex key. Then connect the AutoTrickler cable, which carries both power and data.
2. Use the AutoTrickler power adapter. Power the scale with the adapter supplied with the AutoTrickler, not the original A&D adapter. The AutoTrickler manual explains that the original adapter may not reliably power the motors, and the scale can reset when they run.
3. Set the display refresh rate. Press and hold SAMPLE to enter the function table, press SAMPLE until bASFnc appears, press PRINT, press SAMPLE until SPd appears, press RE-ZERO until 2 appears, press PRINT to store it, then press CAL to exit.
4. Set the data output mode. Press and hold SAMPLE to enter the function table, press SAMPLE until dout appears, press PRINT, press SAMPLE until Prt appears, press RE-ZERO until 5 appears, press PRINT to store it, then press CAL to exit.
5. Set the baud rate. Press and hold SAMPLE to enter the function table, press SAMPLE until SIF appears, press PRINT, press SAMPLE until bps appears, press RE-ZERO until 5 appears, press PRINT to store it, then press CAL to exit.
6. Set data bits and parity. Press and hold SAMPLE to enter the function table, press SAMPLE until SIF appears, press PRINT, press SAMPLE until btPr appears, press RE-ZERO until 2 appears, press PRINT to store it, then press CAL to exit.
7. Set the response to FAST. Press and hold MODE until RESPONSE appears, press MODE until FAST is shown, press PRINT, then CAL to exit.
8. Level the scale. Use the two front feet to center the bubble level next to the display.
9. Choose your unit. Press MODE to select grains (GN) or grams (g); the AutoTrickler works in either.
10. Let it warm up. A freshly powered scale can drift for the first few minutes, so you may need to press RE-ZERO a little more often at first.

Do you need to calibrate the FX-120i for the AutoTrickler?

It is optional, but it is the only way to know your charges are accurate. Calibration scales every reading to a known reference mass; it does not change repeatability or drift. The AutoTrickler manual notes that if a 100 g test weight reads within ±0.020 g, powder charges under 100 grains will be accurate within 0.02 grains. Our step-by-step FX-120i calibration guide walks through it with a 100 g weight. See our calibration weights, including the Rice Lake 100 g ASTM Class 1 weight.

Prefer to have it done for you? Mail your FX-120i to us for calibration with a certificate; turnaround is usually 1 to 3 business days:

Troubleshooting the FX-120i and AutoTrickler

• The app connects, but cannot set a target weight: make sure the scale is on and showing a weight in GN or g, then recheck the five settings above. If they look right, reset the scale’s function table to factory settings per the A&D manual and enter the settings again.
• The scale shows “Lb” or resets while the motors run: you are most likely using the original scale adapter. Switch to the power adapter supplied with the AutoTrickler.
• No lights on the AutoTrickler electronics: the AutoTrickler manual says roughly 1% of new A&D FX scales have a serial connector that does not power the electronics. It includes a jumper wire for that case; follow its instructions.
• Readings drift or bounce: keep the scale level and the platform bumpers in place, keep it away from drafts, fans and vibration, and let it warm up after plugging it in.
• Charges are consistently off: check the scale with a 100 g weight and calibrate if needed (see our FX-120i calibration guide), or mail it to us for calibration.

Always verify each charge weight on the scale before loading powder into a case.

Why buy your FX-120i from MNM Scales

MNM Scales is an authorized A&D dealer and one of the largest scale distributors in the country, with over 30 years in business. We stock the FX-120i and the FX-123, 100 g calibration weights, and we calibrate balances in-house with in-house or NIST-traceable certificates. Questions about your setup? Call Call (832) 290-3120.

Frequently asked questions

What settings does the A&D FX-120i need for an AutoTrickler?

Set bASFnc SPd to 2 (20 updates per second), dout Prt to 5 (print when stable), SIF bps to 5 (19,200 baud), SIF btPr to 2 (8 bits, no parity) and RESPONSE to FAST. You only set them once; the scale stores them and still weighs normally.

How do I get into the FX-120i function table?

Press and hold SAMPLE until the function table appears. Press SAMPLE to step through classes, PRINT to open one, SAMPLE to step through items, RE-ZERO to change the value, PRINT to store it and CAL to exit.

Does the AutoTrickler work with the A&D FX-123?

Yes. The FX-123 is a 122 g x 0.001 g A&D scale that reads in grains, and it uses the same AutoTrickler setup steps. Our FX-123 package includes a 100 g calibration weight.

Why does my FX-120i reset when the AutoTrickler motors run?

The usual cause is the power adapter. Power the scale with the adapter supplied with the AutoTrickler instead of the original scale adapter.

Do I have to calibrate my FX-120i before using an AutoTrickler?

It is optional, but recommended. If a 100 g weight reads within 0.020 g, charges under 100 grains will be accurate within 0.02 grains. You can calibrate with a 100 g weight or mail the scale to us for calibration with a certificate.

Which unit should I use, grains or grams?

Either. Press MODE on the scale to select grains (GN) or grams (g); the AutoTrickler supports both.