A&D EJ-6100 Manual, Explained: Keys, Units, Counting, Comparator, Calibration and RS-232C

By MNM Scales · Last updated October 31, 2026

The A&D EJ-6100 is the largest model in A&D’s Newton EJ series: 6,100 g by 0.1 g on a 127 x 140 mm pan, running on AC or batteries. One manual covers ten EJ balances, from the 120 g EJ-120 to the EJ-6100, so it mixes notes for 0.01 g and 0.1 g models and for accessories that fit only some of them. This guide keeps only what applies to the EJ-6100, with the display codes as they appear on the balance. The newer EJ-123, EJ-303, EJ-1202, EJ-3002 and EJ-54D2 have their own manual (see our reloading scale comparison for the EJ-54D2).

EJ-6100 specifications from the manual

Item	EJ-6100
Capacity x readability	6,100 g x 0.1 g
Repeatability (standard deviation)	0.1 g
Linearity	±0.3 g
Calibration weight (factory setting)	6,000 g (not included); the value can be changed
Counting	Samples of 5, 10, 25, 50 or 100 pieces; up to 61,000 pieces; minimum unit weight 0.1 g
Percent mode	Minimum reference weight 10 g; displays to 0.1 percent
Other units (capacity x readability)	oz 215.17 x 0.01 · lb 13.448 x 0.001 · ozt 196.12 x 0.01 · dwt 3,922.4 x 0.1 · grain 94,138 x 2 · momme 1,626.65 x 0.05
Display	7-segment LCD with backlight, 16 mm characters, updates 10 times per second
Power	AC adapter, or 4 AA batteries (not included) for about 70 hours with the backlight off
Operating range	-10 to 40 °C (14 to 104 °F), below 85 percent RH, non-condensing
Pan and weight	127 x 140 mm pan; balance about 1,070 g

Setting up the EJ-6100

1. Fit the pan on the main unit.
2. Choose the spot. A firm bench away from dust, drafts, vibration, large temperature swings, condensation, magnetic fields, direct sun, heaters and air conditioners.
3. Level it. Turn the leveling feet until the bubble in the spirit level sits in the center of the circle.
4. Power it. Plug the AC adapter into the jack on the back, or slide off the battery cover, pull out the battery box and fit 4 AA (LR6) batteries, watching the polarity. Replace all four when lb0 shows. A spare TB-662 AC adapter is sold separately.
5. Warm it up. A&D asks for the power to be on for at least half an hour before use.
6. Calibrate when you first set it up and every time you move it (see below).

At power-on the EJ-6100 shows all its indicators, then shows zero with the ZERO indicator once the reading is steady. To have it turn itself off after about 5 minutes at zero, set poff 1 in the function table.

The keys and the CAL switch

Key	In weighing	In settings
ON:OFF	Turns the balance on or off	Cancels and turns the balance off
RE-ZERO	Zero and tare in one key: zeroes small drift, subtracts a container as tare	Changes the blinking digit or the parameter
UNITS	Steps through the stored units, pcs and percent	Cancels and moves on, or returns to weighing
SAMPLE	In pcs or percent, enters sample or reference storing; hold it to open the function table (func)	Selects the class, item or digit
PRINT	Sends the reading to a printer or PC; hold it to start or end a GLP title block	Stores the setting (Enter)
CAL switch (under the cover on the bottom)	Hold until Cal shows to calibrate; keep holding to CC for a calibration test	–

Units: store only the ones you use

The EJ-6100 can show grams, ounces, pounds, troy ounces, carats, momme, pennyweight, grains, newtons, density (specific gravity), pieces and percent. Which ones appear was set at the factory; you choose from those.

1. Hold SAMPLE until func appears, then press SAMPLE until Unit appears and press PRINT.
2. Press SAMPLE to show each unit, and RE-ZERO to select it (the STABLE indicator marks a selected unit).
3. Press PRINT to store the set, then UNITS to go back to weighing. The first unit you selected becomes the one shown at power-on.

For grain, carat and troy-ounce math, our grain to gram converter does the conversions.

Counting with ACAI, percent and the comparator

Counting (pcs)

1. Press UNITS until pcs shows, then press SAMPLE.
2. Press SAMPLE again to pick 5, 10, 25, 50 or 100 samples.
3. Tare a container with RE-ZERO, put the chosen number of pieces on the pan and press PRINT to store the unit weight.
4. Add the parts to count. With ACAI on, adding a few more pieces (three or more) makes the ACAI indicator blink while the balance refines the unit weight; leave the pan alone until it stops.

If the pieces are too light, the balance asks for a bigger sample (25 -, 50 -, 100 -) or shows lo. On the EJ-6100 the minimum unit weight is 0.1 g with the factory Umin 0 setting. For small parts, a 0.01 g balance counts more reliably; see our counting scale buying guide.

Percent

Press UNITS until the percent unit shows, press SAMPLE, then RE-ZERO, place the reference (at least 10 g) and press PRINT. Each sample then reads as a percentage of that reference, to 0.1 percent.

Comparator: HI, OK and LO

The comparator checks every reading against an upper and lower limit and shows HI, OK or LO. Hold SAMPLE to func, press PRINT, step with SAMPLE to Cp and choose a condition with RE-ZERO:

• Cp 0 off · Cp 1 all data · Cp 2 all stable data
• Cp 3 plus data above +4 divisions · Cp 4 stable plus data above +4 divisions
• Cp 5 data above +4 or below -4 divisions · Cp 6 stable data above +4 or below -4 divisions

Press PRINT to store it, then enter the limits at Cp Hi and Cp lo (SAMPLE moves the digit, RE-ZERO changes it, PRINT stores). The limits are shared by grams, pieces and percent.

Function table settings

Hold SAMPLE until func shows, press PRINT, then SAMPLE moves to the next item, RE-ZERO changes the value and PRINT stores the class. UNITS returns to weighing. Factory settings are marked with an asterisk.

Item	Settings	What it does
poff Auto power-off	0* off · 1 on	Turns off after about 5 minutes at zero
Cond Response	0 fast to 4 slow (2*)	Higher is steadier on a busy bench
st-b Stability band	0 = 0.5d · 1* = 1d · 2 = 2d	When the STABLE indicator lights
trc Zero tracking	0 off · 1* on	Holds zero against slow drift
pnt Decimal point	0* point · 1 comma	Separator on display and output
Cp Comparator	0* to 6	See the comparator section
prt Data output mode	0 stream · 1* PRINT key · 2 auto-print A · 3 auto-print B · 4 command only	When data goes out the interface
pUse Output pause	0* none · 1 = 1.6 s	Spacing for continuous output
info GLP output	0* none · 1 AD-8121 printer · 2 general (PC)	Adds calibration and test reports
bps Baud rate	0 = 2400* · 1 = 4800 · 2 = 9600 · 3 = 1200	Must match the printer or PC
btpr Data bits and parity	0* 7 bits even · 1 7 bits odd · 2 8 bits none	Must match the printer or PC
aCai ACAI	0 off · 1* on	Refines the unit weight while counting
Umin Minimum unit weight	0* = 1d · 1 = 1/10 d · 2 = sample total of 5d or more	Smallest piece the counter accepts
smpl First sample number	0* 10 · 1 = 25 · 2 = 50 · 3 = 100 · 4 = 5	Starting sample size in pcs mode
ltUp Backlight	0 off · 1 to 4 off after 5, 10, 30* or 60 s · 5 always on	Battery life versus visibility

Calibrating the EJ-6100

The EJ-6100 calibrates with an external weight. Its stored calibration value is 6,000 g, and you can change it if you calibrate with a different weight. Use a weight of the right class for a 0.1 g balance (see calibration weight classes); calibration weights are not included.

1. Warm the balance up for at least half an hour with nothing on the pan.
2. Press and hold the CAL switch under the cover on the bottom until Cal appears, then release. The display shows Cal 0.
3. To change the weight value, press SAMPLE, set the digits (SAMPLE moves, RE-ZERO changes) and press PRINT.
4. With Cal 0 showing and the pan empty, press PRINT to weigh zero. Do not touch the pan.
5. When the weight value shows, place that weight on the pan and press PRINT.
6. end appears. Remove the weight and press UNITS or the CAL switch to return to weighing. With GLP output on, glp shows while the calibration report prints.

If you move the balance and have no weight on hand, A&D’s gravity acceleration correction (RE-ZERO at Cal 0) sets the local gravity value from the map at the back of the manual. A calibration with a weight on site makes it unnecessary.

To check accuracy without changing the calibration, hold the CAL switch past Cal until CC shows (or hold SAMPLE and PRINT together), weigh zero, then the target weight. With info 1 or info 2 set, the balance outputs a calibration test report.

Cal e means the weight was too heavy for the stored value and -Cal e too light; check the pan and the weight value. If the reading drifts after calibration, see scale will not zero or keeps drifting.

EJ-02 USB and EJ-03 RS-232C interfaces

The EJ-6100 has one option slot on the back, so it takes either the USB or the RS-232C interface, not both. Turn the balance off, press the slot cover down, plug the interface into the connector inside and secure it with its screws.

• EJ-02 USB (not included): sends the weight value one way into Excel, Word or Notepad on a PC with no driver. It cannot receive commands.
• EJ-03 RS-232C (not included; EJ-03C comes with a cable): connects a printer or PC through a straight 9-pin D-Sub cable. The balance is DCE: pin 2 transmit, pin 3 receive, pin 5 ground, 6 DSR, 7 RTS, 8 CTS.

Over RS-232C the balance answers three commands: Q sends the current reading, Z zeroes or tares, and U changes the unit. Data lines start with ST (stable), QT (stable count), US (unstable) or OL (over range), followed by the value and unit, and end in CR LF. Set prt, bps and btpr to match the other end. For cabling and software, see how to connect a scale to a computer.

For GLP records, set an ID number under id in the function table; the calibration and test reports then carry the maker, model, serial number and ID. Holding PRINT starts and ends a title block around a series of weights.

Under-hook weighing

The EJ-07 under-hook (not included) is the one made for the EJ-3000, EJ-4100 and EJ-6100. Remove the cap under the balance and screw in the hook to weigh large items or to set up density work below the balance. Calibrate with the weight hung from the hook for accurate below-balance readings, and refit the cap when the hook is off. The EJ-13 density kit fits only the 0.01 g EJ models.

EJ-6100 error codes

Display	Meaning	What to do
eeeeee	Overload	Remove the load; it is above 6,100 g
--e	Range over notice: strong upward force on the sensor	Check for anything caught around the pan; if it stays, the sensor may need service
lo	Sample too light for a unit weight or percent reference	Use more pieces or a heavier reference
Cal e / -Cal e	Calibration weight too heavy / too light	Check the pan and the calibration value
lb0 / Hb0	Batteries exhausted / battery voltage too high	Fit four new batteries or use the adapter
Hb1 / lb1	Adapter voltage too high / too low	Check that the adapter is the correct type
error1	Reading will not settle	Stop vibration and drafts, then press UNITS

Load cells can fail after heavy use or a shock load, and a cut adapter or interface cable stops power or data. If an error will not clear, our repair bench can help; codes for other brands are in our scale error codes guide.

Selling by weight

The EJ-6100 is not NTEP. It is built for general weighing, counting, kitting, lab and shop work, and its grams, troy ounces, pennyweights and carats suit testing and inventory. For buying or selling precious metals by weight, choose a Class II model such as the A&D EK-1200i (1,200 g x 0.1 g) or the A&D FX-200iN. Our legal for trade jewelry scale guide and EK-1200i vs EK-610i explain the Class II options.

Texas note: TDA does not require an NTEP certificate for every device, but the scale must meet NIST Handbook 44 and suit its use; some scales do need one, so we recommend NTEP models and can check yours. See TDA’s scales used in trade guidance (PDF) and our TDA scale certification guide, or call us or TDA to confirm your use.

Not sure your use counts as trade? Try our free legal-for-trade scale checker.

Care and storage

Clean with a lint-free cloth dampened with warm water and mild detergent; no organic solvents. Ship it in the original packing. EJ balances can be stacked for storage, no more than four high. Remove the batteries if it will sit unused for a long time. Same-size alternatives in the series are the EJ-3000 (3,100 g) and EJ-4100 (4,100 g), which use this same manual; see all A&D precision balances.

Calibration, repair and rentals

• Calibrated before it ships: in-house calibration $195 or NIST calibration certificate $495 for balances from 2.2 to 6.2 kg, including the EJ-6100. See NIST vs in-house certificates.
• Mail-in calibration: pack the balance in its original packing, as A&D recommends, and ship it to our shop with the mail-in calibration service.
• Cypress pickup by appointment: drop off or pick up at our Cypress, TX shop (21249 FM 529 Rd, Cypress, TX 77433).
• On-site service: on-site calibration is $295 plus $2 per mile per visit, plus the calibration fee for each scale. See balance calibration in Houston.
• Repair: load cell, cable, adapter and keypad problems go to our scale repair bench.
• Rentals: we rent all types of scales; ask about a scale rental while yours is in for service.

Frequently asked questions

Where can I find the A&D EJ-6100 manual?

A&D publishes the EJ series instruction manual (1WMPD4001917D) on its Newton EJ series page. One manual covers the EJ-120 through the EJ-6100.

How do I calibrate the A&D EJ-6100?

Warm it up for half an hour, hold the CAL switch under the bottom cover until Cal shows, press PRINT to weigh zero with the pan empty, place the 6,000 g weight (or the value you set) and press PRINT. When end shows, remove the weight.

What calibration weight does the EJ-6100 use?

The factory value is 6,000 g. You can change the stored value from the Cal 0 screen with the SAMPLE key. Weights are not included.

Where is the CAL switch on the EJ-6100?

Under a cover on the bottom of the balance. Hold it to start calibration (Cal) or keep holding for a calibration test (CC).

Can the EJ-6100 connect to a computer?

Yes, with one interface in its option slot: the EJ-02 USB sends readings straight into Excel or Notepad, and the EJ-03 RS-232C connects a printer or PC and accepts the Q, Z and U commands. Interfaces are not included.

What does lo mean on an A&D EJ balance?

The sample is too light to store a unit weight in counting mode or a reference in percent mode. Use more pieces or a heavier reference.

How long do the batteries last in the EJ-6100?

About 70 hours on 4 AA alkaline batteries with the backlight off. Batteries are not included; the balance also runs on its AC adapter.

Is the EJ-6100 legal for trade?

The EJ-6100 is not NTEP. For buying or selling precious metals by weight, choose a Class II model such as the A&D EK-1200i or FX-200iN.