USB Load Cell: Connect Force Measurement Straight to a PC (A&D LCCU21)

Reviewed by MNM Scales technicians · Updated October 30, 2026 · Prices checked October 30, 2026

Engineers, product designers, labs and QC teams often need to see force on a computer without building a full weighing system. A USB load cell is the shortest path: one cable from the sensor to the PC. MNM Scales has supplied load cells, indicators and complete weighing systems for over 30 years, and we stock the A&D LCCU21 series alongside our standard load cells. This guide explains how USB load cells differ from analog cells, what the LCCU21 can do and how to set it up.

USB load cell vs analog load cell and indicator

Most industrial load cells are analog strain-gauge sensors. They put out a few millivolts per volt of excitation, which an indicator or transmitter turns into a weight reading. A USB load cell moves that electronics into the cable and talks to a computer directly.

	USB load cell (A&D LCCU21)	Analog load cell + indicator
Output	Digital readings over USB 2.0 (micro-B)	mV/V analog signal
Power	USB bus, 5 V, under 50 mA	Excitation from the indicator or amplifier
What else you need	A Windows PC and WinCT-DLC (free) or your own software	Indicator, transmitter or amplifier, plus cabling and often a junction box
Readout	Force in newtons on the PC, up to 100 readings per second	Weight on the indicator display; data via RS-232, USB or Ethernet options
Typical capacity	100 N to 1 kN	From a few pounds to hundreds of thousands of pounds
Best for	Force testing, R&D, QC benches, product testing and teaching	Scales, tanks, hoppers, crane and process weighing
Trade use	Built for force measurement; for selling by weight, use an NTEP scale	NTEP-certified cells and indicators can be built into a legal-for-trade scale

Building a scale rather than measuring force? See our load cell buying guide, the load cell types explainer and the scale indicator buying guide. Comparing a load cell with a force gauge or compression scale? Read compression scale vs force gauge vs load cell.

A&D LCCU21 USB load cell specifications

Specification	LCCU21 series (A&D)
Models and capacity	LCCU21N100: 100 N (10.20 kgf) · LCCU21N200: 200 N (20.39 kgf) · LCCU21N500: 500 N (50.99 kgf) · LCCU21KN001: 1 kN (102.0 kgf), on request
Type	Compact compression (button) load cell with built-in A/D converter and USB interface
Combined error	0.5% R.O. (rated output)
Zero balance	±2% R.O.
Temperature effect	0.6% per 10 °C; compensated 0 to 70 °C; usable -10 to 80 °C
Safe overload	150% of rated capacity
A/D conversion	100 times per second; digital filter off to 11 Hz (1.0 Hz default)
Interface	USB 2.0 Full Speed, micro-B; virtual COM port, 38400 bps, 8 bits, even parity, 1 stop bit, ASCII
Power	USB bus power, DC 5 V, under 50 mA
Protection	IP64 (load cell only)
Cables	2 m load cell cable, 1.5 m USB cable
In the box	Load cell, mounting holder, USB cable and manual (M3 mounting bolts not included)

Specifications are from A&D’s LCCU21 instruction manual and product page. Prices checked October 30, 2026 and may change; the product page shows the current price.

Which capacity do you need?

USB load cells are rated in newtons. Pick the smallest capacity that covers your highest expected force, so you use as much of the range as possible, and keep any shock below the 150% safe overload.

Model	Capacity	kgf	lbf	Price
LCCU21N100	100 N	10.20	22.5	$97.90
LCCU21N200	200 N	20.39	45.0	$97.90
LCCU21N500	500 N	50.99	112.4	$198.00
LCCU21KN001	1 kN (1,000 N)	102.0	224.8	Call for availability

Conversions: 1 N = 0.102 kgf = 0.2248 lbf. A 500 N cell, for example, reads forces up to about 112 lbf. Need more than 1 kN? A&D’s CP-1 compression load cell ($727.91) handles 10 kN, but it is an analog cell and needs an indicator.

How to set up a USB load cell

1. Install the software. Download WinCT-DLC from A&D (free; Windows 7, 8.1 or 10 with .NET Framework 4.5).
2. Connect the USB cable. Use the USB cable supplied with the cell. Windows installs the USB driver automatically; check the COM port number in Device Manager.
3. Mount the cell on a rigid, flat base with the supplied holder (M3 bolts, not included) or with cyanoacrylate adhesive. Do not press on the center of the mesh.
4. Load it straight. Apply force vertically through a rigid surface. Side loads and off-center loads reduce accuracy and can damage the cell.
5. Ground it. Keep the load cell at the same electrical potential as the PC to avoid noise.
6. Zero and start logging. In WinCT-DLC, select the COM port, zero the reading with no load, then log single values or a continuous stream.

What WinCT-DLC does

• Zero offset, tare, peak hold and bottom hold.
• Single or continuous logging at up to 100 readings per second (10 per second by default).
• Saves about 1 million points to Excel (split into files of 300,000) or longer runs to CSV.
• Reads several cells at once through USB hubs, so you can see how a load is shared.

Want to send weight from a regular scale to a PC instead? See how to connect a scale to a computer with USB or RS-232.

What people measure with a USB load cell

Typical small-force jobs, most of them from A&D’s own application examples:

• Crush force of plastic bottles and packaging.
• Pressing force in assembly and press-fit work.
• Grip strength needed to open a jar lid.
• Load distribution across the legs of a bed or the frame of a drone.
• Force on rehabilitation and fitness equipment.
• Press force on switches, buttons and latches in product testing.

USB load cell buying checklist

• ☐ Your highest force is within the capacity, with any shock below 150%.
• ☐ The force is compression, applied straight down through a rigid surface.
• ☐ A Windows PC for WinCT-DLC, or software of your own that reads a COM port.
• ☐ A rigid, flat mounting base and M3 bolts for the holder (not included).
• ☐ 0.5% R.O. combined error is enough for your test; for weighing goods for sale, use an NTEP bench scale instead.
• ☐ Several cells? Plan the USB hub and one cable run per cell.

Support, testing and quotes

Load cells are quoted individually, including calibration certificates, other capacities and the 1 kN LCCU21KN001. Tell us the force range, mounting and the certificate you need and we will quote it. If a load cell on an existing scale or system is acting up, our load cell testing guide walks through the checks, and we repair the scales and systems we sell and rent all types of scales.

USB load cell FAQ

What is a USB load cell?

A USB load cell is a force sensor with the amplifier, A/D converter and USB interface built in. It plugs straight into a computer, takes its power from the USB port and sends force readings in newtons, so you do not need a separate indicator or amplifier. The A&D LCCU21 series is a compact compression (button) USB load cell from 100 N to 1 kN.

Do I need an amplifier or indicator with a USB load cell?

No. The A&D LCCU21 converts the signal inside the cable electronics and sends digital data over USB, powered by the USB bus (5 V, under 50 mA). A standard analog load cell outputs millivolts and does need an indicator, transmitter or amplifier.

What software works with the A&D LCCU21?

A&D’s free WinCT-DLC software for Windows reads up to 100 values per second, with zero offset, peak hold, bottom hold, tare and logging to Excel or CSV. The cell appears as a virtual COM port and sends ASCII data at 38400 bps, 8 bits, even parity, 1 stop bit, so your own software can read it too.

How accurate is the A&D LCCU21 USB load cell?

A&D rates the combined error at 0.5% of rated output, so about 0.5 N on the 100 N model and 2.5 N on the 500 N model, with a temperature effect of 0.6% per 10 °C. It is built for force testing and monitoring; for weighing goods for sale, choose an NTEP scale.

Which USB load cell capacity should I choose?

Pick the smallest capacity that covers your highest expected force: 100 N (about 22.5 lbf), 200 N (about 45 lbf), 500 N (about 112 lbf) or 1 kN (about 225 lbf). The safe overload is 150% of capacity, so keep shocks and impacts below that.

Can I connect more than one USB load cell to a PC?

Yes. WinCT-DLC can read several LCCU21 load cells at once through USB hubs, which is useful for checking how a load is shared, for example across the legs of a bed or a drone frame.

Can MNM Scales supply a calibration certificate for a USB load cell?

Load cells and force-measurement setups are quoted individually. Call (832) 290-3120 or request a quote with the model, capacity and the certificate you need.