RFID Readers

13.56 MHz high-frequency RFID readers for AGVs — tags in the floor tell the robot where it is as it drives over them.

• Wiring and first setup
• Using it with an AGV
• Modbus command reference (501 · YP561)
• Own-protocol command reference (401 · YP461)

What it does in an AGV

A robot following magnetic tape or running SLAM knows roughly where it is, but not which place in the building this is. RFID fills that gap.

Use	How
Marking a stop	A tag at the loading point tells the robot it has arrived
Marking a junction	A tag before the junction says turn left or right
Correcting drift	Odometry drifts; reading a tag resets the robot to a known position
Triggering actions	A tag can mean slow down, lift, or switch on a warning light

Tip

RFID is more dependable here than it first appears, because a tag stays exactly where it was installed — unlike a computed position, which drifts further every hour.

Models we supply

Two families, each with two variants that differ in how you command them.

Model	Command interface	Read range
AMR-THS501	Modbus RTU / TCP	0–160 mm
AMR-THS401	Manufacturer’s own protocol	0–160 mm
AMR-YP561	Modbus RTU / TCP	0–100 mm
AMR-YP461	Manufacturer’s own protocol	0–100 mm

Important

Choose Modbus if you are connecting to a PLC or ROS 2. It is an open standard with libraries in nearly every language, and far easier to get help with.

The own-protocol variants suit projects written entirely in-house that want shorter commands.

Danger

🔴 Two models can both speak Modbus and still not be interchangeable.

THS501 and YP561 both use Modbus, but their baud rate code tables are swapped.

Code	THS501	YP561
1	57600	19200
3	19200	57600

Use the wrong table when changing the baud rate and the reader ends up at a speed you did not intend — and stops answering immediately. You then have to try each speed until you find it.

Always read the model code off the label first.

Specifications you need when designing

	Value
Frequency	13.56 MHz
Tag standards	ISO15693 · ISO14443A
Tag speed supported	over 3 m/s
Supply	DC 7.5–36 V · under 250 mW
Size	79 × 79 × 39 mm · 185 g
Environment	IP67 · −20 to +70 °C
Ports	RS232 · RS485 · RJ45 (depending on variant)

Note

Tag speed is not the bottleneck. A factory AGV runs at roughly 0.5–1 m/s, well within what the reader handles.

The real bottleneck is how often your software asks. Poll once a second and a robot at 1 m/s will have driven past the tag before anyone looked.

Test tool

A browser page for testing a reader without writing any code — read tag UIDs, drive the lights and buzzer, set the address and baud rate.

Open the RFID test tool

There is a separate page per model. Pick the one matching the code on your reader.