What baud rate does the LR1000E2 family use?

115200 bps, 8 data bits, factory default; 9600 bps is selectable.

How is the checksum computed?

Command frames sum bytes 3–7; replies sum bytes 1–7, taking the low 8 bits. The manual states the two ranges separately.

55 AA 8-byte UART frame — E-series and LRF/SPD rangefinders

Transcribed from the manufacturer's own manuals · byte strings verified against the source PDF · no reverse-engineered guesses

One measurement is `55 AA 88 FF FF FF FF 84` at 115200 8N1; the module answers `55 AA 88 STA FF DIS_H DIS_L SUM`. The trap is the checksum: the command frame sums bytes 3–7, the reply sums bytes 1–7.

Frame layout

8 字节帧：Frame Header (H) | Frame Header (L) | Function Code | D1 | D2 | D3 | D4 | Checksum；UART-TTL，默认 115200 bps，8 data bits；发送帧校验 SUM(Function Code + DATA1 + … + DATA4)（原文 SUM[3:7]），应答帧校验 SUM(Frame Header (H)+Frame Header (L)+…+DATA4)（原文 SUM[1:7]），取累加和低 8 位；原文单列 Notes 强调命令帧与应答帧校验范围不同。

Command set

Code	Function	Send	Reply	Notes / page
`0x88`	单次测距 Single-Shot Ranging	`55 AA 88 FF FF FF FF SUM[3:7]`	`55 AA 88 STA FF DIS_H DIS_L SUM[1:7]`	STA = 1: Measurement successful; any other STA value: Measurement failed。DIS_H/DIS_L 为距离高/低字节，原始输出 = 测量值 × 10 · p7
`0x89`	连续测距 Continuous Ranging	`55 AA 89 FF FF FF FF SUM[3:7]`	`55 AA 89 STA FF DIS_H DIS_L SUM[1:7]`	STA = 1 成功，其他值失败；原始输出 = 测量值 × 10 · p7
`0x8E`	停止连续测距 Stop Ranging	`55 AA 8E FF FF FF FF SUM[3:7]`	`55 AA 8E STA FF FF FF SUM[1:7]`	STA = 0: Failed to stop continuous ranging; STA = 1: 停止成功 · p7
`0x8A`	角度测量 Angle Measurement	`55 AA 8A FF FF FF FF SUM[3:7]`	`55 AA 8A STA FF ANG_H ANG_L SUM[1:7]`	STA = 0 失败 / 1 成功；ANG_H/ANG_L 为角度高/低字节，原始输出 = 测量值 × 10；仅带角度传感器的型号可用 · p7
`0x80`	上电自检 Power-On Self-Test（模块主动上报）	`—`	`55 AA 80 STA 00 00 ErrCode SUM[1:7]`	STA = 0: Power-on initialization failed, ErrCode 为错误码；STA = 1: 初始化成功
`TYPE`	波特率设置 Baud Rate	`55 AA TYPE FF FF FF FF SUM[3:7]`	`55 AA TYPE STA FF FF FF SUM[1:7]`	TYPE = 01: 9600 / 02: 14400 / 03: 19200 / 04: 38400 / 05: 56000 / 06: 57600 / 07: 115200 / 08: 128000 / 09: 230400 bps；STA = 0 失败 / 1 成功；重启后生效 · p8
`0x86`	LD 常亮模式 LD Constant-On Mode	`55 AA 86 FF FF FF STA SUM[3:7]`	`55（原文应答行只印出 55，未给出完整应答帧）`	发送侧 STA = 0: Disable LD constant-on mode / 1: Enable；应答侧 STA = 0 已开 / 1 已关 / FF 操作失败；原文强调不得长时间常亮 · p8

Timing and rates

p2 · adaptive measurement rate of 2–10 Hz. The Technical Specifications table lists the operating conditions and p2 · 7 Measurement Rate 2 Hz – 10 Hz Adaptive (higher refresh rates customizable) p2 · 8 Valid Measurement Rate ≥ 98% p2 · 11 Baud Rate 115200 bps p2 · 13 Startup Time ≤ 200 ms p3 · distance measurements on the target. The typical refresh rate is set to 2 Hz or 5 Hz, and the maximum refresh p3 · rate can reach 30 Hz (customized version required). The refresh rate can be adjusted through the serial p6 ·  Baud rate: 115200 bps (default) p7 · Power-On Self-Test p7 · STA = 0: Power-on initialization failed; ErrCode identifies the corresponding error

Status codes and errors

p2 · 9 False Alarm Rate ≤ 1% p7 · STA = 1: Measurement successful; any other STA value: Measurement failed p7 · STA = 0: Failed to stop continuous ranging; STA = 1: Continuous ranging stopped successfully p7 · STA = 0: Measurement failed; STA = 1: Measurement successful p7 · 55 AA 80 STA 00 00 ErrCode SUM[1:7] p7 · STA = 0: Power-on initialization failed; ErrCode identifies the corresponding error p7 · STA = 1: Power-on initialization successful p8 · STA = 0: Setting failed; STA = 1: Setting successful p8 · STA = 0: Disable LD constant-on mode; STA = 1: Enable LD constant-on mode p8 · STA = 0: LD is already on; STA = 1: LD is already off; STA = FF: Operation failed

What the source does not state

Where a manual prints an incomplete reply (for example only 55 for the LD constant-on acknowledgement), this page reproduces that and stops — it does not pad the frame. Anything not printed in the manual is absent here on purpose.

Models covered by this page

Source documents

LR1000E2 · LR1000E2_User_Manual_EN.pdf (9 pages)
LR1000E4 · LR1000E4_User_Manual_EN.pdf (9 pages)
LR1200E2 · LR1200E2_User_Manual_EN.pdf (9 pages)
LR1200E4 · LR1200E4_User_Manual_EN.pdf (9 pages)
LR1500E2 · LR1500E2_User_Manual_EN.pdf (9 pages)
LR1500E4 · LR1500E4_User_Manual_EN.pdf (9 pages)
LR2000E2 · LR2000E2_User_Manual_EN.pdf (9 pages)
LR2000E4 · LR2000E4_User_Manual_EN.pdf (9 pages)
LRF1200A1 · LRF1200A1_User_Manual_EN.pdf (9 pages)
LRF3000A1 · LRF3000A1_User_Manual_EN.pdf (9 pages)

Full transcription method: byte strings are asserted to exist in the extracted PDF text at build time, and re-checked against the page citation. If a string is not in the PDF, the page is not published.

Frequently asked questions

The same answers are published below as visible text and as FAQPage structured data, so the page and the markup cannot drift apart.

What baud rate does the LR1000E2 family use?: 115200 bps, 8 data bits, factory default; 9600 bps is selectable.
How is the checksum computed?: Command frames sum bytes 3–7; replies sum bytes 1–7, taking the low 8 bits. The manual states the two ranges separately.