GW-LS-RA1 60GHz Radar Level Sensor Guide

Version	Update Content	Date
V1.0	Initial version	2021‑03‑10
V1.1	1. Optimized product model and mechanical structure; 2. Adjusted partial registers	2025‑02‑28

1. Product Overview

The GW‑LS‑RA1 is a low‑power, high‑accuracy radar level gauge featuring ultra‑compact form factor and wide power‑supply range. With highly‑integrated design, it incorporates a millimeter‑wave radar and high‑gain horn antenna. Its overall ingress protection rating reaches IP67, making it suitable for field operating environments.

Equipped with an RS485 interface, the sensor supports standard Modbus protocol, and custom non‑standard protocols are available upon request. It can be applied to water conservancy & hydrology, sewage treatment, smart agriculture, object detection and many other scenarios.

2. Technical Specifications

Basic Parameters

Item	Parameter	Remarks
Product Model	GW‑LS‑RA1
Supply Voltage	7~28 VDC
Operating Current	Average: 18 mA; Peak: 40 mA
Ingress Protection	IP67
Overall Dimension	Φ54 × 60 mm
Operating Temperature	-40~80 ℃
Operating Humidity	0~100 % RH (non‑condensing)
Zero Reference Line	Bottom of housing serves as zero‑position line

Measurement Parameters

Item	Parameter	Remarks
Measuring Range	0.25‑10 m	Default dead‑zone: 0.25 m
Measurement Accuracy	±5 mm	Measured on hard metallic reflecting surface
Radar Frequency	60 GHz
Antenna Beam Angle	20°

Communication Parameters

Item	Parameter	Remarks
Physical Interface	RS485	Baud rate: 9600
Communication Protocol	MODBUS	Custom non‑standard protocols supported

3. Power‑Supply Instructions

The device accepts input voltage from 7 V to 28 VDC and supports common DC power sources. A linear power supply is implemented internally; operating current is independent of supply voltage. Lower supply voltage yields lower overall power consumption.

For battery‑powered low‑power applications, it is recommended that the main controller controls device power‑on and cuts off module power after data acquisition to reduce total power consumption.

4. Operating Characteristics

Factory‑default parameters are configured for static level measurement and intended for scenarios with slowly‑changing target positions. When the target position changes abruptly, a certain time is required for output to synchronize with the latest position. Faster response can be achieved by modifying configuration parameters, which must be specified before shipment. Higher response speed will degrade measurement accuracy to some extent.

The device responds to Modbus commands immediately after power‑on; nevertheless internal radar data requires time to stabilize with a typical settling time of 5 seconds. For main controllers with low‑power logic, read radar data 5 seconds after power‑on to obtain valid readings.

By default the radar is tuned for slowly‑varying measurands such as water level. When target distance changes abruptly — for example when the radar is re‑oriented from ground toward ceiling or an object is placed beneath the radar — internal algorithms require considerably longer time (typically 30 seconds) to lock onto the new level value, much longer than the power‑on settling time. During testing, power‑cycling the device enables fast acquisition of valid readings after changing target conditions.

For applications requiring fast response to rapidly‑moving targets, notify us prior to shipment and negotiate response‑time requirements.

The unit internally evaluates radar echo strength. Level readings are discarded when echo strength falls below the configured threshold. Insufficient echo strength rarely occurs under normal operating conditions. The main controller may obtain real‑time echo‑strength values via Modbus for on‑site installation diagnosis.

Raw radar output represents empty‑height: distance from mounting point to target object. The device can output raw empty‑height or calculated level value. After writing the mounting reference value to the level register, output equals reference value minus empty‑height, i.e. the level value.

Output level values are always non‑negative:

• When reference value = 0: raw empty‑height is output directly.
• When reference value > empty‑height: output = reference value − empty‑height.
• When reference value < empty‑height: output = 0.

5. Protocol Description

Factory communication settings: baud rate 9600, 8 data bits, 1 stop bit, no parity; Modbus‑RTU protocol. Custom non‑standard protocols can be implemented for drop‑in replacement without modifying main‑controller logic.

5.1 Device Address

• Default device address: 1; configurable via commands.
• If the device address is forgotten, read data using address 0 to identify the actual address.
• When using address 0, ensure only one device is connected on the bus.

5.2 Register Map

Parameter	Register Address	Data Type	Function Code	Description	Default Value
Level Data	0x0000	uint16 (Read‑Only)	03	Unit: mm	0
Device Address	0x03E8	uint16 (Read‑Write)	03/06	1‑254	1
Lower Range Limit	0x001E	uint16 (Read‑Write)	03/16
Upper Range Limit	0x001F	uint16 (Read‑Write)	03/16
Internal Zero Point	0x002E	uint16 (Read‑Only)	03	Unit: mm
Target Value	0x002F	uint16 (Read‑Write)	03/06	Unit: mm
Reference Setting	0x0030	uint16 (Read‑Write)	03/06	Unit: mm	0

5.3 Communication Examples

Read Level Data (level value: 2000 mm)

Transmit	01 03 00 00 00 01 84 0A
Response	01 03 02 07 D0 BB E8

Modify Device Address (from 01 to 02)

Transmit	01 06 03 E8 00 02 88 7B
Response	01 06 03 E8 00 02 88 7B

5.4 Parameter‑Configuration Example

You may view data and configure parameters with any serial‑port debugging tool using commands described in preceding sections. Operation via the visual tool Gewu Online Tool is recommended; no deep understanding of underlying Modbus frame format is required.

1. Select official template: GW‑LS‑RA1 Radar Water‑Level Gauge.
2. Serial‑port parameters: 9600‑8‑N‑1.
3. Click Connect Serial Port and select the serial‑port adapter connected to your computer.
4. Click Start Polling.
5. To write parameters, navigate to the corresponding register, enter the value and click Confirm Write.

Reference‑value modification example: Current empty‑height reading = 1022 mm. Set reference value to 5000 mm; output = 5000 − 1022 = 3978 mm. Reference register address: 0x0030 (decimal 48). Write value 5000 using function code 06.

Device‑address modification: while connected, write target address to register 0X03E8 (decimal 1000). After address change, re‑configure and reconnect within Gewu Online Tool.

6. Wire Harness Definition

Wire Color	Signal
Brown	VCC
Black	GND
Yellow	RS485+
Blue	RS485‑

7. Mechanical Dimensions

Main‑body dimension: Φ54 × 60 mm

Reference mounting method:

8. Packing List

No.	Item	Remarks
1	Sensor Main Unit
2	Auxiliary Mounting Bracket
3	Power‑and‑Signal Cable

Note: Printed user manual is not supplied by default. Contact the manufacturer if a hard copy is required.

9. Precautions

Nominal measuring range of the sensor is 0.25‑12 m. Two out‑of‑range conditions may occur in field use: empty‑height less than dead‑zone; empty‑height greater than 12 m (symptoms identical to loss of valid echo, e.g. non‑vertical installation, non‑water or poor‑reflectivity target surface).

Most acquisition devices output 0 or 0xFFFF upon measurement failure. To differentiate measurement failure from out‑of‑range status, this sensor does NOT use 0 or 0xFFFF to indicate faults.

1. Below dead‑zone (<0.25 m): Positive output value smaller than 0.25 m, which is invalid. This condition only occurs when the sensor is submerged; it will not appear for overhead installation.
2. No valid echo (>12 m, angular misalignment, poor reflector): Negative output value. Represented as a large unsigned 16‑bit Modbus register value (near 65510), indicating invalid measurement.

Rules for host‑side judgement:

• 0.25 m ~ 12 m: valid measurement
• Positive value <0.25 m: within dead‑zone; reading invalid
• Negative value / unsigned value equivalent to >12 m: measurement invalid; adjust mounting angle or installation position.