HUIZHONG SCL-61D Ultrasonic Water Meter Integration

Model catalog

Search for these models in ThinkLink by name or ID.

Model type	Name	id_name	Platform model ID
RPC	[SCL-61D GET] 23111	scl61d_get_23111	110312230444077061
RPC	[SCL-61D SET] 23111	scl61d_set_23111	110312286060548101
Template	SCL-61D		110312390112841733
Thing Model	[SCL-61D]	scl61d_23111	110311140134752261
Thing Model	[HZ-23111-SCL-61D资产] 区域聚合	scl61d_asset_23111	119677189950959619
Parameter Thing Model	[SCL-61D-PARA]	scl61d_para_23111	110311197902901253

This document describes how to connect the HUIZHONG SCL-61D5/6 Ultrasonic Water Meter to the ThinkLink platform via a KC21 data collector using Modbus RTU + EdgeBus protocol. It covers:

Device wiring and communication parameters
ThinkLink platform configuration
Data reporting and third-party subscription
Advanced EB integration (EBHelper / Thing Model / RPC)

Part 1: User Guide

2. Sensor Information (SCL-61D Ultrasonic Water Meter)

2.1 Basic Information

Item	Details
Brand	HUIZHONG (汇中仪表)
Model	SCL-61D5 / SCL-61D6
Device Type	Ultrasonic Water Meter
Power Supply	Internal battery (self-powered, no external power required)

2.2 Communication Parameters (RS485 / Modbus RTU)

Parameter	Value
Protocol	Modbus RTU
Baud Rate	9600 bps
Data Bits	8
Parity	None
Stop Bits	1
Device Address Range	0x01–0xFA
Function Code	0x03 (Read Holding Registers)

2.3 Data Registers

Register Address	Data	Unit	Bytes	Data Type
0x0000–0x0001	Instantaneous Flow	0.001 m³/h	4	Float Inverse (FloatLE)
0x0002–0x0003	Positive Cumulative Flow	0.1 m³	4	Long Inverse (Uint32LE)
0x0004–0x0005	Positive Cumulative Run Time	h	4	Long Inverse (Uint32LE)
0x0006–0x0007	Negative Cumulative Flow	0.1 m³	4	Long Inverse signed (Int32LE)
0x0008–0x0009	Negative Cumulative Run Time	h	4	Long Inverse signed (Int32LE)
0x000A–0x000B	Water Temperature	℃	4	Float Inverse (FloatLE)
0x000C–0x000D	Pressure	0.001 MPa	4	Float Inverse (FloatLE)
0x000E	Meter Information / Diagnostic Code	—	2	Hex

The high byte of Meter Information is fixed at 0x00; the low byte is the diagnostic code (JD). 0x00 = normal. See appendix for details.

2.4 Wiring

KC21 Wire	Connect to Meter
Blue (RS485 A)	RS485 A
White (RS485 B)	RS485 B
Black (GND)	GND

⚠️ Notes:
The SCL-61D has an internal battery — do not connect the KC21 red/brown power wire to the meter
No preamble wake-up required: SCL-61D uses standard Modbus RTU — send query commands directly

3. Collector Information (KC21)

3.1 Basic Information

Item	Details
Model	KC21 (A1 version, 10800 mAh internal battery)
Power Supply	Internal battery
External Power Output	15V (not used in this setup — meter is self-powered)

3.2 KC21 Wiring

Wire Color	Function
Red / Brown	Power + (not connected in this setup)
Black	Power − / GND
Blue	RS485 A
White	RS485 B

4. ThinkLink Platform Configuration

4.1 Adding a Device

Log in to the ThinkLink platform
Navigate to Device Management → Add Device
Search for and select the template HZ-BATTERY-23111
Complete device creation

4.2 Parameter Configuration (Poll Period & Address)

Path: Device Management → Select Device → Configuration → RPC

Select RPC: [EB SET] easy para

Parameter	Meaning	Notes
period	Poll period	Unit: seconds, recommended 900 (15 min)
addr	Meter Modbus address	Factory default 0x01

Changes take effect on the device's next uplink.

4.3 Third-Party Platform Subscription

MQTT Topic

/v32/{Organization Account}/tkl/up/telemetry/{eui}

Sample Payload

json

{
    "eui": "6353012af10a9331",
    "active_time": "2026-05-21T08:00:00.000Z",
    "thingModelId": "scl61d_23111",
    "thingModelIdName": "scl61d_23111",
    "telemetry_data": {
        "snr": 12.5,
        "rssi": -55,
        "battery": 3.6,
        "instant_flow": -1.955,
        "pos_total_flow": 155.2,
        "pos_run_time": 1360,
        "neg_total_flow": -13.1,
        "neg_run_time": 7,
        "temperature": 29.00,
        "pressure": 0.9150,
        "meter_info": 0,
        "update_time": 1747814400000
    }
}

Part 2: Advanced Integration

5. Data Acquisition (EBHelper)

5.1 Protocol Details

Item	Value
Protocol	Modbus RTU
Implementation	EBHelper
BzType	23111
Single Query Range	0x0000–0x000E (15 registers, all data in one request)

5.2 OTA Configuration

javascript

let otaConfig = getOtaConfig({
    BaudRate: 9600,
    StopBits: 1,
    DataBits: 8,
    Checkbit: CheckbitEnum.NONE,
    Battery: true,
    ConfirmDuty: 60,
    BzType: 23111,
    BzVersion: 1
})

5.3 EB Code

typescript

import { Buffer } from "buffer";
import { buildOtaFile } from "@EBSDK/run";
import { EBModel } from "@EBSDK/EBCompiler/EBModel/EBModel";
import { EventInfoItem } from "@EBSDK/EBCompiler/plugins/EBHelper";
import type { UserConfUPItem } from "@EBSDK/EBCompiler/plugins/EBHelper";
import { CheckbitEnum, getOtaConfig } from "@EBSDK/otaConfig";

// SCL-61D5/6 超声水表，Modbus RTU，一次读取 0x0000-0x000E（15个寄存器）
// KC21 电池供电；水表自供电，KC21 不对水表供电
// 无前导码：标准 Modbus RTU，不需要 preamble

const eventInfo: UserConfUPItem[] = [
    {
        name: "water",
        port: 22,
        version: "0x83",
        dataType: "0x32",
        upPeriod: "10y",
        upPeriodIndex: 70,
        quInfo: [
            {
                protocol: "modbus",
                addr: "0x01",
                code: "0x03",
                periodIndex: 70,
                indexAPP: 150, indexCMD: 0, copySize: 1,
                payIndex: 3, ackAddrIndex: 0,
                isLast: true,
                listVal: [
                    { start: "0x0000", end: "0x0001" }, // 瞬时流量 FloatCDAB (FloatLE)
                    { start: "0x0002", end: "0x0003" }, // 正累积流量 UintCDAB (Uint32LE)
                    { start: "0x0004", end: "0x0005" }, // 正累积运行时间 UintCDAB (Uint32LE)
                    { start: "0x0006", end: "0x0007" }, // 负累积流量 IntCDAB (Int32LE)
                    { start: "0x0008", end: "0x0009" }, // 负累积运行时间 IntCDAB (Int32LE)
                    { start: "0x000A", end: "0x000B" }, // 水温 FloatCDAB (FloatLE)
                    { start: "0x000C", end: "0x000D" }, // 压力 FloatCDAB (FloatLE)
                    { start: "0x000E", end: "0x000E" }, // 仪表信息/诊断码 Uint16LE
                ]
            }
        ]
    }
]

let otaConfig = getOtaConfig({
    BaudRate: 9600,
    StopBits: 1,
    DataBits: 8,
    Checkbit: CheckbitEnum.NONE,
    Battery: true,
    ConfirmDuty: 60,
    BzType: 23111,
    BzVersion: 1
})

const MODBUS_TT = (ebModel: EBModel) => {
    for (let i = 0; i < eventInfo.length; i++) {
        let event = new EventInfoItem(eventInfo[i]);
        event.upEventSetup()
        event.eventInstall()
    }
    return JSON.stringify(ebModel, null, 2)
}

buildOtaFile(import.meta.url, otaConfig, MODBUS_TT)

6. Thing Model

6.1 Uplink Frame Layout

Port: 22

EBHelper standard frame (single query: 15 registers × 2 bytes = 30 bytes payload):

Field	Offset	Length (Bytes)	Description
`version`	0	1	Protocol version, fixed 0x83
`dataType`	1	1	Fixed 0x32
`covStatus`	2	1	Reserved
`status`	3	1	Query event status
`battery`	4	1	Battery level
`addr`	5	1	Modbus device address
`instant_flow`	6	4	Instantaneous flow, FloatCDAB
`pos_total_flow`	10	4	Positive cumulative flow, UintCDAB
`pos_run_time`	14	4	Positive run time, UintCDAB
`neg_total_flow`	18	4	Negative cumulative flow, IntCDAB
`neg_run_time`	22	4	Negative run time, IntCDAB
`temperature`	26	4	Water temperature, FloatCDAB
`pressure`	30	4	Pressure, FloatCDAB
`meter_info`	34	2	Diagnostic code, Uint16LE

Total frame length: 36 bytes

6.2 Thing Model Info

Item	Value
Thing Model Name	SCL-61D
ThingModel ID Name	scl61d_23111
Event Name	water

6.3 Field Mapping

Field	Meaning	Unit	Scale
`instant_flow`	Instantaneous flow	m³/h	raw × 0.001
`pos_total_flow`	Positive cumulative flow	m³	raw × 0.1
`pos_run_time`	Positive run time	h	—
`neg_total_flow`	Negative cumulative flow	m³	raw × 0.1
`neg_run_time`	Negative run time	h	—
`temperature`	Water temperature	℃	—
`pressure`	Pressure	MPa	raw × 0.001
`meter_info`	Diagnostic code	—	0x00 = normal
`battery`	KC21 battery level	—	—
`rssi`	Signal strength	dBm	—
`snr`	Signal-to-noise ratio	dB	—

6.4 RPC Parameter Configuration

RPC Name: [EB SET] easy para
ID Name: eb_set_easy_para

Address	Meaning
app_70	Poll period (seconds)
app_150	Meter Modbus address

Appendix: Diagnostic Code Reference (meter_info low byte JD)

Code	Meaning
0x00	Normal
JD & 0x0F = 0x01	Battery voltage below 3.37V — replace battery
JD & 0x0F = 0x02	Empty pipe or transducer fault — no measurement signal
JD & 0x0F = 0x03	Codes 01 and 02 both active
JD & 0x0F = 0x04	Battery voltage below 3.3V — must replace battery immediately
JD & 0x0F = 0x05	Communication fault between calculator and transducer
JD & 0x0F = 0x06	E2PROM failure
JD & 0x10 = 0x10	Supply temperature sensor fault or supply temperature below 2℃
JD & 0x20 = 0x20	Supply temperature exceeds 150℃
JD & 0x40 = 0x40	Return temperature sensor fault or return temperature below 2℃
JD & 0x80 = 0x80	Return temperature exceeds 150℃

Summary

Complete integration path: SCL-61D → KC21 → EdgeBus → ThinkLink
Supports: remote parameter configuration, periodic full-field data collection (8 fields), standard MQTT third-party subscription
Thing Model: scl61d_23111
RPC: eb_set_easy_para
Template: HZ-BATTERY-23111
Low-power, battery-operated design suitable for water metering and pipe network monitoring

LoRaWAN Gateway

Application Notes

LoRaWAN EB Collector

LoRaWAN Sensor

Network Server

Device

meter

BMS

Industry

HUIZHONG SCL-61D Ultrasonic Water Meter Integration

Model catalog

Part 1: User Guide

2. Sensor Information (SCL-61D Ultrasonic Water Meter)

2.1 Basic Information

2.2 Communication Parameters (RS485 / Modbus RTU)

2.3 Data Registers

2.4 Wiring

3. Collector Information (KC21)

3.1 Basic Information

3.2 KC21 Wiring

4. ThinkLink Platform Configuration

4.1 Adding a Device

4.2 Parameter Configuration (Poll Period & Address)

4.3 Third-Party Platform Subscription

MQTT Topic

Sample Payload

Part 2: Advanced Integration

5. Data Acquisition (EBHelper)

5.1 Protocol Details

5.2 OTA Configuration

5.3 EB Code

6. Thing Model

6.1 Uplink Frame Layout

6.2 Thing Model Info

6.3 Field Mapping

6.4 RPC Parameter Configuration

Appendix: Diagnostic Code Reference (meter_info low byte JD)

Summary

LoRaWAN Gateway

Application Notes

LoRaWAN EB Collector

LoRaWAN Sensor

meter

BMS

Industry

HUIZHONG SCL-61D Ultrasonic Water Meter Integration ​

Model catalog ​

Part 1: User Guide ​

2. Sensor Information (SCL-61D Ultrasonic Water Meter) ​

2.1 Basic Information ​

2.2 Communication Parameters (RS485 / Modbus RTU) ​

2.3 Data Registers ​

2.4 Wiring ​

3. Collector Information (KC21) ​

3.1 Basic Information ​

3.2 KC21 Wiring ​

4. ThinkLink Platform Configuration ​

4.1 Adding a Device ​

4.2 Parameter Configuration (Poll Period & Address) ​

4.3 Third-Party Platform Subscription ​

MQTT Topic ​

Sample Payload ​

Part 2: Advanced Integration ​

5. Data Acquisition (EBHelper) ​

5.1 Protocol Details ​

5.2 OTA Configuration ​

5.3 EB Code ​

6. Thing Model ​

6.1 Uplink Frame Layout ​

6.2 Thing Model Info ​

6.3 Field Mapping ​

6.4 RPC Parameter Configuration ​

Appendix: Diagnostic Code Reference (meter_info low byte JD) ​

Summary ​

HUIZHONG SCL-61D Ultrasonic Water Meter Integration

Model catalog

Part 1: User Guide

2. Sensor Information (SCL-61D Ultrasonic Water Meter)

2.1 Basic Information

2.2 Communication Parameters (RS485 / Modbus RTU)

2.3 Data Registers

2.4 Wiring

3. Collector Information (KC21)

3.1 Basic Information

3.2 KC21 Wiring

4. ThinkLink Platform Configuration

4.1 Adding a Device

4.2 Parameter Configuration (Poll Period & Address)

4.3 Third-Party Platform Subscription

MQTT Topic

Sample Payload

Part 2: Advanced Integration

5. Data Acquisition (EBHelper)

5.1 Protocol Details

5.2 OTA Configuration

5.3 EB Code

6. Thing Model

6.1 Uplink Frame Layout

6.2 Thing Model Info

6.3 Field Mapping

6.4 RPC Parameter Configuration

Appendix: Diagnostic Code Reference (meter_info low byte JD)

Summary