1. Introduction to the Sensor

Model catalog

Search for these models in ThinkLink by name or ID.

Model type	Name	id_name	Platform model ID
RPC	[SJ101CX GET] para	sj101cx_21307_get	88308771574517765
RPC	[SJ101CX SET] para	sj101cx_21307_set	88308422692311045
Template	SJ101CX		88309182834413573
Thing Model	[SJ101CX]	sj101cx_21307	88304368717139973
Thing Model	[SJ-21307-SJ101CX资产] 区域聚合	sj101cx_asset_21307	119677174411063302

The SJ-101CX is a digital weighing transmitter module developed by Sanjiang Weighing Instruments. It amplifies, processes, and converts analog signals from load cells into digital weight data, which is then output via an RS485 interface. It is suitable for integration with weighing platforms, hopper scales, industrial weighing systems, and similar applications.

This document targets integration scenarios involving ThinkLink + EdgeBus. It consolidates hardware specifications, register definitions, EdgeBus configuration, ThinkLink Thing Model , and RPC configurations—enabling direct platform onboarding and device provisioning.

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2. Key Features

• RS485 interface
• Compliant with standard Modbus-RTU protocol
• Default serial port parameters: 9600 baud, 8 data bits, no parity, 1 stop bit (8N1)
• Supports reading weight value, precision level, and device status
• Supports configuration of parameters such as slave address and baud rate
• Enables rapid onboarding to the ThinkLink platform via EdgeBus

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3. Applicable Scenarios

• Industrial weighing data acquisition
• Platform scale and hopper scale data collection
• Wireless weighing data acquisition systems
• LoRaWAN-based edge data acquisition and cloud platform integration

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4. Integration Specifications

4.1 Hardware Information

• Product Documentation: SJ101CX_V1.02.pdf
• Device Model: SJ-101CX
• Communication Interface: RS485
• Communication Protocol: Modbus-RTU
• Default RS485 Slave Address: 0x01 (configurable via DIP switches)
• Default Baud Rate: 9600
• Serial Format: 8N1
• Power Supply: DC 12–24 V can supplied by KC21
• Operating Temperature: 0–40 °C
• Storage & Transportation Temperature: −25–55 °C

4.2 Wiring Diagram

Power & Communication Interface

• V+: Positive power supply
• V−: Negative power supply
• A+: RS485 A (non-inverting signal line)
• B−: RS485 B (inverting signal line)

Load Cell Interface

• E+: Load cell excitation voltage positive
• E−: Load cell excitation voltage negative
• S+: Load cell signal positive
• S−: Load cell signal negative
• SH: Shield ground wire

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5. Data Acquisition

In this solution, the following Modbus registers are read:

• 0x0000–0x0001: Weight value
• 0x0002–0x0003: Precision and status

5.1 Register Definitions

Access	Register Address	Function	Data Type	Description
Read-only	0x0000–0x0001	Current weight value	32-bit signed integer	Raw weight value
Read-only	0x0002	Precision setting	16-bit unsigned integer	Precision level: 0=1, 1=0.1, 2=0.01, 3=0.001
Read-only	0x0003	Status word	16-bit unsigned integer	Status bits bit0–bit5
Write-only	0x0004	Zero calibration trigger	16-bit unsigned integer	Write 1 to execute zeroing
Read/Write	0x0009	Baud rate	16-bit unsigned integer	0:9600, 1:14400, 2:19200, 3:38400, 4:115200
Read/Write	0x000B	Slave address	16-bit unsigned integer	Range: 1–99; default: 1
Write-only	0x000C	Apply communication settings	16-bit unsigned integer	Write 1 to activate new settings
Read/Write	0x001B	ADC sampling rate	16-bit unsigned integer	0:10 Hz, 1:40 Hz
Write-only	0x003A	Save user configuration	16-bit unsigned integer	Write 1 to persist current settings
Read-only	0x003B	Firmware version	16-bit unsigned integer	Firmware version number

5.2 Status Bit Definitions

Bit	Meaning	Value 0	Value 1
bit0	Weighing stability	unstable	stable
bit1	Zero-point status	non-zero	zero
bit2	Overload status	normal	overload
bit3	Keypress event	no key pressed	key triggered
bit4	Power-on zero calibration	has zero point	no zero point
bit5	Weighing validity	invalid	valid

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6. EdgeBus Model

6.1 EdgeBus Configuration Parameters

Parameter	Value
bzType	21307
Battery	true
Uplink Port	22
version	0x85
dataType	0x04
Default Modbus Slave Address	0x01
Modbus Function Code	0x03
Reporting Interval	Application address 70
Sampling Interval	Application address 74
Weight COV Threshold	Application address 110
Slave Address Parameter	Application address 150

6.2 EdgeBus Configuration Code

import { Buffer } from "buffer";
import { buildOtaFile } from "@EBSDK/run";
import {
    ActionAfertExpr, CalcData,
    CrcMode,
    CvtRule,
    EBBuffer,
    EBModel,
    ExprCondition,
    LoraUpEvent,
    QueryEvent, SetUpCovDataType,
    UserConfUPItem,EventInfoItem
} from "@EBSDK/EBCompiler/all_variable";
import { CheckbitEnum, getOtaConfig, HwTypeEnum, UpgrdTypeEnum } from "@EBSDK/otaConfig";
////////////////////////////////////////////////////////////////////////////////////////
const eventInfo:UserConfUPItem[]=[
    {
        name:"sj101cx",port:21,version:"0x85",dataType:"0x04",upPeriodIndex:70,
        quInfo:[
            {
            protocol:"modbus",addr:"0x02",code:"0x03", periodIndex:74,
            indexAPP:150, indexCMD:0, copySize:1,isLast:false,//period:"900s",payIndex:3,ackAddrIndex:0,
            listVal:[
                { start: "0", end: "1" ,covType:"Uint32BE",covAppIndex:110}, //cov:true,covAppIndex:
                { start: "2", end: "3" } //cov:false,covAppIndex:0
                ]
            }
        ]
    }
]
let otaConfig = getOtaConfig({
    SwVersion:31,
    BaudRate: 9600,
    StopBits: 1,
    DataBits: 8,
    Checkbit: CheckbitEnum.NONE,
    Battery: true,
    ConfirmDuty: 60,
    BzType: 21307,
    BzVersion: 11
})
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)

6.3 Explanation

Current EdgeBus logic summary:

• Uses default slave address 0x01
• Reads registers 0x0000–0x0003
• Interprets 0x0000–0x0001 as a 32-bit big-endian signed integer (weight)
• Interprets 0x0002–0x0003 as separate 16-bit fields (precision and status)
• Weight supports Change-of-Value (COV); reporting threshold uses app_110
• Reporting interval uses app_70
• Sampling interval uses app_74
• Slave address parameter maps to app_150

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7. Thing Model

7.1 Basic Thing Model Information

• Thing Model Name: sj101cx_21307
• Thing Model ID: 88304368717139973

7.2 Uplink Frame Structure

• Port Number: 22
• version: 0x85
• dataType: 0x04

Field Name	Offset (bytes)	Length (bytes)	Data Type	Description
version	0	1	Uint8	Protocol version; fixed value 0x85
dataType	1	1	Uint8	Fixed value 0x04
covStatus	2	1	Uint8	Reserved byte
status	3	1	Uint8	Query event status
battery	4	1	Uint8	Battery voltage (V)
addr	5	1	Uint8	Sub-device Modbus slave address
weight	6	4	Int32BE	Weight value (raw, scaled later)
precision	10	2	Uint16BE	Precision multiplier
statusBits	12	2	Uint16BE	Status bitfield

7.3 Refined Thing Model Script

let port = msg?.userdata?.port || null;

let frameInfo = {
    port: 22,
    dataLen: -1,
    rssi: true,
    battery: 4,
    tagList: [
        { index: 0, tag: 0x85 },
        { index: 1, tag: 0x04 }
    ]
};

let appInfo = [
    {
        name: "weight",
        field_name: "weight",
        unit: "kg",
        index: 6,
        dataType: "int32BE",
        coefficient: "precision",
        decimal: 2,
        illegal: "=00000000"
    },
    {
        name: "precision",
        field_name: "precision",
        unit: "",
        index: 10,
        coefficient: 1,
        dataType: "uint16BE",
        optionList: {
            0: 1,
            1: 0.1,
            2: 0.01,
            3: 0.001
        }
    },
    {
        name: "status1",
        field_name: "status1",
        unit: "",
        index: 12,
        coefficient: 1,
        dataType: "bitBE0-0",
        optionList: {
            0: "unstable",
            1: "stable"
        }
    },
    {
        name: "status2",
        field_name: "status2",
        unit: "",
        index: 12,
        coefficient: 1,
        dataType: "bitBE5-5",
        optionList: {
            0: "invalid",
            1: "valid"
        }
    }
];

let paraDef = {
    app_38: {
        name: "pwron_delay",
        field_name: "pwron_delay",
        unit: "ms",
        index: 38,
        type: "uint16LE"
    },
    app_70: {
        name: "periodUP",
        field_name: "periodUP",
        unit: "s",
        type: "uint32LE"
    },
    app_74: {
        name: "periodRead",
        field_name: "periodRead",
        unit: "s",
        type: "uint32LE"
    },
    app_110: {
        name: "cov_weight",
        field_name: "cov_weight",
        unit: "kg",
        type: "int16BE",
        coefficient: 0.1,
        decimal: 1
    },
    app_150: {
        name: "addr",
        field_name: "addr",
        unit: "",
        type: "uint8"
    }
};

let pdata = {};
let tdata = {};

let payParser = new PayloadParser({
    device: device,
    msg: msg,
    frameInfo: frameInfo,
    appInfo: appInfo,
    paraInfo: paraDef,
});

if (port === 214) {
    pdata = payParser.paras();
    tdata = null;
} else {
    tdata = payParser.telemetry();
    pdata = null;
}

return {
    telemetry_data: tdata,
    server_attrs: null,
    shared_attrs: pdata
};

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8. Third-Party Platform Data Subscription

8.1 MQTT Topic

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

8.2 Sample Uplink Payload

{
    "eui": "6353012af10a9331",
    "active_time": "2026-02-05T08:35:48.000Z",
    "thingModelId": "88304368717139973",
    "thingModelIdName": "sj101cx_21307",
    "telemetry_data": {
        "snr": 13.5,
        "rssi": -51,
        "battery": 3.37,
        "weight": 12.34,
        "precision": 0.01,
        "status1": "stable",
        "status2": "valid"
    }
}

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9. RPC Interface

9.1 RPC Method Name

sj101cx_21307_get

9.2 Parameter Definitions

Parameter Name	App Address	Unit	Description
pwron_delay	38	ms	Power-on delay time; default: 1000 ms
periodUP	70	s	Telemetry reporting interval
periodRead	74	s	Register polling interval
cov_weight	110	kg	Weight change-of-value (COV) threshold
addr	150	—	Modbus slave address

9.3 Refined RPC Code

let paraDef = {
    app_38: {
        name: "pwron_delay",
        field_name: "pwron_delay",
        unit: "ms",
        index: 38,
        type: "uint16LE"
    },
    app_70: {
        name: "periodUP",
        field_name: "periodUP",
        unit: "s",
        type: "uint32LE"
    },
    app_74: {
        name: "periodRead",
        field_name: "periodRead",
        unit: "s",
        type: "uint32LE"
    },
    app_110: {
        name: "cov_weight",
        field_name: "cov_weight",
        unit: "kg",
        type: "int16BE",
        coefficient: 0.1,
        decimal: 1
    },
    app_150: {
        name: "addr",
        field_name: "addr",
        unit: "",
        type: "uint8"
    }
};

let frames = RPCHelper.buildFrame({
    paraDef: paraDef,
    params: params
});

let redoBuffer = RPCHelper.redo();
let dnBuffer = Buffer.alloc(
    frames.writeBuffer.length + frames.readBuffer.length + redoBuffer.length
);

frames.writeBuffer.copy(dnBuffer, 0);
frames.readBuffer.copy(dnBuffer, frames.writeBuffer.length);
redoBuffer.copy(dnBuffer, frames.writeBuffer.length + frames.readBuffer.length);

logger.info("get/set sj101cx para");

let msg = RPCHelper.makeMSG({
    msgType: Utils.msgType.paras,
    device: device,
    dnBuffer: dnBuffer,
    sleepTime: 0,
});

return [msg];

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10. Template Selection

In the ThinkLink platform, search for the device template using either:

SJ101CX

or, by business type:

21307