Device Model: BGT-SMPS

Model catalog

Search for these models in ThinkLink by name or ID.

Model type	Name	id_name	Platform model ID
RPC	[BGT-SMPS GET] para	bgt_smps_get_25101	102256370513874949
RPC	[BGT-SMPS SET] para	bgt_smps_set_25101	102256081450831877
Template	BGT-SMPS-25101		102256727507865605
Thing Model	[BGT-SMPS]	bgt_smps_25101	102254589725642757
Thing Model	[BGT-25101-BGT-SMPS资产] 区域聚合	bgt_smps_asset_25101	119677174411063296
Parameter Thing Model	[BGT-SMPS-PARA]	bgt_smps_para_25101	102255300635004933

Template Name: BGT-SMPS-25101
Business Code: 25101

1. Sensor Introduction

BGT-SMPS is a multi-in-one soil parameter sensor developed by GXHY / Beijing Guoxinhuayuan Technology Co., Ltd. It supports the collection of soil temperature, soil moisture, soil EC, soil salinity, soil nitrogen, soil phosphorus, soil potassium, soil pH, and other parameters.

The sensor uses an RS-485 interface and communicates through the standard Modbus-RTU protocol. The default address is 01, and the default communication parameters are 9600, 8N1. The sensor can be directly inserted into or buried in soil, making it suitable for agriculture, environmental monitoring, greenhouses, soil testing, and other scenarios.

In this integration solution, BGT-SMPS is connected to the platform through KC21 + EdgeBus + LoRaWAN + ThinkLink. KC21 reads the Modbus data from the sensor through RS-485 and then reports the data to the ThinkLink platform via LoRaWAN.

2. Product Features

Feature	Description
Multi-parameter integration	Supports soil temperature, moisture, EC, salinity, nitrogen, phosphorus, potassium, pH, and other parameters
Modbus-RTU communication	Standard RS-485 / Modbus-RTU protocol, easy to connect to data collectors
High measurement accuracy	High measurement accuracy for temperature, moisture, EC, pH, and other parameters
Fast response	Short stabilization time after power-on, enabling fast data collection
Good protection performance	Epoxy resin sealing, waterproof rating IP68
Corrosion-resistant probe	Probe material: 316L stainless steel
Suitable for buried installation	The probe can be fully inserted into soil, or the entire device can be buried in soil

3. Application Scope

BGT-SMPS is suitable for the following scenarios:

Application Scenario	Description
Water-saving agricultural irrigation	Monitors soil temperature, moisture, and fertility parameters for irrigation strategy optimization
Meteorological monitoring	Works with agricultural weather stations for soil environment monitoring
Environmental monitoring	Used for soil environment data collection
Greenhouses	Monitors crop root-zone environmental parameters
Flower and vegetable cultivation	Used for refined planting management
Grassland and pasture	Monitors soil moisture and nutrient status
Rapid soil testing	Quickly obtains multi-parameter soil data on site
Scientific experiments	Used for data collection in agriculture, ecology, soil, and related experiments

4. Collector Information

4.1 Hardware Information

Item	Content
Collector model	KC21
Communication method	LoRaWAN
Sensor interface	RS-485
Collection protocol	Modbus-RTU
Power supply	Battery powered
Peripheral power supply	KC21 provides approximately 15.1 V to the sensor
Business code	25101
Template name	BGT-SMPS-25101
Number of collected devices	Supports 3 soil sensors by default
Sensor address configuration	Addresses are stored in APP parameter areas 150, 151, and 152
Period configuration	Period parameters are 70, 74, and 78 respectively

4.2 Wiring Information

Power and Communication Interface

The BGT-SMPS sensor uses a 4-core cable. The wiring definition is as follows:

Wire Color	Definition	Description
Red	Power+	DC 9–24 V / the newer manual specifies DC 5–24 V
Black	GND	Power negative
Yellow	RS485_A	RS-485 A
Green	RS485_B	RS-485 B

In this solution:

KC21 Side	BGT-SMPS Side
Peripheral power output +	Red wire Power+
GND	Black wire GND
RS485 A	Yellow wire RS485_A
RS485 B	Green wire RS485_B

Sensor Interface

Item	Content
Interface type	RS-485
Communication protocol	Modbus-RTU
Default address	0x01
Baud rate	9600
Data bits	8
Stop bits	1
Parity	None

5. Data Collection

In this solution, the following registers are read through Modbus:

Parameter	Modbus Register Address	PLC Address	Data Type	Description
Soil temperature	0x0000	40001	int16	1 decimal place; negative values use two’s complement
Soil moisture	0x0001	40002	uint16	1 decimal place, 0–100%
Soil EC	0x0002	40003	uint16	No decimal places, unit: μS/cm
Soil salinity	0x0003	40004	uint16	No decimal places, unit: mg/L
Soil nitrogen	0x0004	40005	uint16	No decimal places, unit: mg/kg
Soil phosphorus	0x0005	40006	uint16	No decimal places, unit: mg/kg
Soil potassium	0x0006	40007	uint16	No decimal places, unit: mg/kg
Soil pH	0x0007	40008	uint16	2 decimal places

Example sensor read command:

01 03 00 00 00 08 44 0C

Meaning:

Byte	Content	Description
01	Slave address	Default address 1
03	Function code	Read holding registers
00 00	Start register	Starts from 0x0000
00 08	Number of registers	Reads 8 consecutive registers
44 0C	CRC16	Modbus CRC check

5.1 Register Definition

No.	Parameter Name	Field Name	Unit	Index	Type	Coefficient	Decimal Places
1	Soil temperature	soil_temperature	℃	6	int16be	0.1	1
2	Soil moisture	soil_moisture	%	8	uint16be	0.1	1
3	Soil EC	soil_ec	μS/cm	10	uint16be	1	0
4	Soil salinity	soil_salinity	mg/L	12	uint16be	1	0
5	Soil nitrogen	soil_nitrogen	mg/kg	10	uint16be	0.088	3
6	Soil phosphorus	soil_phosphorus	mg/kg	10	uint16be	0.044	3
7	Soil potassium	soil_potassium	mg/kg	10	uint16be	0.066	3
8	Soil pH	soil_ph	pH	20	uint16be	0.01	2

Note: In this project’s thing model, the soil nitrogen, phosphorus, and potassium fields use the EC data position index: 10 and are calculated through coefficients: 0.55 × 0.16, 0.55 × 0.08, and 0.55 × 0.12, respectively.

5.2 Status Bit Definition

No separate sensor status bit is defined in this solution.

The thing model script handles collection timeout status as follows:

if((tdata?.status&0x02)===0x02) {
    const status=tdata.status
    tdata={ ...(device.telemetry_data?.[thingModelId] ?? {})}
    tdata.status=status
}

Logic description:

Status Bit	Meaning	Processing Method
status & 0x02	Collection timeout / time out	Keep the original telemetry data and only update the status value

6. EdgeBus Model

This device itself is not a LoRaWAN sensor. It is an RS-485 / Modbus-RTU sensor, so the built-in EdgeBus of KC21 is required to execute Modbus collection logic.

In this solution, EdgeBus is configured with 3 sensor channels by default:

Channel	Period Parameter Index	Address Parameter Index
Channel 1	70	150
Channel 2	74	151
Channel 3	78	152

6.1 EB Configuration Parameters

Parameter	Value
SwVersion	31
BaudRate	9600
StopBits	1
DataBits	8
Checkbit	NONE
Battery	true
ConfirmDuty	60
BzType	25101
BzVersion	11
LoRaWAN Port	22
version	0x88
dataType	0x01
Protocol	Modbus
Modbus function code	0x03
Default sensor address	Read from APP parameter area
APP address parameters	150, 151, 152
Query period parameters	70, 74, 78

6.2 EB Code

import {Buffer} from "buffer";
import {buildOtaFile} from "@EBSDK/run";
import {LoraUpEvent} from "@EBSDK/EBCompiler/all_variable";
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, HwTypeEnum} from "@EBSDK/otaConfig";
////////////////////////////////////////////////////////////////////////////////////////
let eventInfo: UserConfUPItem[] = [];
let otaConfig = getOtaConfig({
    SwVersion:31,
    BaudRate: 9600,
    StopBits: 1,
    DataBits: 8,
    Checkbit: CheckbitEnum.NONE,
    Battery: true,
    ConfirmDuty: 60,
    BzType: 25101,
    BzVersion: 11
})
for(let i=0;i<3;i++) {
    let userConf:UserConfUPItem={
        name: "BGT_SMPS_6CH", version: "0x88",dataType: "0x01", port: 22,  upPeriod: "10y",
        quInfo: [
            {
                protocol: "modbus", addr: "0x01", code: "0x03", periodIndex: 70,
                indexAPP: 150, indexCMD: 0, copySize: 1,
                isLast:true,
                listVal: [
                    { start: "0", end: "7" }
                ]
            }
        ]
    }
    userConf.name="BGT_SMPS_6CH_"+i.toString();
    userConf.quInfo[0].periodIndex=70+i*4
    userConf.quInfo[0].indexAPP = 150+i;
    eventInfo.push(userConf)
}
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 Description

Current EB logic description:

1. KC21 connects to the BGT-SMPS soil multi-parameter sensor through RS-485.
2. EdgeBus uses the Modbus-RTU protocol to read sensor data.
3. Three collection events are generated by default, corresponding to 3 sensor channels.
4. The 485 address of each sensor is read from the APP parameter area:
   • Channel 1: app_150
   • Channel 2: app_151
   • Channel 3: app_152
5. The collection period of each sensor is controlled by the following parameters:
   • Channel 1: app_70
   • Channel 2: app_74
   • Channel 3: app_78
6. Each collection uses Modbus function code 0x03 to read 8 consecutive registers.
7. Uplink uses LoRaWAN port 22. The frame header tags are:
   • 0x88
   • 0x01
8. The value at subDevice.index = 5 in the uplink data is used to distinguish different sub-devices / sensors.

7. Thing Model

7.1 Basic Thing Model Information

Item	Content
Thing model name	BGT-SMPS-25101
Template name	BGT-SMPS-25101
Business code	25101
Device type	Multi-in-one soil sensor
Communication method	KC21 + LoRaWAN
Uplink port	22
Data length	22
Parse RSSI	Yes
Parse battery voltage	Yes, battery: 4
Sub-device identification	index: 5, type: uint8
Uplink frame identifier	0x88 0x01

7.2 Uplink Frame Structure

Byte Index	Content	Description
0	0x88	Business version / frame identifier
1	0x01	Data type
4	battery	Battery voltage field
5	subDevice	Sub-device number
6–7	soil_temperature	Soil temperature
8–9	soil_moisture	Soil moisture
10–11	soil_ec	Soil EC
12–13	soil_salinity	Soil salinity
20–21	soil_ph	Soil pH

Note: According to the provided thing model script, soil nitrogen, phosphorus, and potassium are all calculated based on the data at index: 10 using different conversion coefficients.

7.3 Thing Model Script

let port = msg?.userdata?.port || null;
if(port != 22) return null

let frameInfo = {
    port: 22,
    dataLen: 22,
    rssi: true,
    battery: 4,
    subDevice: { index: 5, type: "uint8" },
    tagList: [
        { index: 0, tag: 0x88 },
        { index: 1, tag: 0x01 }
    ]
};

let appInfo = [
    { name: "Soil Temperature", field_name: "soil_temperature", unit: "℃", index: 6, type: "int16be", coefficient: 0.1, decimal: 1 },
    { name: "Soil Moisture", field_name: "soil_moisture", unit: "%", index: 8, type: "uint16be", coefficient: 0.1, decimal: 1 },
    { name: "Soil EC", field_name: "soil_ec", unit: "μS/cm", index: 10, type: "uint16be", coefficient: 1, decimal: 0 },
    { name: "Soil Salinity", field_name: "soil_salinity", unit: "mg/L", index: 12, type: "uint16be", coefficient: 1, decimal: 0 },
    { name: "Soil Nitrogen", field_name: "soil_nitrogen", unit: "mg/kg", index: 10, type: "uint16be", coefficient: 0.088, decimal: 3 },
    { name: "Soil Phosphorus", field_name: "soil_phosphorus", unit: "mg/kg", index: 10, type: "uint16be", coefficient: 0.044, decimal: 3 },
    { name: "Soil Potassium", field_name: "soil_potassium", unit: "mg/kg", index: 10, type: "uint16be", coefficient: 0.066, decimal: 3 },
    { name: "Soil pH", field_name: "soil_ph", unit: "pH", index: 20, type: "uint16be", coefficient: 0.01, decimal: 2 }
];

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

let tdata = payParser.telemetry()

if((tdata?.status & 0x02) === 0x02) {
    const status = tdata.status
    tdata = { ...(device.telemetry_data?.[thingModelId] ?? {}) }
    tdata.status = status
}

return {
    sub_device: tdata == undefined ? null : tdata.addr,
    telemetry_data: tdata,
    server_attrs: null,
    shared_attrs: null
}

8. Third-Party Platform Data Subscription

8.1 MQTT Topic

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

8.2 Example Reported Data

{
    "eui": "6353012af10a9331",
    "active_time": "2026-05-03T07:36:00.000Z",
    "thingModelId": "BGT-SMPS-25101",
    "thingModelIdName": "bgt_smps_25101",
    "telemetry_data": {
        "snr": 13.5,
        "rssi": -51,
        "battery": 3.37,
        "addr": 1,
        "soil_temperature": 23.6,
        "soil_moisture": 35.6,
        "soil_ec": 1234,
        "soil_salinity": 1356,
        "soil_nitrogen": 108.592,
        "soil_phosphorus": 54.296,
        "soil_potassium": 81.444,
        "soil_ph": 6.86,
        "status": 0
    }
}

9. RPC

9.1 RPC Name

Type	Name
Parameter setting RPC	bgt_smps_set_25101
Parameter validation name	bgt_smps_25101_set

Note: During actual platform configuration, it is recommended to keep the RPC name and the parameter thing model validation name consistent to avoid call failures caused by naming inconsistency.

9.2 Parameter Definition

Parameter Name	Field Name	APP Index	Type	Unit	Description
pwron_delay	pwron_delay	38	uint16le	ms	Peripheral power-on delay
period1	period1	70	uint32LE	s	Collection period of sensor channel 1
period2	period2	74	uint32LE	s	Collection period of sensor channel 2
period3	period3	78	uint32LE	s	Collection period of sensor channel 3
addr1	addr1	150	uint8	-	485 address of sensor channel 1
addr2	addr2	151	uint8	-	485 address of sensor channel 2
addr3	addr3	152	uint8	-	485 address of sensor channel 3

9.3 RPC Code

9.3.1 Set Parameters

let classMode = (device && device.shared_attrs && device.shared_attrs.class_mode) || "ClassA";
let intervalms = classMode === "ClassA" ? 0 : 2000;

const rpcName = "bgt_smps_set_25101"

let paraDef = {
    app_38: { name: "pwron_delay", field_name: "pwron_delay", unit: "ms", index: 38, type: "uint16le" },
    app_70: { name: "period1", field_name: "period1", unit: "s", type: "uint32LE" },
    app_74: { name: "period2", field_name: "period2", unit: "s", type: "uint32LE" },
    app_78: { name: "period3", field_name: "period3", unit: "s", type: "uint32LE" },
    app_150: { name: "addr1", field_name: "addr1", unit: "", type: "uint8" },
    app_151: { name: "addr2", field_name: "addr2", unit: "", type: "uint8" },
    app_152: { name: "addr3", field_name: "addr3", 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);
frames.writeBuffer.copy(dnBuffer, 0)
frames.readBuffer.copy(dnBuffer, frames.writeBuffer.length)

logger.info("set para")

let msgQue = Utils.makeParaSetMSG({
    device: device,
    classMode: classMode,
    rpcName: rpcName,
    params: params,
    paraDownBuffer: dnBuffer,
    extraAppBuffer: redoBuffer
})

if (msgQue.length == 0) return null

return msgQue

9.3.2 Read Parameters

let classMode = (device && device.shared_attrs && device.shared_attrs.class_mode) || "ClassA";
let sleepMs = classMode === "ClassA" ? 500 : 5000;

let paraDef = {
    app_38: { name: "pwron_delay", field_name: "pwron_delay", unit: "ms", index: 38, type: "uint16le" },
    app_70: { name: "period1", field_name: "period1", unit: "s", type: "uint32LE" },
    app_74: { name: "period2", field_name: "period2", unit: "s", type: "uint32LE" },
    app_78: { name: "period3", field_name: "period3", unit: "s", type: "uint32LE" },
    app_150: { name: "addr1", field_name: "addr1", unit: "", type: "uint8" },
    app_151: { name: "addr2", field_name: "addr2", unit: "", type: "uint8" },
    app_152: { name: "addr3", field_name: "addr3", unit: "", type: "uint8" },
}

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

let msg = RPCHelper.makeMSG({
    msgType: Utils.msgType.paras,
    device: device,
    dnBuffer: frames.readBuffer,
    sleepTime: sleepMs,
})

return [msg]

10. Template Selection

Search for the following template in the ThinkLink platform:

BGT-SMPS-25101

Or search by business type:

25101

Recommended search keywords:

Search Method	Keyword
By template name	BGT-SMPS-25101
By device model	BGT-SMPS
By business code	25101
By application type	Soil multi-parameter sensor
By collection method	KC21 / RS-485 / Modbus / LoRaWAN