S31-FB/S31B-FB – NB-IoT/LTE-M Temperature & Humidity Sensor

S31-FB/S31B-FB

1. Introduction

1.1 What is Temperature & Humidity Sensor

The Dragino S31-FB/FS and S31B-FB/FS are NB-IoT/LTE-M Temperature and Humidity Sensor for Internet of Things solution. It is used to measure the surrounding environment temperature and relative air humidity precisely, and then upload to IoT server via NB-IoT or CAT-M1 network.

The temperature & humidity sensor used in S31x-FB is SHT31, which is fully calibrated, linearized, and temperature compensated digital output from Sensirion, it provides a strong reliability and long-term stability. The SHT31 is fixed in a waterproof anti-condensation casing for long term use.

S31-FB/FS and S31B-FB/FS supports different uplink methods include MQTT, MQTTs, TCP or UDP for different application requirement. and Support Uplinks to various IoT Servers.

S31-FB/FS and S31B-FB/FS is powered by 8500mAh Li-SOCI2 battery or solar powered + 3000mAh Li-ion battery, It is designed for long term use up to several years. (Real-world battery life depends on the use environment, update period and uplink method. Please check related Power Analyze report).

*make sure you have NB-IoT or CAT-M1 coverage locally.

1.2 Features

NB-IoT Bands: B1/B2/B3/B4/B5/B8/B12/B13/B17/B19/B20/B25/B26/B28/B65/B66/B85/B106
CAT-M1 / LTE-M Bands: B1/B2/B3/B4/B5/B8/B12/B13/B18/B19/B20/B25/B26/B28/B66/B85/B106
Ultra-low power consumption
External 3 meters SHT31 probe (For S31-FB)
Measure range -40°C ~ 80°C
Temperature & Humidity alarm
Multiply Sampling and one uplink
Uplink via MQTT, MQTTs, TCP or UDP
GNSS for Location Report
Support Bluetooth v5.1 remote configure and update firmware
Uplink on periodically
Downlink to change configure
8500mAh Li/SOCl2 Battery (S31x-FB)
Solar panel + 3000mAh Li-ion battery (S31x-FS)
Nano SIM card slot for NB-IoT SIM

1.3 Specification

Common DC Characteristics:

Supply Voltage: 3.0v ~ 3.6v
Operating Temperature: -40 ~ 85°C

Temperature Sensor:

Range: -40 to + 80°C
Accuracy: ±0.2 @ 0-90 °C
Resolution: 0.1°C
Long Term Shift: <0.03 °C/yr

Humidity Sensor:

Range: 0 ~ 99.9% RH
Accuracy: ± 2%RH ( 0 ~ 100%RH)
Resolution: 0.01% RH
Long Term Shift: <0.25 %RH/yr

NB-IoT/LTE-M Spec:

Module: nRF9151-NGFF
Support Bands:
- NB-IoT Bands:
  - B1 @H-FDD: 2100MHz
  - B2 @H-FDD: 1900MHz
  - B3 @H-FDD: 1800MHz
  - B4 @H-FDD: 2100MHz
  - B5 @H-FDD: 860MHz
  - B8 @H-FDD: 900MHz
  - B12 @H-FDD: 720MHz
  - B13 @H-FDD: 740MHz
  - B17 @H-FDD: 730MHz
  - B19 @H-FDD: 870MHz
  - B20 @H-FDD: 790MHz
  - B25 @H-FDD: 1900MHz
  - B26 @H-FDD: 876MHz
  - B28 @H-FDD: 750MHz
  - B65 @H-FDD: 2155MHz
  - B66 @H-FDD: 2000MHz
  - B85 @H-FDD: 700MHz
  - B106 @H-FDD: 900MHz
- CAT-M1 / LTE-M Bands:
  - B1 @H-FDD: 2100MHz
  - B2 @H-FDD: 1900MHz
  - B3 @H-FDD: 1800MHz
  - B4 @H-FDD: 2100MHz
  - B5 @H-FDD: 860MHz
  - B8 @H-FDD: 900MHz
  - B12 @H-FDD: 720MHz
  - B13 @H-FDD: 740MHz
  - B18 @H-FDD: 870MHz
  - B19 @H-FDD: 870MHz
  - B20 @H-FDD: 790MHz
  - B25 @H-FDD: 1900MHz
  - B26 @H-FDD: 876MHz
  - B28 @H-FDD: 750MHz
  - B66 @H-FDD: 2000MHz
  - B85 @H-FDD: 700MHz
  - B106 @H-FDD: 900MHz

Battery:

Li/SOCI2 un-chargeable battery
Capacity: 8500mAh
Self Discharge: <1% / Year @ 25°C
Max continuously current: 130mA
Max boost current: 2A, 1 second

Power Consumption:

STOP Mode: 14uA @ 3.3v
Max transmit power: 350mA @ 3.3v

1.4 Applications

Smart Buildings & Home Automation
Logistics and Supply Chain Management
Smart Metering
Smart Agriculture
Smart Cities
Smart Factory

1.5 Sleep mode and working mode

Deep Sleep Mode: Sensor doesn't have any NB-IoT/CAT-M1 activate. This mode is used for storage and shipping to save battery life.

Working Mode: In this mode, Sensor will work as NB-IoT Sensor to Join NB-IoT network and send out sensor data to server. Between each sampling/tx/rx periodically, sensor will be in IDLE mode), in IDLE mode, sensor has the same power consumption as Deep Sleep mode.

1.6 Button & LEDs

Behavior on ACT	Function	Action
1~3s	Send an uplink	If sensor has already attached to NB-IoT/CAT-M1 network, sensor will send an uplink packet, blue led will blink once. Meanwhile, BLE module will be active and user can connect via BLE to configure device.
>3s	Active Device	Green led will fast blink 5 times. And then start to attach NB-IoT/CAT-M1 network. Once sensor is active, BLE module will be active and user can connect via BLE to configure device, no matter if device attach NB-IoT/CAT-M1 network or not.
x5	Deactivate Device	Red led will solid on for 5 seconds. Means device is in Deep Sleep Mode.
x1	Toggle Serial Communication	Press the ACT button once to activate the serial communication function, and Ready will be displayed in the serial tool. Press the ACT button once again to disable the serial communication function. The green led will turn on when the button is pressed, and then the red led will blink once to indicate that the serial communication has been disabled.

Note: When the device is executing a program, the buttons may become invalid. It is best to press the buttons after the device has completed the program execution.

1.7 BLE connection

S31x-FB support BLE remote configure and firmware update.

BLE can be used to configure the parameter of sensor or see the console output from sensor. BLE will be only activate on below case:

Press button to send an uplink
Press button to active device.
Device Power on or reset.

If there is no activity connection on BLE in 60 seconds, sensor will shut down BLE module to enter low power mode.

1.8 Pin Definitions , Switch & SIM Direction

1.8.1 Jumper JP2

Power on Device when put this jumper.

Power off device when take out this jumper

1.8.2 BOOT MODE / SW1

The BOOT MODE / SW1 switch has no function on -FB products. Always keep the switch in the FLASH position.

1.8.3 Reset Button

Press to reboot the device.

1.8.4 SIM Card Direction

See this link. How to insert SIM Card.

1.9 Hardware Variant

Model	Photo	Probe Info
S31-FB		1 x SHT31 Probe Cable Length : 3 meters
S31B-FB		1 x SHT31 Probe Installed in device.

1.10 Mechanical

Currently, our S31-FB/FS and S31B-FB/FS series includes the following models: S31x-FB, S31x-FS, and S31x-FB2.

The S31x-FB is the standard battery-powered version, the S31x-FS is the standard solar-powered version, and the S31x-FB2 is the version with increased battery capacity.

The main difference between the S31x-FB2 and the standard S31x-FB model lies in the battery used: the S31x-FB uses an 8500 mAh lithium battery, while the S31x-FB2 uses a 19000 mAh battery. In terms of firmware and basic functionality, it is fully compatible with the S31x-FB.

1.10.1 for FB version

1.10.2 for FS version

1.10.3 for FB2 version

2. Use S31x-FB/FS to communicate with IoT Server

2.1 Send data to IoT server via NB-IoT/CAT-M1 network

The S31x-FB/FS is equipped with a NB-IoT module, the pre-loaded firmware in S31x-FB/FS will get environment data from sensors and send the value to local NB-IoT network via the NB-IoT module. The NB-IoT network will forward this value to IoT server via the protocol defined by S31x-FB/FS.

Below shows the network structure:

There are two version: -GE and -1T version of S31x-FB/FS.

GE Version: This version doesn't include SIM card or point to any IoT server. User needs to use AT Commands to configure below two steps to set S31x-FB/FS send data to IoT server.

Install NB-IoT SIM card and configure APN. See instruction of Attach Network.
Set up sensor to point to IoT Server. See instruction of Configure to Connect Different Servers.

Below shows result of different server as a glance.

Servers	Dash Board	Comments
Node-Red
DataCake
Tago.IO
General UDP	Raw Payload. Need Developer to design Dash Board
General MQTT	Raw Payload. Need Developer to design Dash Board
ThingSpeak
ThingsBoard

1T Version: This version has 1NCE SIM card pre-installed and configure to send value to ThingsEye. User Just need to select the sensor type in ThingsEyeand Activate S31x-FB and user will be able to see data in ThingsEye. See here for ThingsEye Config Instruction.

2.2 Payload Types

S31x-FB supports JSON payloads only. Use AT+PRO to select the connection protocol with the corresponding parameters:

AT+PRO=2,0 // UDP connection with JSON payload
AT+PRO=3,0 // MQTT connection with JSON payload
AT+PRO=4,0 // TCP connection with JSON payload

Note

The default is AT+QGPS=0 // The GPS function is not enabled. Therefore, the GPS collection time in the following example paylaod does not follow the system time, and the latitude and longitude are 0.

2.2.1 Status Packet

Each time the device is activated, joins the network, and connects to the server, it sends a status packet containing device and firmware information.

Example payload:

{
  "IMEI": "355025936334455",
  "Image Version": "v1.1.2",
  "NB-IoT Stack": "NRF9151-001",
  "Model": "S31x-FB"
}

Field	Description
`IMEI`	International Mobile Equipment Identity of the device.
`Image Version`	Device firmware version.
`NB-IoT Stack`	NB-IoT stack identifier reported by the device.
`Model`	Device model.

2.2.2 General Json Format(Type=0)

This is the General Json Format. As below:

{
  "IMEI": "355025936334455",
  "IMSI": "460240275256466",
  "Model": "S31x-FB",
  "fcnt": "1",
  "signal": "24",
  "bat": 3.57,
  "temperature": 24.2,
  "humidity": 45.2,
  "alarm": "0",
  "i_flag": "0",
  "MCC": "460",
  "MNC": "0",
  "Cell_id": "46134845",
  "Cell_area": "7479",
  "time": "2026-10-30T09:41:23Z",
  "latitude": 0.000000,
  "longitude": 0.000000,
  "gps_time": "00/00/00,00:00:00",
  "1": ["28.5,61.1,2026-10-20T23:59:26Z"],
  "2": ["28.5,61.2,2026-10-21T00:00:26Z"],
  "3": ["28.5,61.1,2026-10-21T00:01:26Z"],
  "4": ["24.4,45.0,2026-10-30T09:38:23Z"],
  "5": ["24.3,45.0,2026-10-30T09:39:23Z"],
  "6": ["24.2,45.1,2026-10-30T09:40:23Z"],
  "7": ["24.2,45.1,2026-10-30T09:41:23Z"],
  "8": ["24.2,45.2,2026-10-30T09:41:23Z"]
}

Current readings and historical samples:

The top-level temperature and humidity fields are the readings reported for the current uplink. Numbered entries contain historical samples with their own timestamps.
With AT+CLOCKLOG=1,65535,1,8, the numbered keys "1" through "8" hold up to eight samples. Each entry is a JSON array containing one comma-separated string: temperature (°C),relative humidity (%RH),sampling time (UTC).

Example:

Device and sensor fields:

Field	Description
`IMEI`	Device identifier, reported as a string.
`IMSI`	Mobile subscriber identifier associated with the SIM, reported as a string.
`Model`	Device model. Example: `"S31x-FB"`.
`fcnt`	Uplink frame counter, reported as a string. Example: `"1"`.
`bat`	Battery voltage in volts. Example: `3.57` means 3.57 V.
`temperature`	Temperature in °C. Example: `24.2` means 24.2 °C.
`humidity`	Relative humidity in %RH. Example: `45.2` means 45.2 %RH.
`i_flag`	Interrupt flag: `"0"` = normal uplink; `"1"` = interrupt-triggered uplink.
`alarm`	Alarm flag: `"0"` = normal uplink; `"1"` = temperature or humidity alarm uplink.

Serving cell information:

MCC (Mobile Country Code): Identifies the country or region of the mobile network.
MNC (Mobile Network Code): Identifies the operator's network within that country or region. Together, MCC and MNC identify the mobile network.
Cell_id (Cell Identifier): Identifies the serving cell within the mobile network.
Cell_area (Cell Area Code): Identifies the network area that contains the serving cell.

Signal strength (signal): The cellular signal quality indicator is reported as a string.

Value	Signal strength
`"0"`	−113 dBm or less
`"1"`	−111 dBm
`"2"`–`"30"`	−109 dBm to −53 dBm
`"31"`	−51 dBm or greater
`"99"`	Unknown or not detectable

Time and GPS fields:

time: Device timestamp in UTC. In "2026-10-30T09:41:23Z", the Z suffix denotes UTC.
gps_time: Timestamp of the GPS position fix, separate from time. In this example, GPS is disabled and the field contains the placeholder "00/00/00,00:00:00".
latitude and longitude: GPS coordinates in decimal degrees. For example, 22.706150 and 114.242830 mean 22.706150° N and 114.242830° E.

3. Configure S31x-FB

3.1 Configure Methods

S31x-FB supports below configure method:

AT Command via Bluetooth Connection (Recommended): BLE Configure Instruction.

AT Command via UART Connection : See UART Connection.

3.2 Serial Access Password

After the Bluetooth or UART connection is successful, use the Serial Access Password to enter the AT command window.

The label on the box of the node will print the initial password: AT+PIN=xxxxxx, and directly use the six-digit password to access the AT instruction window.

If you need to change the password, use AT+PWORD= xxxxxx (6 characters).

Note: After entering the command, you need to add a line break, and you can also set automatic line breaks in the Bluetooth tool or UART connection tool.

3.3 AT Commands Set

AT+? : Help on

AT+ : Run

AT+= : Set the value

AT+=? : Get the value

General Commands

AT+MODEL : Get module information

AT+CFGMOD : Working mode selection

AT+DEUI : Get or set the Device ID

AT+CFG : Print all settings

AT+SERVADDR: Get or Set the Server address

AT+TDC : Get or set the application data transmission interval in s

AT+INTMOD : Get or Set the trigger interrupt mode (0:input,1:falling or rising,2:falling,3:rising)

AT+APN : Get or set the APN

AT+5VT : Get or Set extend the time of 5V power

AT+PRO : Get or Set usage agreement (2:UDP,3:MQTT,4:TCP)

AT+RXDL : Get or Set the receiving time

AT+EXT : Get or Set Count value

AT+SHTEMP:Get or Set alarm of shtemp

AT+SHHUM:Get or Set alarm of shthum

AT+GETSENSORVALUE : Returns the current sensor measurement

AT+DNSCFG : Get or Set DNS Server

AT+SLEEP : Get or Set the sleep mode

AT+IOTMOD: Configure Network Category to be Searched for under LTE RAT

MQTT Management

AT+CLIENT : Get or Set the MQTT clientID

AT+UNAME : Get or Set the MQTT Username

AT+PWD : Get or Set the MQTT password

AT+PUBTOPIC: Get or set MQTT publishing topic

AT+SUBTOPIC: Get or set MQTT subscription topic

AT+MQOS : Set the QoS level of MQTT

AT+TLSMOD : Get or Set the TLS mode

GPS

AT+GTIME : Extend the time to turn on GNSS

AT+QGPS : Turn off and on GPS

AT+QGTDC : Get or set GPS positioning interval in units of h

Information

AT+FDR : Reset Parameters to Factory Default

AT+PWORD : Get or set the System password

AT+LDATA : Get the last upload data

AT+CDP : Read or Clear cached data

AT+PDTA: Print the sector data from start page to stop page

AT+PLDTA: Print the last few sets of data

AT+CLRDTA: Clear the storage, record position back to 1st

AT+GETLOG : Print serial port logs

ATZ : Trig a reset of the MCU

AT+UDPMOD: Get or set UDP working mode

AT+REDPT: Get or Set the function of reconnecting the network to send data

AT+QCOPS: Get or set operator code

AT+DEBUG: Get or Set the debug mode

3.4 Test Uplink and Change Update Interval

By default, Sensor will send uplinks every 20 min.

User can use below commands to change the uplink interval.

AT Command: AT+TDC

Example: AT+TDC=7200 // Set Update Interval to 7200 seconds

Downlink Commands: 0x01

Format: Command Code (0x01) followed by 3 bytes.

Example: 12 hours= 43200 seconds 43200(D)=0xA8C0(H)

Downlink Payload: 01 00 A8 C0 // AT+TDC=43200, Set Update Interval to 12 hours.

Note: User can also push the button for more than 1 second to activate an uplink.

3.5 Set the receiving time

Feature: Extend the receiving time

AT Command: AT+RXDL

Example: AT+RXDL=1000 // Set the receiving time delay to 1000ms

Downlink Commands: 0x03

Format: Command Code (0x03) followed by 3 bytes.

Example: Downlink Payload: 03 00 03 E8 // AT+RXDL=1000

3.6 Reset

Feature: Trig a reset of the MCU.

AT Command: ATZDownlink Commands: 0x04FF

3.7 +5V

Feature: Set extend the time of 5V power.

AT Command: AT+5VT

Example: AT+5VT=2000 // Set extend the time of 5V power to 2000 ms

Downlink Commands: 0x05

Format: Command Code (0x05) followed by 3 bytes.

Example: Downlink Payload: 05 00 07 D0 // AT+5VT=2000

3.8 Trigger an uplink by external interrupt

S31x-FB has an external trigger interrupt function. Users can use the PB15 pin to trigger the upload of data packets.

AT command:

AT+INTMOD // Set the trigger interrupt mode
AT+INTMOD=0 // Disable Interrupt
AT+INTMOD=1 // Trigger by rising and falling edge
AT+INTMOD=2 // Trigger by falling edge
AT+INTMOD=3 // Trigger by rising edge

Downlink Commands: 0x06

Format: Command Code (0x06) followed by 3 bytes.

Example1: Downlink Payload: 06 00 00 01 // AT+INTMOD=1

Example2: Downlink Payload: 06 00 00 03 // AT+INTMOD=3

3.9 Set the QoS level

This command is used to set the QoS level of MQTT.

AT command:

AT+MQOS=xx // 0~2

Downlink command: 0x07

Format: Command Code (0x07) followed by 1 byte.

Ex1: Downlink payload: 0x0700 // AT+MQOS=0

Ex2: Downlink payload: 0x0701 // AT+MQOS=1

3.10 Set the TLS mode

Refer to this link (General MQTT over TLS Connection) to use the TLS mode.

AT Command: AT+TLSMOD

Example 1:

AT+TLSMOD=0,0 // Disable TLS Mode.

Example 2:

AT+TLSMOD=1,0 // No authentication
AT+TLSMOD=1,1 // Perform server authentication
AT+TLSMOD=1,2 // Perform server and client authentication if requested by the remote server

Downlink command: 0x09

Format: Command Code (0x09) followed by 2 bytes.

Example1: Downlink Payload: 09 00 00 // AT+TLSMOD=0,0

Example2: Downlink Payload: 09 01 02 // AT+TLSMOD=1,2

3.11 Set the IPv4 or IPv6

This command is used to set IP version.

AT command:

AT+IPTYPE=1 // IPv4
AT+IPTYPE=2 // IPv6

3.12 Configure Network Category to be Searched for under LTE RAT.

AT command: AT+IOTMOD=a,b,c

a: 0: Disenable eMTC; 1: Enable eMTC

b: 0: Disenable NB-IoT ; 1. Enable NB-IOT

c: Priority: If two network categories are enabled simultaneously, the device will give priority to the configured category.

Ext1: AT+IOTMOD=1,1,2 ----> Indicates that both eMTC and NB-IoT are enabled, with priority given to the NB-IoT network type.

3.13 Factory data reset

Restore factory Settings configurations.

AT command:

AT+FDR // Reset Parameters to Factory Default.

3.14 Print last few data entries

Feature: Print the last few data entries

AT command: AT+PLDTA

Command Example	4 bytes
AT+PLDTA=5 Print last 5 entries	0001 2026/4/28 04:18:17 3371 temp=25.8 hum=62.5 alarm:false 0002 2026/4/28 04:38:18 3363 temp=24.9 hum=62.4 alarm:false 0003 2026/4/28 04:58:18 3363 temp=24.4 hum=61.7 alarm:false 0004 2026/4/28 05:18:18 3359 temp=24.1 hum=60.9 alarm:false 0005 2026/4/28 05:38:18 3363 temp=24.9 hum=60.7 alarm:false OK

Downlink Command:

No downlink commands for feature

3.15 Print data entries base on page

Feature: Print the sector data from start page to stop page.

AT command: AT+PDTA

Command Example	4 bytes
AT+PDTA=1,1 Print page 1 to 1	E8000 2026/4/28 03:37:20 3406 temp=28.8 hum=69.5 alarm:false E8010 2026/4/28 03:38:17 3402 temp=29.1 hum=68.0 alarm:false E8020 2026/4/28 03:58:17 3375 temp=28.5 hum=68.4 alarm:false E8030 2026/4/28 04:18:17 3371 temp=25.8 hum=62.5 alarm:false E8040 2026/4/28 04:38:18 3363 temp=24.9 hum=62.4 alarm:false E8050 2026/4/28 04:58:18 3363 temp=24.4 hum=61.7 alarm:false E8060 2026/4/28 05:18:18 3359 temp=24.1 hum=60.9 alarm:false E8070 2026/4/28 05:38:18 3363 temp=24.9 hum=60.7 alarm:false OK

AT+PDTA=1,1
Print page 1 to 1

E8000 2026/4/28 03:37:20 3406 temp=28.8 hum=69.5 alarm:false

E8010 2026/4/28 03:38:17 3402 temp=29.1 hum=68.0 alarm:false

E8020 2026/4/28 03:58:17 3375 temp=28.5 hum=68.4 alarm:false

E8030 2026/4/28 04:18:17 3371 temp=25.8 hum=62.5 alarm:false

E8040 2026/4/28 04:38:18 3363 temp=24.9 hum=62.4 alarm:false

E8050 2026/4/28 04:58:18 3363 temp=24.4 hum=61.7 alarm:false

E8060 2026/4/28 05:18:18 3359 temp=24.1 hum=60.9 alarm:false

E8070 2026/4/28 05:38:18 3363 temp=24.9 hum=60.7 alarm:false

Downlink Command:

No downlink commands for feature

3.16 Clear Flash Record

Feature: Clear flash storage for data log feature.

AT command: AT+CLRDTA

Command Example	Function	Response
AT+CLRDTA	Clear date record	Stop Tx events,Please wait for the erase to complete Clear all stored sensor data... Start Tx events OK

Downlink Command: 0x32

Example: 0x32 00 // Same as AT+CLRDTA

3.17 Working mode selection

Feature: Set interrupt mode or count mode (PB15 pin).

AT command: AT+CFGMOD

Command Example	Function
AT+CFGMOD=1	Interrupt mode (default mode)
AT+CFGMOD=2	count mode

Downlink Command: 0x02

Downlink command: 02 01 // Equal to AT+CFGMOD=1
Downlink command: 02 02 // Equal to AT+CFGMOD=2

3.18 Debug mode

Feature: Since the serial communication feature of the NRF9151 module requires activation, this command is intended for users who need to use the serial port for extended periods of time.

AT command: AT+DEBUG

Command Example	Function
AT+DEBUG=1	Enter debugging mode
AT+DEBUG=0	Exit debugging mode,Serial port function disabled

Note:1. This feature remains active for only 5 minutes; it will automatically turn off after 5 minutes.2. Keeping the serial port open continuously increases power consumption in sleep mode; the continuous current is 900 μA.

3.19 Set GTIME open time

Extend the time to turn on GNSS. The automatic GPS location time is extended when the node is activated.

AT Command: AT+GTIME

Example: AT+GTIME=30 // Set the GPS positioning time to 30 seconds

Downlink command: 0x10

Format: Command Code (0x10) followed by 2 bytes.

Example: Downlink Payload: 10 00 1E // AT+GTIME=30

3.20 Turn on/off GPS

AT Command: AT+QGPS

Ex1: AT+QGPS=0 // Turn off GPS
Ex2: AT+QGPS=1 // Turn on GPS

Downlink command: 0x11

Format: Command Code (0x11) followed by 1 byte.

Example: Downlink Payload: 11 01 // AT+QGPS=1

3.21 Set QGPS positioning interval

Feature: Set GPS positioning interval (unit: hour).

When GPS is enabled, the node automatically locates and uplinks each time it passes GTDC time after activation.

AT Command: AT+QGTDC

Example: AT+QGTDC=24 // Set the GPS positioning interval to 24h.

Downlink command: 0x12

Format: Command Code (0x12) followed by 3 bytes.

Example: 24 hours: 24(D)=0x18(H)

Downlink Payload: 12 00 00 18 // AT+QGTDC=24

3.22 Humidity and Temperature alarm function

Feature: Set the alarm thresholds for temperature (SHTEMP) and humidity (SHHUM).

When enabled, the node will trigger an alarm if the temperature/humidity exceeds the configured limits. The valid temperature range is -40 to 125°C.

AT Command:

AT+SHTEMP=min,max //Set the alarm thresholds for temperature.

AT+SHHUM=min,max //Set the alarm thresholds for humidity.

Example:

AT+SHTEMP=0,30 // Alarm when temperature > 30°C
AT+SHTEMP=20,0 // Alarm when temperature < 20°C
AT+SHTEMP=20,30 // Alarm when temperature < 20°C or > 30°C
AT+SHHUM=50,80 // Alarm when humidity < 50% or > 80%

Downlink command: 0x08

Format: Command Code (0x08) followed by 4 bytes. The first two bytes represent the min and max values of SHTEMP, and the last two bytes represent the min and max values of SHHUM.

Example:

Downlink Payload: 08 14 1E 32 50 // AT+SHTEMP=20,30 & AT+SHHUM=50,80
Downlink Payload: 08 00 00 00 00 // Disable temperature and humidity alarms.

For negative payload temperature: calculate it as 65536 + temperature, and take the last two digits (Hex). Example: -40℃: 65536 + (-40) = 65496 (D) = FFD8 (H). Thus, the payload uses D8 to represent -40℃.

Note

To disable the temperature alarm, set both min and max to 0: AT+SHTEMP=0,0.
To disable the humidity alarm, set both min and max to 0: AT+SHHUM=0,0.
To enable only one side of the alarm, set the unused parameter to 0 (e.g., AT+SHTEMP=0,20 only triggers the upper limit alarm).

3.23 Clock logging

Sometimes when we deploy lots of end nodes in field. We want all sensors sample data at the same time, and upload these data together for analyze. In such case, we can use clock loging feature.

We can use this command to set the start time of data recording and the time interval to meet the requirements of the specific collection time of data.

AT command: AT+CLOCKLOG=a,b,c,d

a: 0: Disable Clock logging. 1: Enable Clock Logging

b: Specify First sampling start second: range (0 ~ 3599, 65535) // Note: If parameter b is set to 65535, the log period starts after the node accesses the network and sends packets.

c: Specify the sampling interval: range (0 ~ 255 minutes)

d: How many entries should be uplink on every TDC (max 32)

Note: To disable clock recording, set the following parameters: AT+CLOCKLOG=1,65535,0,0

Example:

AT+CLOCKLOG=1,65535,1,8

After the node sends the first packet, data is recorded to the memory at intervals of 1 minute. For each TDC uplink, the uplink load will include: battery information + the last 8 memory records (payload + timestamp).

Note

Users need to synchronize the server time before configuring this command. If the server time is not synchronized before this command is configured, the command takes effect only after the node is reset.

Downlink command: 0x08

Format: Command Code (0x08) followed by 5 bytes.

Example 1: Downlink Payload: 08 01 FFFF 0F 08 // Set SHT record time: AT+CLOCKLOG=1,65535,15,8
Example 2: Downlink Payload: 08 01 04B0 0F 08 // Set SHT record time: AT+CLOCKLOG=1,1200,15,8

Note

When entering the downlink payload, there must be no Spaces between bytes.

4. Battery & Power Consumption

S31x-FB use ER26500 + SPC1520 battery pack and S31x-FS use 3000mAh Recharable Battery with Solar Panel. See below link for detail information about the battery info and how to replace.

Battery Info & Power Consumption Analyze .

5. Firmware update

5.1 Over-the-Air (OTA) Firmware Update via HTTP

For detailed OTA update instructions, see OTA Upgrade for NB-IoT / LTE-M End Nodes.

Note: Users can upload the firmware binary to any public HTTP server (not a local/private network address) that the device can access, then use the following method to upgrade

Perform the following steps:

① Place the firmware binary (e.g., S31-FB.bin) on an HTTP-accessible server.

② Use a serial port or send the following command to the device: AT+UPGRADE=<firmware_url>

Example: AT+UPGRADE=http://repo.dragino.com/release/NB/S31-FB.bin

After the node receives the upgrade command via downlink, it will perform the upgrade automatically as shown below:

5.2 Firmware Update through UART TTL interface

Firmware and changelog can be downloaded from : Firmware download link
For detailed instructions on how to perform an update via USB TTL, please refer to this link: UART Upgrade for -FB/-FS/-FE models

6. FAQ

6.1 How can I access the nRF9151-NGFF AT Commands?

User can access to nRF9151-NGFF directly and send AT Commands.

See nRF9151-NGFF AT Command set

6.2 -FB & -FS Models (NB-IoT, LTE-M)

Users can follow the instructions in this link to see how to configure to connect to different servers.

6.3 Why is there no LED response when I press the button on the solar panel model?

If the LED does not light up when you press the button, it may be because the battery has entered protection mode.

Solution: To reactivate the battery, simply expose the solar panel to direct sunlight. For more details, please refer to: Battery Protection State (Apply to Solar Panel + Li-ion battery)

6.4 Does this device support GPS positioning?

Yes. This device supports GPS function and can report latitude and longitude coordinates in the uplink payload.

For configuration and usage details, please refer to: Add Location Data on Uplink Packet

7. Order Info

Part Number: S31-FB-XX / S31B-FS-XX

XX:

GE: General version ( Exclude SIM card)
1T: with 1NCE* 10 years 500MB SIM card and Pre-configure to ThingsEye server

8. Packing Info

Package Includes:

S31-FB or S31-FS Temperature & Humidity Sensor x 1
External antenna x 1

Dimension and weight:

Package Size / pcs : 14.0 x 8 x 5 cm
Weight / pcs : 180g

9. Support

Support is provided Monday to Friday, from 09:00 to 18:00 GMT+8. Due to different timezones we cannot offer live support. However, your questions will be answered as soon as possible in the before-mentioned schedule.
Provide as much information as possible regarding your enquiry (product models, accurately describe your problem and steps to replicate it etc) and send a mail to Support@dragino.cc.

1. Introduction​

1.1 What is Temperature & Humidity Sensor​

1.2 Features​

1.3 Specification​

1.4 Applications​

1.5 Sleep mode and working mode​

1.6 Button & LEDs​

1.7 BLE connection​

1.8 Pin Definitions , Switch & SIM Direction​

1.8.1 Jumper JP2​

1.8.2 BOOT MODE / SW1​

1.8.3 Reset Button​

1.8.4 SIM Card Direction​

1.9 Hardware Variant​

1.10 Mechanical​

1.10.1 for FB version​

1.10.2 for FS version​

1.10.3 for FB2 version​

2. Use S31x-FB/FS to communicate with IoT Server​

2.1 Send data to IoT server via NB-IoT/CAT-M1 network​

2.2 Payload Types​

2.2.1 Status Packet​

2.2.2 General Json Format(Type=0)​

3. Configure S31x-FB​

3.1 Configure Methods​

3.2 Serial Access Password​

3.3 AT Commands Set​

3.4 Test Uplink and Change Update Interval​

3.5 Set the receiving time​

3.6 Reset​

3.7 +5V​

3.8 Trigger an uplink by external interrupt​

3.9 Set the QoS level​

3.10 Set the TLS mode​

3.11 Set the IPv4 or IPv6​

3.12 Configure Network Category to be Searched for under LTE RAT.​

3.13 Factory data reset​

3.14 Print last few data entries​

3.15 Print data entries base on page​

3.16 Clear Flash Record​

3.17 Working mode selection​

3.18 Debug mode​

3.19 Set GTIME open time​

3.20 Turn on/off GPS​

3.21 Set QGPS positioning interval​

3.22 Humidity and Temperature alarm function​

3.23 Clock logging​

4. Battery & Power Consumption​

5. Firmware update​

5.1 Over-the-Air (OTA) Firmware Update via HTTP​

5.2 Firmware Update through UART TTL interface​

6. FAQ​

6.1 How can I access the nRF9151-NGFF AT Commands?​

6.2 -FB & -FS Models (NB-IoT, LTE-M)​

6.3 Why is there no LED response when I press the button on the solar panel model?​

6.4 Does this device support GPS positioning?​

7. Order Info​

8. Packing Info​

9. Support​

1. Introduction

1.1 What is Temperature & Humidity Sensor

1.2 Features

1.3 Specification

1.4 Applications

1.5 Sleep mode and working mode

1.6 Button & LEDs

1.7 BLE connection

1.8 Pin Definitions , Switch & SIM Direction

1.8.1 Jumper JP2

1.8.2 BOOT MODE / SW1

1.8.3 Reset Button

1.8.4 SIM Card Direction

1.9 Hardware Variant

1.10 Mechanical

1.10.1 for FB version

1.10.2 for FS version

1.10.3 for FB2 version

2. Use S31x-FB/FS to communicate with IoT Server

2.1 Send data to IoT server via NB-IoT/CAT-M1 network

2.2 Payload Types

2.2.1 Status Packet

2.2.2 General Json Format(Type=0)

3. Configure S31x-FB

3.1 Configure Methods

3.2 Serial Access Password

3.3 AT Commands Set

3.4 Test Uplink and Change Update Interval

3.5 Set the receiving time

3.6 Reset

3.7 +5V

3.8 Trigger an uplink by external interrupt

3.9 Set the QoS level

3.10 Set the TLS mode

3.11 Set the IPv4 or IPv6

3.12 Configure Network Category to be Searched for under LTE RAT.

3.13 Factory data reset

3.14 Print last few data entries

3.15 Print data entries base on page

3.16 Clear Flash Record

3.17 Working mode selection

3.18 Debug mode

3.19 Set GTIME open time

3.20 Turn on/off GPS

3.21 Set QGPS positioning interval

3.22 Humidity and Temperature alarm function

3.23 Clock logging

4. Battery & Power Consumption

5. Firmware update

5.1 Over-the-Air (OTA) Firmware Update via HTTP

5.2 Firmware Update through UART TTL interface

6. FAQ

6.1 How can I access the nRF9151-NGFF AT Commands?

6.2 -FB & -FS Models (NB-IoT, LTE-M)

6.3 Why is there no LED response when I press the button on the solar panel model?

6.4 Does this device support GPS positioning?

7. Order Info

8. Packing Info

9. Support