LTC1/LTC2-FB/FS

1. Introduction

1.1 What is LTC1/LTC2-FB NB-IoT Temperature Transmitter

The Dragino LTC1/LTC2-FB Industrial NB-IoT Temperature Transmitter is designed to monitor temperature for different environment. It supports to read PT100 probe and convert the value to temperature and then upload to IoT server via NB-IoT network*.

LTC2-FB/FS has two internal 24-bit ADC interfaces.

LTC1-FB/FS has one internal 24-bit ADC interfaces.

LTC1/LTC2-FB/FS supports BLE configure and wireless OTA update which make user easy to use.

LTC1/LTC2-FB/FS supports different uplink methods include TCP, MQTT, UDP or MQTTs for different application requirement. and Support Uplinks to various IoT Servers.

LTC1/LTC2-FB/FS is powered by 8500mAh Li-SOCI2 battery or solar powered + 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 coverage locally.

1.2 Features

• NB-IoT Bands: B1/B2/B3/B4/B5/B8/B12/B13/B17/B18/B19/B20/B25/B28/B66/B70/B85 @H-FDD
• Ultra-low power consumption
• For LTC1-FB/FS: max: 1 x monitor temperature channels
• For LTC1-FB/FS: Press the button to immediately take a sample and upload a data packet.
• For LTC2-FB/FS: max: 2 x monitor temperature channels
• Support 3 -wire PT-100
• Temperature alarm
• Multiply Sampling and one uplink
• Uplink via MQTT, MQTTs, TCP, UDP
• Support Bluetooth v5.1 remote configure and update firmware
• Uplink on periodically
• Downlink to change configure
• 8500mAh Battery for long term use (LTC1/LTC2-FB)
• Solar panel + 3000mAh Li-ion battery (LTC1/LTC2-FS)

1.3 Specification

Common DC Characteristics:

• Supply Voltage: Built-in Battery , 2.5v ~ 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

NB-IoT Spec:

NB-IoT Module: NRF9151-NGFF

Support 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
• B18 @H-FDD: 870MHz
• B19 @H-FDD: 870MHz
• B20 @H-FDD: 790MHz
• B25 @H-FDD: 1900MHz
• B28 @H-FDD: 750MHz
• B66 @H-FDD: 2000MHz
• B70 @H-FDD: 2000MHz
• B85 @H-FDD: 700MHz

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: 10uA @ 3.3v
• Max transmit power: 350mA @ 3.3v

1.4 Applications

• Logistics and Supply Chain Management
• Food management
• Cold chains solution
• Industrial Monitoring and Control

1.5 Sleep mode and working mode

Deep Sleep Mode: Sensor doesn't have any NB-IoT 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

LTC1/LTC2-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

1) ISP: upgrade mode, device won't have any signal in this mode. but ready for upgrade firmware. LED won't work. Firmware won't run.

2) Flash: work mode, device starts to work and send out console output for further debug

NOTE

Due to hardware limitations of the NRF9151-NGFF module, this switch cannot actually control the NRF9151-NGFF module.

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 Mechanical

1.9.1 for FB version

1.9.2 for FS version

1.10 Probe Variant

LTC1/LTC2-FB provide default probe version. See below for the variant:

Model	Photo	Description
DR-SI		Standard IP68 Probe Version: LTC1/LTC2-FB with 1 x Standard IP68 PT100 probe. Installation: Insert Cable Length : 2m PT100 Class : Class A Probe Dimension: φ5*30mm Measure Range: -60 ~ 200 °C Suitable Environment: General environment
DR-LT		Low Temperature Version: LTC1/LTC2-FB with 1 x Low Temperature PT100 probe. Installation: Insert Cable Length : 2m PT100 Class : Class A Probe Dimension: φ5*30mm Measure Range: -196 ~ 150 °C Suitable Environment: Low temperature measurement, such as COVID vaccine transport
DR-HT		High Temperature Version: LTC1/LTC2-FB with 1 x high Temperature PT100 probe. Installation: Insert Cable Length : 3m PT100 Class : Class A Probe Dimension: φ4.5*30mm Measure Range: -70 ~ 450 °C Suitable Environment: High Temperature
DR-UHT		Ultra High Temperature Version: LTC1/LTC2-FB with 1 x Ultra high Temperature PT100 probe. Installation: Insert Cable Length : 3m PT100 Class : Class A Probe Dimension: φ6*50mm Measure Range: -40 ~ 600 °C Suitable Environment: Ultra High Temperature
DR-FSA		Food Safety Version: LTC1/LTC2-FB with 1 x Food Safety PT100 probe. Installation: Insert Cable Length : 2m PT100 Class : Class A Probe Dimension: φ4*150mm Measure Range: -40 ~ 260 °C Suitable Environment: Food temperature measurement
DR-FT		Flat Type Version: LTC1/LTC2-FB with 1 x Flat Type PT100 probe. Installation: Attached Cable Length : 2m PT100 Class : Class A Probe Dimension: 3.67.520mm Measure Range: -60 ~ 200 °C Suitable Environment: Attached to the measure point.

2. Use LTC1/LTC2-FB to communicate with IoT Server

2.1 Send data to IoT server via NB-IoT network

The LTC1/LTC2-FB is equipped with a NB-IoT module, the pre-loaded firmware in LTC1/LTC2-FB 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 LTC1/LTC2-FB.

Below shows the network structure:

There are two version: -GE and -1T version of LTC1/LTC2-FB.

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 LTC1/LTC2-FB 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 LTC1//LTC2-FB/FS and user will be able to see data in ThingsEye. See here for ThingsEye Config Instruction.

2.2 Payload Types

To meet different server requirement, LTC1/LTC2-FB supports different payload type.

Includes:

• General JSON format payload(Type=5)

User can specify the payload type when choose the connection protocol. Example:

AT+PRO=2,0 // Use UDP Connection & Json Payload

AT+PRO=3,0 // Use MQTT Connection & Json Payload

AT+PRO=4,0 // Use TCP Connection & Json Payload

2.2.1 General Json Format(Type=0)

Notice

When using the LTC1-CB module, the temperature2 is invalid and is always 0.0 degrees.

This is the General Json Format. As below:

{"IMEI":"355025934932888","IMSI":"460087023300088","Model":"LTC2-FB","fcnt":"0","signal":"29","bat":3.48,"temp1":25.9,"temp2":25.6,"L1":"0","H1":"0","L2":"0","H2":"0","i_flag":"0","time":"2026-9-22T06:33:48Z","latitude":0.000000,"longitude":0.000000,"gps_time":"00/00/00,00:00:00","1":["24.2,24.3,2026-9-16T09:04:39Z"],"2":["24.2,24.3,2026-9-16T09:19:39Z"],"3":["24.2,24.3,2026-9-16T09:34:39Z"],"4":["24.2,24.3,2026-9-16T09:49:39Z"],"5":["24.2,24.3,2026-9-16T10:04:39Z"],"6":["24.2,24.3,2026-9-16T10:19:39Z"],"7":["3046.3,-0.1,2106-2-5T14:32:37Z"],"8":["25.9,25.6,2026-9-22T06:33:48Z"]}

Example:

Notice, from above payload:

• temp1, temp2, Battery, L1, H1, L2, H2, Fcnt, i_flag, Signal & time are the value at uplink time.

• Json entry 1 ~ 8 are the last 1 ~ 8 sampling data as specify by AT+CLOCKLOG=1,65535,15,8 Command. Each entry includes (from left to right): temp1, temp2, Sampling time.

L1,H1,L2,H2

This data field shows whether the packet was generated by a temperature alarm.

"L1" stands for low temperature alarm,

"H1" stands for high temperature alarm.

"L2" stands for low temperature alarm,

"H2" stands for high temperature alarm.

Payload Analysis:

Device ID(f+IMEI): 355025934932888

SIM Card ID(f+IMSI): 460087023300088

BAT (Battery Info): 3.48V

Signal Strength:

NB-IoT Network signal Strength.

Ex1: 22

0 -113dBm or less

1 -111dBm

2...30 -109dBm... -53dBm

31 -51dBm or greater

99 Not known or not detectable

Interrupt:

This data field shows if this packet is generated by interrupt or not.

Example:

If Json payload is 00 : Normal uplink packet.

If Json payload is 01 : Interrupt Uplink Packet.

L1:

This field indicates the lower limit alarm status for temperature probe 1.

Example:

If Json payload is 00 : No alarm was triggered

If Json payload is 01 : This data packet triggered a lower limit alarm for Temperature 1.

H1:

This field indicates the upper limit alarm status for temperature probe 1.

Example:

If Json payload is 00 : No alarm was triggered

If Json payload is 01 : This data packet triggered the upper limit alarm for temperature 1.

L2:

This field indicates the lower limit alarm status for temperature probe 2.

Example:

If Json payload is 00 : No alarm was triggered

If Json payload is 01 : This data packet triggered a lower limit alarm for Temperature 2.

H2:

This field indicates the upper limit alarm status for temperature probe 2.

Example:

If Json payload is 00 : No alarm was triggered

If Json payload is 01 : This data packet triggered the upper limit alarm for temperature 2.

Latitude:

EX1: 0x00000000 // Locating fails or is not enabled.

EX2: 22.706410 // Latitude: 22.706410

Longitutde:

EX1: 0x00000000 // Locating fails or is not enabled.

EX2: 114.244730 // Longitutde: 114.244730

GPS_Timestamp:

EX1: 0x00000000 // The value is "1970-01-01T00:00:00Z" in JSON format. The initial GPS time is not refreshed if GPS positioning is disabled or fails.

EX2: 2024-07-01 15:23:09

temp1

payload is: 26.7 degree

payload is: -19.3 degrees.

If the value is -327.6, it means the channel1 PT100 probe is not connected.

If the value is -983, it means the PT100 converter is not connected.

temp2

Notice: When using the LTC1-FB module, the temperature2 is invalid and is always 0.0 degrees.

payload is: 27.4 degree

payload is: -19.3 degrees.

If the value is -327.6, it means the channel2 PT100 probe is not connected.

If the value is -983, it means the PT100 converter is not connected.

TimeStamp:

Unit TimeStamp Example: 676b5f85(H) = 1735090053(D)

Put the decimal value into this Epoch Converter to get the time.

3. Configure LTC1/LTC2-FB

3.1 Configure Methods

LTC1/LTC2-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

note

Due to limitations of the NRF9151-NGFF module, the serial communication function remains active for only 5 minutes. If this time is exceeded, you must press the ACT button once to reactivate the chip’s serial communication function.

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), -FB nodes only support lowercase letters.

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+<CMD>? : Help on <CMD>

AT+<CMD> : Run <CMD>

AT+<CMD>=<value> : Set the value

AT+<CMD>=? : Get the value

General Commands

AT+MODEL : Get module information

ATZ : Trig a reset of the MCU

AT+DEUI : Get or set the Device ID

AT+SLEEP : Get or set the sleep status

AT+DEBUG : Set more info output

AT+SERVADDR: Get or Set the Server address

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

AT+APN : Get or set the APN

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

AT+RXDL : Get or Set the receiving time

AT+DNSCFG : Get or Set DNS Server

AT+SFNT : Get or Set the time to join the network

AT+BKDNS : Get or Set dynamic domain name resolution IP

AT+GDNS : Get or Set the DNS

AT+TLSMOD : Get or Set the TLS mode

AT+IPTYPE : Set the IPv4 or IPv6

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

AT+CLOCKLOG: Enable or Disable Clock Logging

AT+TIMESTAMP : Get or Set UNIX timestamp in second

AT+DOWNTE: Get or set the conversion between the standard version and 1T version downlinks

AT+QSW : Power on and power off BG95 module

AT+QBAND: Get or set Frequency Band

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

AT+WMOD : Get or Set the Alarm Mode

AT+ALARM : Get or Set the Alarm Threshold

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

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+GETSENSORVALUE : Returns the current sensor measurement

AT+GETLOG : Print serial port logs

AT+CFG : Print all settings

ATZ : Trig a reset of the MCU

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: ATZ

Downlink Commands: 0x04FF

3.7 Trigger an uplink by external interrupt

LTC1/LTC2-FB has an external trigger interrupt function. Users can use the GPIO_EXTI 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

3.8 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

3.9 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 5 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: 0x03

Format: Command Code (0x03) followed by 5 bytes.

• Example 1: Downlink Payload: 03 01 FFFF 0F 08 // Set SHT record time: AT+CLOCKLOG=1,65535,15,8
• Example 2: Downlink Payload: 03 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.

3.10 Set the TLS mode

Refer to this link (MQTT Connection to send data to MQTT platformto 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 search network time

Feature: Get or Set the time to join the network(unit: minutes).

AT Command: AT+SFNT

Example: AT+SFNT=10 // Set the search time to 10 minutes.

Downlink command: 0x13

Format: Command Code (0x13) followed by 1 byte.

Example: Downlink Payload: 13 0A// AT+SFNT=10

3.12 Set Alarm Threshold

Feature: Set Alarm Threshold. (Unit: ℃)

AT Command: AT+ALARM

The first parameter sets the low limit of channel 1, and the second parameter sets the high limit of channel 1.

The third parameter sets the low limit for channel 2, and the fourth parameter sets the high limit for channel 2.

Example:

• AT+ALARM=-200,800,-200,800 // Channel 1 & Channel 2 operating temp: -200℃~800℃，alarm when out of range.
• AT+ALARM=10,100,10,101 // Channel 1 operating temp: 10℃~100℃; Channel 2 operating temp: 10℃~101℃, alarm when out of range.

Downlink Command: 0x08

Format: Command Code (0x08) followed by 8 bytes.

Each two bytes after the function code 0xA7 is a parameter, corresponding to the four parameters of AT+ALARM in sequence.

Example:

• Downlink payload: 0x08FF380320FF380320 // Same as AT+ALARM=-200,800,-200,800
• Downlink payload: 0x08000A0064000A0065 // Same as AT+ALARM=10,100,10,101

Note: For negative temperature -200℃: 65536-200= 65336(D) = 0XFF38(H)

3.13 Factory data reset

Two different restore factory Settings configurations.

AT command:

• AT+FDR// Reset Parameters to Factory Default.

3.14 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

3.15 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

3.16 Set GPS 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

3.17 Uplink log query

• AT command: AT+GETLOG

This command can be used to query upstream logs of data packets.

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 Configure Network Category to be Searched for under LTE RAT.

NOTE

By default, the NB-IoT network is turned off, and only the LTE-M network is enabled. If a user needs to use the NB-IoT network, they must enable it themselves.

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.

4. Battery & Power Consumption

LTC1/LTC2-FB use ER26500 + SPC1520 battery pack and LTC1/LTC2-FS use 3000mAh Recharable Battery with Solar Panel. See below link for detail information about the battery info and how to replace.

NOTE

To be updated

5. Firmware update

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

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=1,"http://repo.dragino.com/release/NB/LTC2-FB.bin

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

5.2 Firmware Update via J-Link Interface

Use this method if OTA is not available or if the device is unresponsive.

Prerequisites:

• An ARM emulator (J-Link compatible)
• Firmware update tool: nRF Connect for Desktop
• Firmware: LTC1&LTC2-FB/FS

Note: During the installation of nRF Connect for Desktop, you will be prompted to install the J-Link driver. You must confirm the installation; otherwise, the J-Link external tool will not be recognized.

5.2.1 Hardware Connection

Remove the NRF9151 module from the motherboard and connect it to the J-Link as illustrated below:

NRF9151 Module Hardware Wiring:

5.2.2 Software Setup

Launch nRF Connect for Desktop.

Locate and download the Programmer tool from the available apps (see below):

After download, click OPEN to enter the Programmer interface.

5.2.3 Firmware Update Steps

Click "SELECT DEVICE" → Select "J-Link"

On the main screen, click "Add file", then click "Browse" and select the firmware you want to update in the pop-up window.

Click “Erase & Write” to begin the update

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 General Manual for -FB , -FS models

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

6.3 How do users connect custom PT100 sensors?

1. The user needs to cut off one end of the original probe and peel off the wire core.

2. Connect according to the corresponding positive and negative poles.

6.4 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)

6.5 How to fix the FT -- Flat Type probe to surface?

6.6 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

Notice: This part number doesn't include the Temperature sensor. Users need to purchase separately.

Part Number: LTC1-FB/FS-XX or LTC2-FB/FS-XX

XX:

• GE: General version ( Exclude SIM card)

• 1T: with 1NCE * 10 years 500MB SIM card and Pre-configure to ThingsEye server

Probe Options: DR-SI, DR-LT, DR-HT, DR-FSA, DR-FT

8. Packing Info

Package Includes:

• LTC1/LTC2-FB -- NB-IoT/LTE-M Temperature Transmitter x 1

Dimension and weight:

• Device Size: cm
• Device Weight: g
• Package Size / pcs : cm
• Weight / pcs : g

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.com