Table of Contents:

• 1.  Introduction
  • 1.1 ​ What is LTC2-LB LoRaWAN Temperature Transmitter
  • ​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
  • 1.9  Mechanical
  • 1.10  Probe Variant
• 2.  How to use LTC2-LB?
  • 2.1  How it works?
  • 2.2  ​Quick guide to connect to LoRaWAN server (OTAA)
  • 2.3  ​Uplink Payload
    • 2.3.1  Device Status, FPORT=5
    • 2.3.2  Sensor Data. FPORT=2
      • Battery
      • Interrupt flag & Interrupt Level & TEMP1H flag & TEMP1L flag& TEMP2H flag & TEMP2L flag
      • Channel 1 temperature
      • Channel 2 temperature
  • 2.5  Datalog Feature
    • 2.5.1  Ways to get datalog via LoRaWAN
    • 2.5.2  Unix TimeStamp
    • 2.5.3  Set Device Time
    • 2.5.4  Poll sensor value
    • 2.5.5  Datalog Uplink payload
• 3.  Configure LTC2-LB via AT Command or LoRaWAN Downlink
  • 3.1  Set Transmit Interval Time
  • 3.2  Set alarm mode
  • 3.3  Alarm check time
  • 3.4  Set Alarm Threshold
  • 3.5  Print data entries base on page
  • 3.6  Print last few data entries
  • 3.7  Clear Flash Record
  • 3.8  Auto Send None-ACK messages
• 4.  Battery & Power Consumption
• 5.  OTA Firmware update
• 6.  FAQ
  • 6.1  How to use AT Command to configure LTC2-LB
• 7.  Trouble Shooting
  • 7.1  AT Command input doesn't work
• 8.  Order Info
• 9. ​ Packing Info
• 10.  ​Support

1.  Introduction

1.1 ​ What is LTC2-LB LoRaWAN Temperature Transmitter

The Dragino LTC2-LB Industrial LoRaWAN Temperature Transmitter is designed to monitor temperature for different environment. It supports to read PT100 probe and convert the value to temperature and uplink to IoT server via LoRaWAN protocol.

LTC2-LB supports Datalog feature. User can retrieve the sensor value via LoRaWAN downlink command.

LTC2-LB has two internal 24-bit ADC interfaces.

LTC2-LB supports BLE configure and wireless OTA update which make user easy to use.

LTC2-LB is powered by 8500mAh Li-SOCI2 battery, it is designed for long-term use up to several years.

Each LTC2-LB is pre-load with a set of unique keys for LoRaWAN registrations, register these keys to local LoRaWAN server and it will auto-connect after power on.

​1.2  Features

• LoRaWAN v1.0.3 Class A
• max: 2 x monitor temperature channels
• Support 3 -wire PT-100
• Temperature alarm
• Datalog Feature
• Support Bluetooth v5.1 and LoRaWAN remote configure
• Support wireless OTA update firmware
• Uplink on periodically
• Downlink to change configure
• 8500mAh Li/SOCl2 Battery

1.3  Specification

Common DC Characteristics:

• Supply Voltage: Built-in Battery , 2.5v ~ 3.6v
• Operating Temperature: -40 ~ 85°C

LoRa Spec:

• Frequency Range,  Band 1 (HF): 862 ~ 1020 Mhz
• Max +22 dBm constant RF output vs.
• RX sensitivity: down to -139 dBm.
• Excellent blocking immunity

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

• Sleep Mode: 5uA @ 3.3v
• LoRa Transmit Mode: 125mA @ 20dBm, 82mA @ 14dBm

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 LoRaWAN activate. This mode is used for storage and shipping to save battery life.

Working Mode: In this mode, Sensor will work as LoRaWAN Sensor to Join LoRaWAN 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

1.7  BLE connection

LTC2-LB supports BLE remote configure.

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

1.9  Mechanical

1.10  Probe Variant

LTC2-LB provide default probe version. See below for the variant:

2.  How to use LTC2-LB?

2.1  How it works?

2.2  ​Quick guide to connect to LoRaWAN server (OTAA)

Following is an example for how to join the TTN v3 LoRaWAN Network. Below is the network structure; we use the LPS8v2  as a LoRaWAN gateway in this example. 

The LPS8V2 is already set to connected to TTN network , so what we need to now is configure the TTN server.

Step 1: Create a device in TTN with the OTAA keys from LTC2-LB.

Each LTC2-LB is shipped with a sticker with the default device EUI as below:

You can enter this key in the LoRaWAN Server portal. Below is TTN screen shot:

Create the application.

Add devices to the created Application.

Enter end device specifics manually.

Add DevEUI and AppKey.

Customize a platform ID for the device.

Step 2: Add decoder

In TTN, user can add a custom payload so it shows friendly reading.

Click this link to get the decoder: https://github.com/dragino/dragino-end-node-decoder/tree/main/

Below is TTN screen shot:

Step 3: Activate on LTC2-LB

Press the button for 5 seconds to activate the LTC2-LB.

Green led will fast blink 5 times, device will enter OTA mode for 3 seconds. And then start to JOIN LoRaWAN network. Green led will solidly turn on for 5 seconds after joined in network.

After join success, it will start to upload messages to TTN and you can see the messages in the panel.

2.3  ​Uplink Payload

2.3.1  Device Status, FPORT=5

Users can use the downlink command(0x26 01) to ask LTC2-LB to send device configure detail, include device configure status. LTC2-LB will uplink a payload via FPort=5 to server.

The Payload format is as below.

Example in TTN: 

Sensor Model: For LTC2-LB, this value is 0x3D

Firmware Version: 0x0100, Means: v1.0.0 version

Frequency Band:

0x01: EU868

0x02: US915

0x03: IN865

0x04: AU915

0x05: KZ865

0x06: RU864

0x07: AS923

0x08: AS923-1

0x09: AS923-2

0x0a: AS923-3

0x0b: CN470

0x0c: EU433

0x0d: KR920

0x0e: MA869

Sub-Band:

AU915 and US915:value 0x00 ~ 0x08

CN470: value 0x0B ~ 0x0C

Other Bands: Always 0x00

Battery Info:

Check the battery voltage.

Ex1: 0x0B45 = 2885mV

Ex2: 0x0B49 = 2889mV

2.3.2  Sensor Data. FPORT=2

Below is the uplink payload which shows.

Example in TTN: 

Example:

If payload is: 0105H:  (0105 & 8000 == 0), temp = 0105H /10 = 26.1 degree

If payload is: FF3FH :  (FF3F & 8000 == 1) , temp = (FF3FH - 65536)/10 = -19.3 degrees.

(FF3F & 8000：Judge whether the highest bit is 1, when the highest bit is 1, it is negative)

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.

​​​​

2.5  Datalog Feature

LTC2-LB will auto get the time from LoRaWAN server during Join, and each uplink will then include a timestamp. When user want to retrieve sensor value, user can send a poll command from the IoT platform to ask sensor to send value in the required time slot.

2.5.1  Ways to get datalog via LoRaWAN

There are two methods:

Method 1: IoT Server sends a downlink LoRaWAN command to poll the value for specified time range.

Method 2: Set PNACKMD=1, LTC2-LB will wait for ACK for every uplink, when there is no LoRaWAN network, LTC2-LB will mark these records with non-ack messages and store the sensor data, and it will send all messages (10s interval) after the network recovery.

Note for method 2:

• a) LTC2-LB will do an ACK check for data records sending to make sure every data arrive server.
• b) LTC2-LB will send data in CONFIRMED Mode when PNACKMD=1, but LTC2-LB won't re-transmit the packet if it doesn't get ACK, it will just mark it as a NONE-ACK message. In a future uplink if LTC2-LB gets a ACK, LTC2-LB will consider there is a network connection and resend all NONE-ACK Message. 

Below is the typical case for the auto-update datalog feature (Set PNACKMD=1)

2.5.2  Unix TimeStamp

LTC2-LB uses Unix TimeStamp format based on

Users can get this time from the link:  https://www.epochconverter.com/ :

Below is the converter example

2.5.3  Set Device Time

2.5.4  Poll sensor value

Users can poll sensor values based on timestamps. Below is the downlink command.

2.5.5  Datalog Uplink payload

When server senser a datalog polling to LTC2-LB, LTC2-LB will reply with one or more uplink messages as reply. Each uplink message includes multiply data entries value. Each entry has the same payload format as normal uplink payload.

Note:

• Poll Message Flag is set to 1.
• Each data entry is 11 bytes, to save airtime and battery, devices will send max bytes according to the current DR and Frequency bands.

For example, in US915 band, the max payload for different DR is:

1. DR0: max is 11 bytes so one entry of data
2. DR1: max is 53 bytes so devices will upload 4 entries of data (total 44 bytes)
3. DR2: total payload includes 11 entries of data
4. DR3: total payload includes 22 entries of data.

If devise doesn't have any data in the polling time. Device will uplink 11 bytes of 0    

Example:

If LTC2-LB has below data inside Flash:

If user send below downlink command: 3166DBFFCC66DC00F80A

Where : Start time: 66DBFFCC = time 2024/9/7 15:25:00

              Stop time: 66DC00F8 = time 2024/9/7 15:30:00

LTC2-LB will uplink this payload.

000000F700FC4266DBFFD0 000000F700FC4266DC000C 000000F700FB4266DC0048 000000F700FB4266DC0084 000000F800FC4266DC00C0

Where the first 11 bytes is for the first entry:

0000 00F7 00FC 42 66DBFFD0

0x0000: The first two bytes are reserved positions and have no meaning.

0x00F7: Channel 2 temp=0x00F7/10=24.7℃

0x00FC: Channel 1 temp=0x0FC/10=25.2℃

0x42: Interrupt flag & Interrupt Level:       

• If payload & 0x02 = 0x02  --> The interrupt Level is "High";
• If payload & 0x02 = 0x00  --> The interrupt Level is "Low";
• If payload & 0x01 = 0x01  --> The interrupt flag is "Ture";
• If payload & 0x01 = 0x00  --> The interrupt flag is "False";

 0x66DBFFD0: System timestamp=0x66DBFFD0=1725693904(UTC)

Example:

The datalog data is as follows:

000000F700FC4266DBFFD0 000000F700FC4266DC000C 000000F700FB4266DC0048 000000F700FB4266DC0084 000000F800FC4266DC00C0

And the decoding on the server is:

"DATALOG": "[25.2,24.7,High,False,2024-09-07 07:25:04],[25.2,24.7,High,False,2024-09-07 07:26:04],[25.1,24.7,High,False,2024-09-07 07:27:04],[25.1,24.7,High,False,2024-09-07 07:28:04],[25.2,24.8,High,False,2024-09-07 07:29:04],",

Its data format is:

[Temp_Channel1,Temp_Channel2,Interrupt_level,Interrupt_flag,Data_time],[Temp_Channel1,Temp_Channel2,Interrupt_level,Interrupt_flag,Data_time],...

3.  Configure LTC2-LB via AT Command or LoRaWAN Downlink

• AT Command Connection: See FAQ.

• LoRaWAN Downlink instruction for different platforms: IoT LoRaWAN Server

• General system settings like: uplink interval.

• LoRaWAN protocol & radio related command.

​

3.1  Set Transmit Interval Time

Feature: Change LoRaWAN End Node Transmit Interval.

AT Command: AT+TDC

3.2  Set alarm mode

Feature: Enable/Disable Alarm Mode.

AT Command: AT+WMOD

• AT+WMOD=0    //Disable the alarm mode, default.
• AT+WMOD=1    //Enable the alarm mode.

Downlink Command: 0xA5

• Downlink payload: 0xA500         //Same as AT+WMOD=0
• Downlink payload: 0xA501         //Same as AT+WMOD=1

3.3  Alarm check time

Feature: The time interval to check sensor value for Alarm. ( Default: AT+CITEMP=1; Unit: minute )

AT Command: AT+CITEMP

Example: 

• AT+CITEMP=10     //Set collection interval in 10 min, only in alarm mode.

Downlink Command: 0xA6

Format: Command Code (0xA6) followed by 2 bytes.

Example:

• Downlink payload: 0xA6000A     //Same as AT+CITEMP=10

3.4  Set Alarm Threshold

Feature: Set Alarm Threshold. (Unit: ℃)

AT Command: AT+ARTEMP

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

Downlink Command: 0xA7

Format: Command Code (0xA7) followed by 8 bytes.

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

Example:

• Downlink payload: 0xA7FF380320FF380320    //Same as AT+ARTEMP=-200,800,-200,800
• Downlink payload: 0xA7000A0064000A0065   //Same as AT+ARTEMP=10,100,10,101   

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

3.5  Print data entries base on page

Feature: Print the sector data from start page to stop page (max is 400 pages).

AT Command: AT+PDTA

Downlink Command:

No downlink commands for feature

3.6  Print last few data entries

Feature: Print the last few data entries

AT Command: AT+PLDTA

Downlink Command:

No downlink commands for feature

3.7  Clear Flash Record

Feature: Clear flash storage for data log feature.

AT Command: AT+CLRDTA

Downlink Command: 0xA3

• Example: 0xA301     //  Same as AT+CLRDTA

3.8  Auto Send None-ACK messages

Feature: LTC2-LB will wait for ACK for each uplink, If LTC2-LB doesn't get ACK from the IoT server, it will consider the message doesn't arrive server and store it. LTC2-LB keeps sending messages in normal periodically. Once LTC2-LB gets ACK from a server, it will consider the network is ok and start to send the not-arrive message.

AT Command: AT+PNACKMD

The default factory setting is 0

Downlink Command: 0x34

• Example: 0x3401       //  Same as AT+PNACKMD=1

4.  Battery & Power Consumption

LTC2-LB uses ER26500 + SPC1520 battery pack. See below link for detail information about the battery info and how to replace.

Battery Info & Power Consumption Analyze .

5.  OTA Firmware update

User can change firmware LTC2-LB to:

• Change Frequency band/ region.
• Update with new features.
• Fix bugs. 

6.  FAQ

6.1  How to use AT Command to configure LTC2-LB

LTC2-LB supports AT Command set. User can use a USB to TTL adapter plus the Program Cable to connect to LTC2-LB for using AT command, as below.

Connection:

• USB to TTL GND <-->  LTC2-LB GND

• USB to TTL RXD  <-->  LTC2-LB TXD

• USB to TTL TXD  <-->  LTC2-LB RXD

7.  Trouble Shooting

7.1  AT Command input doesn't work

In the case if user can see the console output but can't type input to the device. Please check if you already include the ENTER while sending out the command. Some serial tool doesn't send ENTER while press the send key, user need to add ENTER in their string. 

8.  Order Info

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

Part Number : LTC2-LB-XX

XX: The default frequency band

• AS923 : LoRaWAN AS923 band
• AU915 : LoRaWAN AU915 band
• EU433 : LoRaWAN EU433 band
• EU868 : LoRaWAN EU868 band
• KR920 : LoRaWAN KR920 band
• US915 : LoRaWAN US915 band
• IN865 :  LoRaWAN IN865 band
• CN470 : LoRaWAN CN470 band

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

9. ​ Packing Info

Package Includes:

• LTC2-LB LoRaWAN Temperature Transmitter x 1

Dimension and weight:

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

10.  ​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.