Table of Contents:

• 1. Introduction
  • 1.1 What is the LT-22222-L I/O Controller?
  • 1.2 Specifications
  • 1.3 Features
  • 1.4 Applications
  • 1.5 Hardware Variants
• 2. Assembling the device
  • 2.1 Connecting the antenna
  • 2.2 Terminals
  • 2.3 Connecting LT-22222-L to a Power Source
• 3. Registering LT-22222-L with a LoRaWAN Network Server
  • 3.1 Prerequisites
  • 3.2 The Things Stack
    • 3.2.1 Setting up
      • 3.2.1.1 Using the LoRaWAN Device Repository
      • 3.2.1.2 Adding device manually
    • 3.2.2 Joining
    • 3.2.3 Uplinks
    • 3.2.4 Downlinks
  • 3.3 Working Modes and Uplink Payload formats
    • 3.3.1 AT+MOD=1, 2ACI+2AVI
    • 3.3.2 AT+MOD=2, (Double DI Counting)
    • 3.3.3 AT+MOD=3, Single DI Counting + 2 x ACI
    • 3.3.4 AT+MOD=4, Single DI Counting + 1 x Voltage Counting
    • 3.3.5 AT+MOD=5, Single DI Counting + 2 x AVI + 1 x ACI
    • 3.3.6 AT+ADDMOD=6 (Trigger Mode, Optional)
    • 3.3.7 Payload Decoder
  • 3.4 ​Configure LT-22222-L via AT Commands or Downlinks
    • 3.4.1 Common commands
    • 3.4.2 Sensor-related commands
      • 3.4.2.1 Set Transmit/Uplink Interval
      • 3.4.2.2 Set the Working Mode (AT+MOD)
      • 3.4.2.3 Request an uplink from the device
      • 3.4.2.4 Enable/Disable Trigger Mode
      • 3.4.2.5 Request trigger settings
      • 3.4.2.6 Enable/Disable DI1/DI2/DI3 as a trigger
      • 3.4.2.7 Trigger1 – Set DI or DI3 as a trigger
      • 3.4.2.8 Trigger2 – Set DI2 as a trigger
      • 3.4.2.9 Trigger – Set AC (current) as a trigger
      • 3.4.2.10 Trigger – Set AV (voltage) as trigger
      • 3.4.2.11 Trigger – Set minimum interval
      • 3.4.2.12 DO -- Control Digital Output DO1/DO2/DO3
      • 3.4.2.13 DO -- Control Digital Output DO1/DO2/DO3 with time control
      • 3.4.2.14 Relay -- Control Relay Output RO1/RO2
      • 3.4.2.15 Relay -- Control Relay Output RO1/RO2 with time control
      • 3.4.2.16 Counting -- Voltage threshold counting
      • 3.4.2.17 Counting -- Pre-configure the Count Number
      • 3.4.2.18 Counting -- Clear Counting
      • 3.4.2.19 Counting -- Set Saving Interval for 'Counting Result'
      • 3.4.2.20 Reset saved RO and DO states
      • 3.4.2.21 Encrypted payload
      • 3.4.2.22 Get sensor value
      • 3.4.2.23 Resetting the downlink packet count
      • 3.4.2.24 When the limit bytes are exceeded, upload in batches
      • 3.4.2.25 Copy downlink to uplink
      • 3.4.2.26 Query firmware version, frequency band, sub band, and TDC time
  • 3.5 Integrating with ThingsEye.io
    • 3.5.1 Configuring The Things Stack
    • 3.5.2 Configuring ThingsEye.io
      • 3.5.2.1 Viewing integration details
      • 3.5.2.2 Viewing events
      • 3.5.2.3 Deleting an integration
      • 3.5.2.4 Viewing sensor data on a dashboard
  • 3.6 Interface Details
    • 3.6.1 Digital Input Ports: DI1/DI2/DI3 (For LT-33222-L, Low Active)
    • 3.6.2 Digital Input Ports: DI1/DI2
    • 3.6.3 Digital Output Ports: DO1/DO2
    • 3.6.4 Analog Input Interfaces
    • 3.6.5 Relay Output
  • 3.7 LED Indicators
• 4. Using AT Commands
  • 4.1 Connecting the LT-22222-L to a PC
  • 4.2 LT-22222-L related AT commands
  • 4.2 Common AT Command Sequence
    • 4.2.1 Multi-channel ABP mode (Use with SX1301/LG308)
    • 4.2.2 Single-channel ABP mode (Use with LG01/LG02)
    • 4.2.3 Change to Class A
• 5. Case Study
  • 5.1 Counting how many objects pass through the flow line
• 6. FAQ
  • 6.1 How to update the firmware?
  • 6.2 How to change the LoRaWAN frequency band/region?
  • 6.3 How to setup LT-22222-L to work with a Single Channel Gateway, such as LG01/LG02?
  • 6.4 How to change the uplink interval?
  • 6.5 Can I see the counting event in the serial output?
  • 6.6 Can I use point-to-point communication with LT-22222-L?
  • 6.7 Why does the relay output default to an open relay after the LT-22222-L is powered off?
  • 6.8 Can I setup LT-22222-L as a NC (Normally Closed) relay?
  • 6.9 Can the LT-22222-L save the RO state?
  • 6.10 Why does the LT-22222-L always report 15.585V when measuring the AVI?
• 7. Troubleshooting
  • 7.1 Downlink isn't working. How can I solve this?
  • 7.2 Having trouble uploading an image?
  • 7.3 Why can't I join TTN in the US915 /AU915 bands?
  • 7.4 Why can the LT-22222-L perform uplink normally, but cannot receive downlink?
• 8. Ordering information
• 9. Package information
• 10. Support
• 11. Reference​​​​​

1. Introduction

1.1 What is the LT-22222-L I/O Controller?

1.2 Specifications

Hardware System:

• STM32L072xxxx MCU
• SX1276/78 Wireless Chip  
• Power Consumption:
  • Idle: 4mA@12V
  • 20dB Transmit: 34mA@12V
• Operating Temperature: -40 ~ 85 Degrees, No Dew

Interface for Model: LT22222-L:

• 2 x Digital dual direction Input (Detect High/Low signal, Max: 50V, or 220V with optional external resistor)
• 2 x Digital Output (NPN output. Max pull-up voltage 36V,450mA)
• 2 x Relay Output (5A@250VAC / 30VDC)
• 2 x 0~20mA Analog Input (res:0.01mA)
• 2 x 0~30V Analog Input (res:0.01V)
• Power Input 7~ 24V DC.  

LoRa Spec:

• Frequency Range:
  • Band 1 (HF): 862 ~ 1020 MHz
  • Band 2 (LF): 410 ~ 528 MHz
• 168 dB maximum link budget.
• +20 dBm - 100 mW constant RF output vs.
• +14 dBm high-efficiency PA.
• Programmable bit rate up to 300 kbps.
• High sensitivity: down to -148 dBm.
• Bullet-proof front end: IIP3 = -12.5 dBm.
• Excellent blocking immunity.
• Low RX current of 10.3 mA, 200 nA register retention.
• Fully integrated synthesizer with a resolution of 61 Hz.
• FSK, GFSK, MSK, GMSK, LoRaTM and OOK modulation.
• Built-in bit synchronizer for clock recovery.
• Preamble detection.
• 127 dB Dynamic Range RSSI.
• Automatic RF Sense and CAD with ultra-fast AFC.
• Packet engine up to 256 bytes with CRC.

1.3 Features

• LoRaWAN Class A & Class C modes
• Optional Customized LoRa Protocol
• Frequency Bands: CN470/EU433/KR920/US915/EU868/AS923/AU915/RU864/IN865/MA869
• AT Commands to change parameters
• Remotely configure parameters via LoRaWAN Downlink
• Firmware upgradable via program port
• Counting

1.4 Applications

• Smart buildings & home automation
• Logistics and supply chain management
• Smart metering
• Smart agriculture
• Smart cities
• Smart factory

1.5 Hardware Variants

2. Assembling the device

2.1 Connecting the antenna

Connect the LoRa antenna to the antenna connector, ANT, located on the top right side of the device, next to the upper screw terminal block. Secure the antenna by tightening it clockwise.

2.2 Terminals

The  LT-22222-L has two screw terminal blocks. The upper screw treminal block has 6 screw terminals and the lower screw terminal block has 10 screw terminals.

Upper screw terminal block (from left to right):

Lower screw terminal block (from left to right):

2.3 Connecting LT-22222-L to a Power Source

The LT-22222-L I/O Controller can be powered by a 7–24V DC power source. Connect your power supply’s positive wire to the VIN and the negative wire to the GND screw terminals. The power indicator (PWR) LED will turn on when the device is properly powered.

3. Registering LT-22222-L with a LoRaWAN Network Server

The LT-22222-L supports both OTAA (Over-the-Air Activation) and ABP (Activation By Personalization) methods to activate with a LoRaWAN Network Server. However, OTAA is the most secure method for activating a device with a LoRaWAN Network Server. OTAA regenerates session keys upon initial registration and regenerates new session keys after any subsequent reboots. By default, the LT-22222-L is configured to operate in LoRaWAN Class C mode.

3.1 Prerequisites

The LT-22222-L comes with device registration information such as DevEUI, AppEUI, and AppKey that allows you to register it with a LoRaWAN network. These registration information can be found on a sticker that can be found inside the package. Please keep the registration information sticker in a safe place for future reference.

The following subsections explain how to register the LT-22222-L with different LoRaWAN network server providers.

3.2 The Things Stack

This section guides you through how to register your LT-22222-L with The Things Stack Sandbox.

The network diagram below illustrates the connection between the LT-22222-L and The Things Stack, as well as how the data can be integrated with the ThingsEye IoT platform.

3.2.1 Setting up

• Sign up for a free account with The Things Stack Sandbox if you do not have one yet.
• Log in to your The Things Stack Sandbox account.
• Create an application with The Things Stack if you do not have one yet (E.g., dragino-docs).
• Go to your application's page and click on the End devices in the left menu.
• On the End devices page, click on + Register end device. Two registration options are available:

3.2.1.1 Using the LoRaWAN Device Repository

• On the Register end device page:
  • Select the option Select the end device in the LoRaWAN Device Repository under Input method.
  • Select the End device brand, Model, Hardware version, Firmware version, and Profile (Region) from the respective dropdown lists.
    • End device brand: Dragino Technology Co., Limited
    • Model: LT22222-L I/O Controller
    • Hardware ver: Unknown
    • Firmware ver: 1.6.0 
    • Profile (Region): Select the region that matches your device.
  • Select the Frequency plan that matches your device from the Frequency plan dropdown list.

• Register end device page continued...
  • Enter the AppEUI in the JoinEUI field and click the Confirm button. If The Things Stack accepts the JoinEUI you provided, it will display the message 'This end device can be registered on the network'.
  • In the DevEUI field, enter the DevEUI.
  • In the AppKey field, enter the AppKey.
  • In the End device ID field, enter a unique name for your LT-22222-N within this application.
  • Under After registration, select the View registered end device option.

3.2.1.2 Adding device manually

• On the Register end device page:
  • Select the option Enter end device specifies manually under Input method.
  • Select the Frequency plan that matches your device from the Frequency plan dropdown list.
  • Select the LoRaWAN version as LoRaWAN Specification 1.0.3
  • Select the Regional Parameters version as RP001 Regional Parameters 1.0.3 revision A
  • Click Show advanced activation, LoRaWAN class and cluster settings link to expand the hidden section.
  • Select the option Over the air activation (OTAA) under the Activation mode.
  • Select Class C (Continuous) from the Additional LoRaWAN class capabilities dropdown list.

• Register end device page continued...
  • Enter the AppEUI in the JoinEUI field and click the Confirm button. If The Things Stack accepts the JoinEUI you provided, it will display the message 'This end device can be registered on the network'
  • In the DevEUI field, enter the DevEUI.
  • In the AppKey field, enter the AppKey.
  • In the End device ID field, enter a unique name for your LT-22222-N within this application.
  • Under After registration, select the View registered end device option.
  • Click the Register end device button.

You will be navigated to the Device overview page.

3.2.2 Joining

On the end device's page (in this case, lt-22222-l), click on Live data tab. The Live data panel for your device will display. Initially, it is blank.

Now power on your LT-22222-L. The TX LED will fast-blink 5 times which means the LT-22222-L will enter the work mode and start to join The Things Stack network server. The TX LED will be on for 5 seconds after joining the network. In the Live data panel, you can see the join-request and join-accept messages exchanged between the device and the network server.

3.2.3 Uplinks

After successfully joining, the device will send its first uplink data message to The Things Stack application it belongs to (in this example, it is dragino-docs). When the LT-22222-L sends an uplink message to the server, the TX LED turns on for 1 second. By default, you will receive an uplink data message from the device every 10 minutes.

Click on one of a Forward uplink data messages to see its payload content. The payload content is encapsulated within the decode_payload {} JSON object.

If you can't see the decoded payload, it is because you haven't added the uplink formatter code. To add the uplink formatter code, select Applications > [your application] > End devices > [your  end device] > Payload formatters > Uplink. Then  select Use Device repository formatters for the Formatter type dropdown. Click the Save changes button to apply the changes.

We have written a payload formatter that resolves some decoding issues present in The Things Stack Device Repository payload formatter. You can add it under the Custom JavaScript formatter. It can be found here:

3.2.4 Downlinks

When the LT-22222-L receives a downlink message from the LoRaWAN Network Server, the RX LED turns on for 1 second.

3.3 Working Modes and Uplink Payload formats

The LT-22222-L has 5 working modes. It also has an interrupt/trigger mode for different types of applications that can be used together with any working mode as an additional feature. The default mode is MOD1 and you can switch between these modes using AT commands.

• MOD1: (default mode/factory set): 2ACI + 2AVI + DI + DO + RO

• MOD2: Double DI Counting + DO + RO

• MOD3: Single DI Counting + 2 x ACI + DO + RO

• MOD4: Single DI Counting + 1 x Voltage Counting + DO + RO

• MOD5: Single DI Counting + 2 x AVI + 1 x ACI + DO + RO

• ADDMOD6: Trigger Mode, Optional, used together with MOD1 ~ MOD5

The uplink messages are sent over LoRaWAN FPort=2. By default, an uplink message is sent every 10 minutes. 

3.3.1 AT+MOD=1, 2ACI+2AVI

• RO is for the relay. ROx=1: CLOSED, ROx=0 always OPEN.
• DI is for digital input. DIx=1: HIGH or FLOATING, DIx=0: LOW.
• DO is for reverse digital output. DOx=1: LOW, DOx=0: HIGH or FLOATING.

Note: DI3 and DO3 bits are not valid for LT-22222-L

For example, if the payload is: 

The interface values can be calculated as follows:  

AVI1 channel voltage is 0x04AB/1000=1195(DEC)/1000=1.195V

AVI2 channel voltage is 0x04AC/1000=1.196V

ACI1 channel current is 0x1310/1000=4.880mA

ACI2 channel current is 0x1300/1000=4.864mA

The last byte 0xAA= 10101010(b) means,

• [1] The RO1 relay channel is CLOSED, and the RO1 LED is ON.
• [0] The RO2 relay channel is OPEN, and the RO2 LED is OFF.
• [1] DI3 - not used for LT-22222-L.
• [0] DI2 channel input is LOW, and the DI2 LED is OFF.
• [1] DI1 channel input state:
  • DI1 is FLOATING when no sensor is connected between DI1+ and DI1-.
  • DI1 is HIGH when a sensor is connected between DI1- and DI1+ and the sensor is ACTIVE.
  • DI1 LED is ON in both cases.
• [0] DO3 - not used for LT-22222-L.
• [1] DO2 channel output is LOW, and the DO2 LED is ON.
• [0] DO1 channel output state:
  • DO1 is FLOATING when there is no load between DO1 and V+.
  • DO1 is HIGH and there is a load between DO1 and V+.
  • DO1 LED is OFF in both cases.

Reserve = 0

MOD = 1

3.3.2 AT+MOD=2, (Double DI Counting)

• FIRST: Indicates that this is the first packet after joining the network.
• DO is for reverse digital output. DOx=1: LOW, DOx=0: HIGH or FLOATING.

3.3.3 AT+MOD=3, Single DI Counting + 2 x ACI

Note: The maximum count depends on the bytes it is.
The maximum count for four bytes is FFFFFFFF (hex) = 4294967295 (dec).
It starts counting again when it reaches the maximum value.

LT22222-L: In this mode, the DI1 is used as a counting pin.

• RO is for the relay. ROx=1: closed, ROx=0 always open.
• FIRST: Indicates that this is the first packet after joining the network.
• DO is for reverse digital output. DOx=1: output low, DOx=0: high or floating.

3.3.4 AT+MOD=4, Single DI Counting + 1 x Voltage Counting

Note:The maximum count depends on the bytes it is.
The maximum count for four bytes is FFFFFFFF (hex) = 4294967295 (dec).
It starts counting again when it reaches the maximum value.

• RO is for the relay. ROx=1: closed, ROx=0 always open.
• FIRST: Indicates that this is the first packet after joining the network.
• DO is for reverse digital output. DOx=1: output low, DOx=0: high or floating.

3.3.5 AT+MOD=5, Single DI Counting + 2 x AVI + 1 x ACI

Note:The maximum count depends on the bytes it is.
The maximum count for four bytes is FFFFFFFF (hex) = 4294967295 (dec).
It starts counting again when it reaches the maximum value.

LT22222-L: In this mode, the DI1 is used as a counting pin.

• RO is for the relay. ROx=1: closed, ROx=0 always open.
• FIRST: Indicates that this is the first packet after joining the network.

• DO is for reverse digital output. DOx=1: output low, DOx=0: high or floating.

3.3.6 AT+ADDMOD=6 (Trigger Mode, Optional)

This mode is optional and intended for trigger purposes. It can operate alongside with other modes.

For example, if you configure the following commands:

• AT+MOD=1             -->   Sets the default working mode
• AT+ADDMOD6=1   -->   Enables trigger mode

The LT-22222-L will continuously monitor AV1, AV2, AC1, and AC2 every 5 seconds. It will send uplink packets in two cases:

1. Periodic uplink: Based on TDC time. The payload is the same as in normal mode (MOD=1 as set above). These are unconfirmed uplinks.

2. Trigger uplink: sent when a trigger condition is met. In this case, LT will send two packets

   • The first uplink uses the payload specified in trigger mode (MOD=6). 
   • The second packet uses the normal mode payload (MOD=1 as set above). Both are confirmed uplinks.

AT Commands to set Trigger Conditions:

Trigger based on voltage:

Format: AT+AVLIM=<AV1_LIMIT_LOW>,< AV1_LIMIT_HIGH>,<AV2_LIMIT_LOW>,< AV2_LIMIT_HIGH>

Example:

AT+AVLIM=3000,6000,0,2000 (triggers an uplink if AVI1 voltage is lower than 3V or higher than 6V, or if AV2 voltage is higher than 2V)

AT+AVLIM=5000,0,0,0 (triggers an uplink if AVI1 voltage lower than 5V. Use 0 for parameters that are not in use)

Trigger based on current:

Format: AT+ACLIM=<AC1_LIMIT_LOW>,< AC1_LIMIT_HIGH>,<AC2_LIMIT_LOW>,< AC2_LIMIT_HIGH>

Example:

AT+ACLIM=10000,15000,0,0 (triggers an uplink if AC1 current is lower than 10mA or higher than 15mA)

Trigger based on DI status:

DI status triggers Flag.

Format: AT+DTRI=<DI1_TIRGGER_FlAG>,< DI2_TIRGGER_FlAG >

Example:

AT+ DTRI =1,0   (Enable DI1 trigger / disable DI2 trigger)

LoRaWAN Downlink Commands for Setting the Trigger Conditions:

Type Code: 0xAA. Downlink command same as AT Command AT+AVLIM, AT+ACLIM

Format: AA xx yy1 yy1 yy2 yy2 yy3 yy3 yy4 yy4

  AA: Type Code for this downlink Command:

  xx: 0: Limit for AV1 and AV2; 1: limit for AC1 and AC2; 2: DI1and DI2 trigger enable/disable.

  yy1 yy1: AC1 or AV1 LOW limit or DI1/DI2 trigger status.

  yy2 yy2: AC1 or AV1 HIGH limit.

  yy3 yy3: AC2 or AV2 LOW limit.

  Yy4 yy4: AC2 or AV2 HIGH limit.

Example 1: AA 00 13 88 00 00 00 00 00 00

Same as AT+AVLIM=5000,0,0,0 (triggers an uplink if AVI1 voltage is lower than 5V. Use 0s for parameters that are not in use)

Example 2: AA 02 01 00

Same as AT+ DTRI =1,0 (Enable DI1 trigger / disable DI2 trigger)

Trigger Settings Payload Explanation:

MOD6 Payload: total of 11 bytes

TRI FLAG1 is a combination to show if the trigger is set for this part. Totally 1 byte as below

• Each bit shows if the corresponding trigger has been configured.

Example:

10100000: This means the system is configured to use the triggers AV1_LOW and AV2_LOW.

TRI Status1 is a combination to show which condition is trigger. Totally 1 byte as below

• Each bit shows which status has been triggered on this uplink.

Example:

10000000: The uplink is triggered by AV1_LOW, indicating that the voltage is too low.

TRI_DI FLAG+STA is a combination to show which condition is trigger. Totally 1byte as below

• Each bit shows which status has been triggered on this uplink.

Example:

00000111: This means both DI1 and DI2 triggers are enabled, and this packet is trigger by DI1.

00000101: This means both DI1 and DI2 triggers are enabled.

Enable/Disable MOD6 : 0x01: MOD6 is enabled. 0x00: MOD6 is disabled.

Downlink command to poll/request MOD6 status:

AB 06

When device receives this command, it will send the MOD6 payload.

3.3.7 Payload Decoder

3.4 ​Configure LT-22222-L via AT Commands or Downlinks

• Common commands:

• Sensor-related commands:

3.4.1 Common commands

3.4.2 Sensor-related commands

These commands are specially designed for the LT-22222-L. Commands can be sent to the device using options such as an AT command or a LoRaWAN downlink payload. 

3.4.2.1 Set Transmit/Uplink Interval

Sets the uplink interval of the device. The default uplink transmission interval is 10 minutes.

AT command

Downlink payload

3.4.2.2 Set the Working Mode (AT+MOD)

Sets the working mode.

AT command

Downlink payload

3.4.2.3 Request an uplink from the device

Requests an uplink from LT-22222-L. The content of the uplink payload varies based on the device's current working mode.

AT command

There is no AT Command available for this feature.

Downlink payload

3.4.2.4 Enable/Disable Trigger Mode

Enable or disable the trigger mode for the current working mode (see also ADDMOD6).

AT Command

Downlink payload

3.4.2.5 Request trigger settings

Requests the trigger settings.

AT Command:

There is no AT Command available for this feature.

Downlink Payload

3.4.2.6 Enable/Disable DI1/DI2/DI3 as a trigger

Enable or disable DI1/DI2/DI3 as a trigger.

AT Command

Downlink Payload

3.4.2.7 Trigger1 – Set DI or DI3 as a trigger

Sets DI1 or DI3 (for LT-33222-L) as a trigger.

AT Command

Downlink Payload

3.4.2.8 Trigger2 – Set DI2 as a trigger

Sets DI2 as a trigger.

AT Command

Downlink Payload

3.4.2.9 Trigger – Set AC (current) as a trigger

Sets the current trigger based on the AC port. See also trigger mode

AT Command

Downlink Payload

3.4.2.10 Trigger – Set AV (voltage) as trigger

Sets the current trigger based on the AV port. See also trigger mode

AT Command

Downlink Payload

3.4.2.11 Trigger – Set minimum interval

Sets the AV and AC trigger minimum interval. The device won't respond to a second trigger within this set time after the first trigger.

AT Command

Downlink Payload

3.4.2.12 DO -- Control Digital Output DO1/DO2/DO3

Controls the digital outputs DO1, DO2, and DO3

AT Command

There is no AT Command to control the Digital Output.

Downlink Payload

3.4.2.13 DO -- Control Digital Output DO1/DO2/DO3 with time control

AT command

There is no AT command to control the digital output.

Downlink payload

3.4.2.14 Relay -- Control Relay Output RO1/RO2

AT Command:

There is no AT Command to control the Relay Output.

Downlink Payload

3.4.2.15 Relay -- Control Relay Output RO1/RO2 with time control

Controls the relay output time.

AT Command:

There is no AT Command to control the Relay Output

Downlink Payload (prefix 0x05):

0x05 aa bb cc dd      // Sets RO1/RO2 relays with time control

This controls the relay output time and includes 4 bytes:

First byte : Type code (0x05)

Second byte (aa): Inverter Mode

01: Relays will change back to their original state after timeout.

00: Relays will change to the inverter state after timeout.

Third byte (bb): Control Method and Ports status:

Fourth/Fifth/Sixth/Seventh bytes (cc): Latching time. Unit: ms

Note:

   Since firmware v1.6.0, the latch time supports both 4 bytes and 2 bytes.

   Before firmware v1.6.0, the latch time only supported 2 bytes.

The device will uplink a packet if the downlink code executes successfully.

Example payload:

1. 05 01 11 07 D0

Relay1 and Relay2 will be set to NC, lasting 2 seconds, then revert to their original state

2. 05 01 10 07 D0

Relay1 will change to NC, Relay2 will change to NO, lasting 2 seconds, then both will revert to their original state.

3. 05 00 01 07 D0

Relay1 will change to NO, Relay2 will change to NC, lasting 2 seconds, then Relay1 will change to NC, and Relay2 will change to NO.

4. 05 00 00 07 D0

Relay1 and Relay2 will change to NO, lasting 2 seconds, then both will change to NC.

3.4.2.16 Counting -- Voltage threshold counting

When the voltage exceeds the threshold, counting begins. For details, see MOD4

AT Command

Downlink Payload

3.4.2.17 Counting -- Pre-configure the Count Number

This command allows users to pre-configure specific count numbers for various counting parameters such as Count1, Count2, or AVI1 Count. Use the AT command to set the desired count number for each configuration.

AT Command

Downlink Payload

3.4.2.18 Counting -- Clear Counting

This command clears the counting in counting mode.

AT Command

Downlink Payload

3.4.2.19 Counting -- Set Saving Interval for 'Counting Result'

This command allows you to configure the device to save its counting result to internal flash memory at specified intervals. By setting a save time, the device will periodically store the counting data to prevent loss in case of power failure. The save interval can be adjusted to suit your requirements, with a minimum value of 30 seconds.

AT Command

Downlink Payload

3.4.2.20 Reset saved RO and DO states

This command allows you to reset the saved relay output (RO) and digital output (DO) states when the device joins the network. By configuring this setting, you can control whether the device should retain or reset the relay states after a reset and rejoin to the network.

AT Command

Downlink Payload

3.4.2.21 Encrypted payload

This command allows you to configure whether the device should upload data in an encrypted format or in plaintext. By default, the device encrypts the payload before uploading. You can toggle this setting to either upload encrypted data or transmit it without encryption.

AT Command:

There is no downlink payload for this configuration.

3.4.2.22 Get sensor value

This command allows you to retrieve and optionally uplink sensor readings through the serial port.

AT Command

There is no downlink payload for this configuration.

3.4.2.23 Resetting the downlink packet count

This command manages how the node handles mismatched downlink packet counts. It offers two modes: one disables the reception of further downlink packets if discrepancies occur, while the other resets the downlink packet count to align with the server, ensuring continued communication.

AT Command

There is no downlink payload for this configuration.

3.4.2.24 When the limit bytes are exceeded, upload in batches

This command controls the behavior of the node when the combined size of the MAC commands (MACANS) from the server and the payload exceeds the allowed byte limit for the current data rate (DR). The command provides two modes: one enables splitting the data into batches to ensure compliance with the byte limit, while the other prioritizes the payload and ignores the MACANS in cases of overflow.

AT Command

Downlink Payload

3.4.2.25 Copy downlink to uplink

This command enables the device to immediately uplink the payload of a received downlink packet back to the server. The command allows for quick data replication from downlink to uplink, with a fixed port number of 100.

AT Command:

AT+RPL=5     // After receiving a downlink payload from the server, the device will immediately uplink the payload back to the server using port number 100.

Example：aa xx xx xx xx         // aa indicates whether the configuration has changed: 00 means YES, and 01 means NO. xx xx xx xx are the bytes uplinked back.

For example, sending 11 22 33 44 55 66 77 will return invalid configuration 00 11 22 33 44 55 66 77.

For example, if 01 00 02 58 is issued, a valid configuration of 01 01 00 02 58 will be returned.

Downlink Payload:

There is no downlink option available for this feature.

3.4.2.26 Query firmware version, frequency band, sub band, and TDC time

This command is used to query key information about the device, including its firmware version, frequency band, sub band, and TDC time. By sending the specified payload as a downlink, the server can retrieve this essential data from the device.

• Downlink Payload:

  26 01     //  The downlink payload 26 01 is used to query the device's firmware version, frequency band, sub band, and TDC time.

   

Example：

3.5 Integrating with ThingsEye.io

The Things Stack application supports integration with ThingsEye.io. Once integrated, ThingsEye.io acts as an MQTT client for The Things Stack MQTT broker, allowing it to subscribe to upstream traffic and publish downlink traffic.

3.5.1 Configuring The Things Stack

We use The Things Stack Sandbox in this example:

• In The Things Stack Sandbox, go to the Application for the LT-22222-L you added.
• Select MQTT under Integrations in the left menu.
• In the Connection information section, under Connection credentials, The Things Stack displays an auto-generated username. You can use it or provide a new one.
• Click the Generate new API key button to generate a password. You can view it by clicking on the visibility toggle/eye icon. The API key works as the password.

3.5.2 Configuring ThingsEye.io

The ThingsEye.io IoT platform is not open for self-registration at the moment. If you are interested in testing the platform, please send your project information to admin@thingseye.io, and we will create an account for you.

• Login to your ThingsEye.io account.
• Under the Integrations center, click Integrations.
• Click the Add integration button (the button with the + symbol).

On the Add integration window, configure the following:

Basic settings:

• Select The Things Stack Community from the Integration type list.
• Enter a suitable name for your integration in the Name text box or keep the default name.
• Ensure the following options are turned on.
  • Enable integration
  • Debug mode
  • Allow create devices or assets
• Click the Next button. you will be navigated to the Uplink data converter tab.

Uplink data converter:

• Click the Create new button if it is not selected by default.
• Enter a suitable name for the uplink data converter in the Name text box or keep the default name.
• Click the JavaScript button.
• Paste the uplink decoder function into the text area (first, delete the default code). The demo uplink decoder function can be found here.
• Click the Next button. You will be navigated to the Downlink data converter tab.

Downlink data converter (this is an optional step):

• Click the Create new button if it is not selected by default.
• Enter a suitable name for the downlink data converter in the Name text box or keep the default name.
• Click the JavaScript button.
• Paste the downlink decoder function into the text area (first, delete the default code). The demo downlink decoder function can be found here.
• Click the Next button. You will be navigated to the Connection tab.

Connection:

• Choose Region from the Host type.
• Enter the cluster of your The Things Stack in the Region textbox. You can find the cluster in the url (e.g., https://eu1.cloud.thethings.network/...).
• Enter the Username and Password of the MQTT integration in the Credentials section. The username and password can be found on the MQTT integration page of your The Things Stack account (see 3.5.1 Configuring The Things Stack).
• Click the Check connection button to test the connection. If the connection is successful, you will see the message saying Connected.

• Click the Add button.

Your integration has been added to the Integrations list and will be displayed on the Integrations page. Check whether the status is shown as Active. If not, review your configuration settings and correct any errors.

3.5.2.1 Viewing integration details

Click on your integration from the list. The Integration details window will appear with the Details tab selected. The Details tab shows all the settings you have provided for this integration.

If you want to edit the settings you have provided, click on the Toggle edit mode button. Once you have done click on the Apply changes button.

3.5.2.2 Viewing events

The Events tab displays all the uplink messages from the LT-22222-L.

• Select Debug from the Event type dropdown.
• Select the time frame from the time window.

• To view the JSON payload of a message, click on the three dots (...) in the Message column of the desired message.

3.5.2.3 Deleting an integration

If you want to delete an integration, click the Delete integration button on the Integrations page.

3.5.2.4 Viewing sensor data on a dashboard

You can create a dashboard with ThingsEye to visualize the sensor data coming from the LHT65N-VIB. The following image shows a dashboard created for the LT-22222-L. See Creating a dashboard in ThingsEye documentation for more information.

3.6 Interface Details

3.6.1 Digital Input Ports: DI1/DI2/DI3 (For LT-33222-L, Low Active)

Supports NPN-type sensors.

3.6.2 Digital Input Ports: DI1/DI2

• Connect the sensor's output to DI1-

• Connect the sensor's VCC to DI1+.

• Connect the sensor's output to DI1+

• Connect the sensor's GND DI1-.

• Connect the sensor's output to DI1+ with a 50K resistor in series.

• Connect the sensor's GND DI1-.

Example 4: Connecting to a Dry Contact sensor

From the DI port circuit above, activating the photocoupler requires a voltage difference between the DI+ and DI- ports. However, the Dry Contact sensor is a passive component and cannot provide this voltage difference on its own.

To detect a Dry Contact, you can supply a power source to one of the pins of the Dry Contact. A reference circuit diagram is shown below.

Example 5: Connecting to an Open Collector

3.6.3 Digital Output Ports: DO1/DO2

NPN output: GND or Float. The maximum voltage that can be applied to the output pin is 36V.

Note: The DO pins will float when the device is powered off.

3.6.4 Analog Input Interfaces

The analog input interface is shown below. The LT-22222-L will measure the IN2 voltage to calculate the current passing through the load. The formula is:

AC2 = (IN2 voltage )/12

Example:  Connecting a 4~20mA sensor

We will use the wind speed sensor as an example for reference only.

Specifications of the wind speed sensor:

Red:      12~24V

Yellow:  4~20mA

Black:   GND

Connection diagram:

Example: Connecting to a regulated power supply to measure voltage

Specifications of the regulated power supply:

Red:      12~24v

Black:   GND

3.6.5 Relay Output

3.7 LED Indicators

The table below lists the behavior of LED indicators for each port function.

4. Using AT Commands

The LT-22222-L supports programming using AT Commands.

4.1 Connecting the LT-22222-L to a PC

4.2 Common AT Command Sequence

4.2.1 Multi-channel ABP mode (Use with SX1301/LG308)

4.2.2 Single-channel ABP mode (Use with LG01/LG02)

4.2.3 Change to Class A

5. Case Study

5.1 Counting how many objects pass through the flow line

See How to set up to setup counting for objects passing through the flow line?

6. FAQ

This section contains some frequently asked questions, which can help you resolve common issues and find solutions quickly.

6.1 How to update the firmware?

Dragino frequently releases firmware updates for the LT-22222-L. Updating your LT-22222-L with the latest firmware version helps to:

• Support new features
• Fix bugs
• Change LoRaWAN frequency bands

You will need the following things before proceeding:

• 3.5mm programming cable (included with the LT-22222-L as an additional accessory)
• USB to TTL adapter/converter
• Download and install the STM32 Flash loader. (replaced by STM32CubeProgrammer)
• Download the latest firmware image from LT-22222-L firmware image files. Check the file name of the firmware to find the correct region.

Below is the hardware setup for uploading a firmware image to the LT-22222-L:

Start the STM32 Flash Loader and choose the correct COM port to update.

Note: If you have lost the programming cable, you can make one from a 3.5 mm cable. The pin mapping is as follows:

6.4 How to change the uplink interval?

Please see this link: http://wiki.dragino.com/xwiki/bin/view/Main/How%20to%20set%20the%20transmit%20time%20interval/ 

6.5 Can I see the counting event in the serial output?

7.4 Why can the LT-22222-L perform uplink normally, but cannot receive downlink?

The FCD count of the gateway is inconsistent with the FCD count of the node, causing the downlink to remain in the queue.
Use this command to synchronize their counts: Resets the downlink packet count

8. Ordering information

LT-22222-L-XXX:

XXX:

• EU433: LT with frequency bands EU433
• EU868: LT with frequency bands EU868
• KR920: LT with frequency bands KR920
• CN470: LT with frequency bands CN470
• AS923: LT with frequency bands AS923
• AU915: LT with frequency bands AU915
• US915: LT with frequency bands US915
• IN865: LT with frequency bands IN865
• CN779: LT with frequency bands CN779

9. Package information

Package includes:

• 1 x LT-22222-L I/O Controller
• 1 x LoRa antenna matched to the frequency of the LT-22222-L
• 1 x bracket for DIN rail mounting
• 1 x 3.5 mm programming cable

Dimension and weight:

• Device Size: 13.5 x 7 x 3 cm
• Device Weight: 105 g
• Package Size / pcs : 14.5 x 8 x 5 cm
• Weight / pcs : 170 g

10. Support

• Support is available Monday to Friday, from 09:00 to 18:00 GMT+8. Due to different time zones, we cannot offer live support. However, your questions will be answered as soon as possible within the aforementioned schedule.

• Please provide as much information as possible regarding your inquiry (e.g., product models, a detailed description of the problem, steps to replicate it, etc.) and send an email to support@dragino.cc

   

11. Reference​​​​​

• LT-22222-L: http://www.dragino.com/products/lora-lorawan-end-node/item/156-lt-22222-l.html
• Datasheet, Document Base
• Hardware Source