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

For example: if the Unix Timestamp we got is hex 0x60137afd, we can convert it to Decimal: 1611889405. and then convert to the time: 2021 – Jan -- 29 Friday 03:03:25 (GMT)

Timestamp start and Timestamp end use Unix TimeStamp format as mentioned above. Devices will reply with all data log during this time period, use the uplink interval.

For example, downlink command   

Is to check 2020/12/1 07:40:00 to 2020/12/1 08:40:00's data

Uplink Internal =5s，means LHT52 will send one packet every 5s. range 5~255s.

AT Commands for Alarm mode:

AT+WMOD=1:                Enable/Disable Alarm Mode. (0:Disable, 1: Enable),need to reset the node to take effect

AT+CITEMP=1:               The interval to check temperature for Alarm. (Unit: minute)

AT+ARTEMP=-40,125:    Set the normal temperature range from -40°C to 125°C

Suppose you want to set the normal temperature from 15°C to 50°C, and turn on the alarm mode, and check the temperature every 2 minutes. Please refer to the following

Modification via downlink,Take TTN_V3 as an example(downlink commands, please refer to the downlink command set for details)

In order to ensure that the node is indeed modified by downlink, I reset the node to factory settings first.

Or use a downlink directly: AA010002000F0032 (See command info)

Use can configure LHT52 via AT Command or LoRaWAN Downlink.

There are two kinds of commands to configure LHT52, they are:

* General Commands.

These commands are to configure:

They are the same for all Dragino Devices which supports DLWS-005 LoRaWAN Stack(Note**). These commands can be found on the wiki: End Device Downlink Command

* Commands special design for LHT52

These commands are only valid for LHT52, as below:

Downlink Command:

No downlink command for this feature.

 5.  Sensors and Accessories

5.1  Temperature Probe (AS-01)

External Temperature Probe base on DS18B20. (note: Default Package doesn’t include AS-01)

External Temperature Probe (AS-01): 

• Resolution: 0.0625 °C
• ±0.5°C accuracy from -10°C to +85°C
• ±2°C accuracy from -55°C to +125°C
• Operating Range: -55 °C ~ 125 °C
• Cable Length: 2 meters

5.2  Program Converter (AS-02)

AS-02 is an optional accessory, it is USB Type-C converter. AS-02 provide below feature:

1. Access AT console of LHT52 when used with USB-TTL adapter. See this link.
2. Update firmware to LHT52 when used with DAP-Link adapter. See this link.

6. FAQ

6.1 How to use AT Command?

Connection:

✓ USB to TTL GND <-->GND

✓  USB to TTL RXD <--> D+

✓  USB to TTL TXD <--> A11

✓  USB to TTL 3.3V <--> D-

AT Command List is as below:

AT+<CMD>? :                  Help on <CMD>

AT+<CMD> :                   Run <CMD>

AT+<CMD>=<value> :   Set the value

AT+<CMD>=? :               Get the value

AT+DEBUG:    Set more info output

ATZ:                Trig a reset of the MCU

AT+FDR:         Reset Parameters to Factory Default, Keys Reserve

AT+DEUI:       Get or Set the Device EUI

AT+DADDR:   Get or Set the Device Address

AT+APPKEY:   Get or Set the Application Key

AT+NWKSKEY:   Get or Set the Network Session Key

AT+APPSKEY:     Get or Set the Application Session Key

AT+APPEUI:       Get or Set the Application EUI

AT+ADR:       Get or Set the Adaptive Data Rate setting. (0: off, 1: on)

AT+TXP:        Get or Set the Transmit Power (0-5, MAX:0, MIN:5, according to LoRaWAN Spec)

AT+DR:         Get or Set the Data Rate. (0-7 corresponding to DR_X)

AT+DCS:       Get or Set the ETSI Duty Cycle setting - 0=disable, 1=enable - Only for testing

AT+PNM:      Get or Set the public network mode. (0: off, 1: on)

AT+RX2FQ:    Get or Set the Rx2 window frequency

AT+RX2DR:    Get or Set the Rx2 window data rate (0-7 corresponding to DR_X)

AT+RX1DL:    Get or Set the delay between the end of the Tx and the Rx Window 1 in ms

AT+RX2DL:    Get or Set the delay between the end of the Tx and the Rx Window 2 in ms

AT+JN1DL:     Get or Set the Join Accept Delay between the end of the Tx and the Join Rx Window 1 in ms

AT+JN2DL:     Get or Set the Join Accept Delay between the end of the Tx and the Join Rx Window 2 in ms

AT+NJM:        Get or Set the Network Join Mode. (0: ABP, 1: OTAA)

AT+NWKID:    Get or Set the Network ID

AT+FCU:        Get or Set the Frame Counter Uplink

AT+FCD:        Get or Set the Frame Counter Downlink

AT+CLASS:    Get or Set the Device Class

AT+JOIN:       Join network

AT+NJS:        Get the join status

AT+SENDB:   Send hexadecimal data along with the application port

AT+SEND:     Send text data along with the application port

AT+RECVB:    Print last received data in binary format (with hexadecimal values)

AT+RECV:      Print last received data in raw format

AT+VER:        Get current image version and Frequency Band

AT+CFM:       Get or Set the confirmation mode (0-1)

AT+CFS:        Get confirmation status of the last AT+SEND (0-1)

AT+SNR:       Get the SNR of the last received packet

AT+RSSI:       Get the RSSI of the last received packet

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

AT+PORT:     Get or set the application port

AT+DISAT:    Disable AT commands

AT+PWORD:    Set password, max 9 digits

AT+CHS:       Get or Set Frequency (Unit: Hz) for Single Channel Mode

AT+CHE:       Get or Set eight channels mode,Only for US915,AU915,CN470

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+SLEEP:     Set sleep mode

AT+EXT:        Get or Set external sensor model

AT+BAT:        Get the current battery voltage in mV

AT+CFG:        Print all configurations

AT+WMOD:   Get or Set Work Mode

AT+ARTEMP:  Get or set the internal Temperature sensor alarm range

AT+CITEMP:   Get or set the internal Temperature sensor collection interval in min

AT+SETCNT:   Set the count at present

AT+RJTDC:     Get or set the ReJoin data transmission interval in min

AT+RPL:         Get or set response level

AT+TIMESTAMP:   Get or Set UNIX timestamp in second

AT+LEAPSEC:        Get or Set Leap Second

AT+SYNCMOD:    Get or Set time synchronization method

AT+SYNCTDC:      Get or set time synchronization interval in day

AT+PID:                Get or set the PID

6.2 Where to use AT commands and Downlink commands

AT commands：

Downlink commands:

TTN:

Helium：

Chirpstack:The downlink window will not be displayed until the network is accessed

Aws:

6.3 How to change the uplink interval？

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

6.4 How to use TTL-USB to connect a PC to input AT commands?

1    < - ->    GND  < - ->    Black

5    < - ->    RXD   < - ->    White

9    < - ->    TXD   < - ->    Green

To switch from download mode to command mode, press reset key

6.5 How to use TTL-USB to connect PC to upgrade firmware?

1    < - ->    GND  < - ->    Black

4    < - ->    3.3V   < - ->    Blue

5    < - ->    RXD   < - ->    White

9    < - ->    TXD   < - ->    Green

Press reset after connecting the 4boot cable to enter the download mode.

Step1: Install TremoProgrammer  first.

Step2：Download the LHT65N image files.

Step3：Select the serial port and baud rate of the device and the firmware to be upgraded.

Step4：Click Start 

Part Number:  LHT65N-XX-YY

XX : The default frequency band

YY: Sensor Accessories

Package Includes:

Dimension and weight:

This device complies with part 15 of the FCC Rules.Operation is subject to the following two conditions:

(1) This device may not cause harmful interference；

(2) this device must accept any interference received, including interference that may cause undesired operation.