Dragino LTC2 User manual

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LTC2 LoRaWAN Temperature Transmitter User Manual
Document Version: 1.1
Image Version: v1.0
Version
Description
Date
1.0
Release
2021-May-17
1.1
Correct Index
2021-Jul-5

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1. Introduction..............................................................................................................................4
1.1 What is LTC2 LoRaWAN Temperature Transmitter .....................................................................4
1.2 Features......................................................................................................................................4
1.3 Applications................................................................................................................................5
1.4 Hardware Change log.................................................................................................................5
1.5 Pin Definitions and Switch ..........................................................................................................5
1.5.1 Jumper JP2 ( Power ON) ...................................................................................................5
1.5.2 LED....................................................................................................................................5
1.5.3 PT100 Interfaces ...............................................................................................................6
1.5.4 Reset Button .....................................................................................................................6
1.6 Probe Variant..............................................................................................................................6
2. How to use LTC2?......................................................................................................................8
2.1 Connect to PT100 sensors ..........................................................................................................8
2.2 How it works?.............................................................................................................................8
2.3 Quick guide to connect to LoRaWAN server (OTAA) ...................................................................8
2.3.1 Step 1: Create a device in TTN with the OTAA keys from LTC2. ........................................8
2.3.2 Step 2: Power on LTC2 ....................................................................................................12
2.4 Uplink Payload..........................................................................................................................13
2.4.1 Payload Analyze..............................................................................................................13
2.5 Datalog Feature........................................................................................................................14
2.5.1 Unix TimeStamp..............................................................................................................14
2.5.2 Set Device Time ..............................................................................................................15
2.5.3 Poll sensor value .............................................................................................................16
2.5.4 Datalog Uplink payload...................................................................................................17
2.6 Alarm Mode..............................................................................................................................18
3. Configure LTC2 via AT Command or LoRaWAN Downlink ........................................................19
3.1 Set Transmit Interval Time........................................................................................................19
3.2 Enable PT100 channels.............................................................................................................19
3.3 Set External Sensor Mode.........................................................................................................20
3.4 Quit AT Command ....................................................................................................................21
3.5 Set system time ........................................................................................................................21
3.6 Set Time Sync Mode .................................................................................................................21

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3.7 Set Time Sync Interval ..............................................................................................................22
3.8 Retrieve data ............................................................................................................................22
3.9 Enable Alarm mode ..................................................................................................................22
3.10 Alarm check time.................................................................................................................22
3.11 Set Alarm Threshold ............................................................................................................23
3.12 Set Calibrate Value ..............................................................................................................23
3.13 Poll Calibrate Value..............................................................................................................24
3.14 Print data entries base on page...........................................................................................24
3.15 Print last few data entries....................................................................................................25
3.16 Clear Flash Record ...............................................................................................................25
4. Battery & How to replace........................................................................................................26
4.1 Battery Type .............................................................................................................................26
4.2 Replace Battery ........................................................................................................................26
4.3 Power Consumption Analyze ....................................................................................................26
5. Firmware Change Log and Upload Firmware...........................................................................27
6. FAQ.........................................................................................................................................28
6.1 How to use AT Command to configure LTC2 .............................................................................28
6.2 How to connect a customized PT100 cable? ............................................................................29
6.3 What is the frequency range of LTC2 LoRa part? .....................................................................31
6.4 How to change the LoRa Frequency Bands/Region? ................................................................31
7. Trouble Shooting.....................................................................................................................31
8. Order Info ...............................................................................................................................31
9. Packing Info ............................................................................................................................32
10. Support ..............................................................................................................................32

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1. Introduction
1.1 What is LTC2 LoRaWAN Temperature Transmitter
The Dragino LTC2 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 supports Datalog feature. User can retrieve the sensor value via LoRaWAN downlink
command.
LTC2 is powered by 8500mA Li-SOCI2 battery for long time measurement. The battery can run
2~10 years depends on the network environment and working mode.
Each LTC2 has two internal 24-bit ADC interfaces and are calibrated on 12 set resistors to make
sure the accuracy measurement on wide range.
LTC2 is LoRaWAN v1.0.3 compatible. Each LTC2 is pre-load with a set of unique keys for LoRaWAN
registration, 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
✓8500mAh Li-SOCI2 Battery
✓Firmware upgrade via console
✓Wall Mountable
✓Configurable via LoRa or UART

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✓Datalog and retrieve via LoRaWAN
✓Use pre-load PT100 probe or 3rd PT100 probe
✓Factory calibration for different resistance range
✓Support accuracy measure of resistance and upload
✓Battery Monitoring and upload
1.3 Applications
✓Logistics and Supply Chain Management
✓Food management
✓Cold chains solution
✓Industrial Monitoring and Control
1.4 Hardware Change log
LTC2 v1.0: Release.
1.5 Pin Definitions and Switch
1.5.1 Jumper JP2 ( Power ON)
Put a jumper on JP2 will power on the LTC2.
1.5.2 LED
The LED will flash in below case.
1) Send an uplink packet

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1.5.3 PT100 Interfaces
There are two independent channels to connect 2 x PT100 probes.
Each channel has 3-wire connection for 3-wire PT100 probes.
1.5.4 Reset Button
Press this button will reboot the LTC2
1.6 Probe Variant
LTC2 provide default probe version. See below for the variant:
Model
Photo
Description
LTC2-SI
Standard IP68 Probe Version
➢LTC2 with 1 x Standard IP68 PT100 probe.
➢Installation: Insert
➢Cable Length : 2m
➢PT100 Class : Class A
➢Probe Dimension: 4*30mm
➢Measure Range: -50 ~ 200 °C
➢Suitable Environment: General environment
LTC2-LT
Low Temperature Version
➢LTC2 with 1 x Low Temperature PT100 probe.
➢Installation: Insert
➢Cable Length : 2m
➢PT100 Class : Class A
➢Probe Dimension: 4*30mm
➢Measure Range: -196 ~ 150 °C
➢Suitable Environment: Low temperature
measurement, such as COVID vaccine transport
LTC2-FS
Food Safety Version
➢LTC2 with 1 x Food Safety PT100 probe.
➢Installation: Insert
➢Cable Length : 2m
➢PT100 Class : Class A
➢Probe Dimension: 4*150mm
➢Measure Range: -50 ~ 200 °C
➢Suitable Environment: Food temperature
measurement

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LTC2-FT
Flat Type Version
➢LTC2 with 1 x Flat Type PT100 probe.
➢Installation: Attached
➢Cable Length : 2m
➢PT100 Class : Class A
➢Probe Dimension: 8*25mm
➢Measure Range: -50 ~ 200 °C
➢Suitable Environment: Attached to the measure
point.
LTC2-HT
High Temperature Version
➢LTC2 with 1 x high temperature PT100 probe.
➢Installation: Insert
➢Cable Length : 3m
➢PT100 Class : Class A
➢Probe Dimension: 4*30mm
➢Measure Range: -70 ~ 550 °C
Suitable Environment: High Temperature
LTC2-NA
No Probe version:
➢User can connect to their own PT100 Probe
➢Grand Hole: M12
➢Suitable Environment:
Connect to customized probe

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2. How to use LTC2?
2.1 Connect to PT100 sensors
LTC2 has different probe option provided for ordering, if user has LTC2 with probe, just skip this
step. If user want to connect to a 3rd party PT100 probe, please see CONNECT A 3rd PARTY PT100
probe.
2.2 How it works?
The LTC2 is working in LoRaWAN OTAA Class A mode. Each LTC2 is shipped with a worldwide
unique set of OTAA and ABP keys. User needs to input the OTAA or ABP keys in the LoRaWAN
network server so to register. LTC2 will join the LoRaWAN network and start to transmit data. The
default period for each uplink is 20 minutes.
On each uplink, LTC2 will check its two ADC Interfaces and get the temperature from the sensor
and send out to server.
2.3 Quick guide to connect to LoRaWAN server (OTAA)
Here is an example for how to join the TTN v3 LoRaWAN Server. Below is the network structure,
in this demo we use DLOS8 as LoRaWAN gateway.
The DLOS8 is already set to connect to TTN . Rest we need to is register the LTC2 to TTN v3:
2.3.1 Step 1: Create a device in TTN with the OTAA keys from LTC2.

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Below is TTN screen shot:
➢Create Application first.
➢Manually Add a LoRaWAN End Device device. Choose OTAA and MAC v1.0.3
Input the OTAA keys for LTC2.

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Each LTC2 is shipped with a sticker with the default device EUI as below:
➢Input these keys to device portal.
➢Choose the Frequency band for this end node.

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➢Input APP Key in this page as well.
Add payload formatter So TTNv3 knows how to parse the LTC2 upload value.
The payload for TTN can be found at below link:
https://www.dragino.com/downloads/downloads/LoRa_End_Node/LTC2/Decoder/

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2.3.2 Step 2: Power on LTC2
LTC2 is power off when ship from factory.
Put a Jumper on JP2 to power on the device.
After power on, LTC2 will auto join to TTN network via the LoRaWAN coverage by DLOS8. After
join success, LTC2 will start to update message to IoT server.
Below is an example uplink message which shows the LTC2 is sending Join Request to TTNv3.

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After join successful, LTC2 will send uplink message with the sensor value.
Above value shows Channel1 detect 25.94 degree. There is no PT100 connected on Channel 2, so
it shows -327.67.
2.4 Uplink Payload
2.4.1 Payload Analyze
Below is the uplink payload which shows
✓BAT: Ex1: 0x0E3C ⇒ 3644 (mV) = 3.644 V
✓Status & EXT:
Bits
7
6
5
4
[3:0]
Status & Ext
Not Defined
Poll Message
Flag
Sync time
OK
Unix Time
Request
Ext:
0b(1001)
➢Poll Message Flag: 1: This message is a poll message reply, 0: means this is a normal uplink.
➢Sync time OK: 1: Set time ok，0: N/A. After time SYNC request is send, device will set this bit to 0
until got the time stamp from application server.
➢Unix Time Request:1: Request server downlink Unix time, 0 : N/A. In this mode, LTC2 will set this
bit to 1 every 10 day to request a time SYNC. (AT+SYNCMOD to set this)
➢EXT: The decode method for Channel 1 data and Channel 2 data
0b(0001): Upload PT100 temperature, with 2 decimals, range: -327.67 ~ 327.67 ℃
0b(0010): Upload PT100 temperature, with 1 decimals, range: -3276.7 ~ 3276.7 ℃
0b(0011): Upload Resistance instead of Temperature, range: -327.67 ~ 327.67 ohm
✓Channel1 data and Channel 2 data
Example Payload on
channel 1 or channel 2
Sensor Value when
EXT=0b(0001)
Sensor Value when
EXT=0b(0010)
Sensor Value when
EXT=0b(0011)
Size (bytes)
2
2
2
1
4
Value
BAT
Status & EXT
Channel 1 data
Channel 2 data
Unix TimeStamp

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0x1422
0x1422/100 = 51.54℃
0x1422/10 = 515.4℃
0x1422/100 = 51.54Ω
0xEC2D
(0xEC2D-65536)/100
= -50.75 ℃
(0xEC2D-65536)/10
= -507.5 ℃
(0xEC2D-65536)/100
= -50.75Ω
✓Unix TimeStamp
Refer to Datalog feature.
Example Uplink Payload:
Uplink payload example 1:0CE9011422EC2D6073E83B
➢Bat voltage:0x0CE9 =3305mV
➢Ext=0x01
➢Channel1 temp=0x1422/100=51.54 ℃
➢Channel2 temp=0xEC2D/100=-50.75 ℃
➢System timestamp=0x6073E83B= 1618208827(UTC)
Uplink payload example 2:0CED020203FE056073E697
➢Bat voltage:0x0CED =3309mV
➢Ext=0x02
➢Channel1 temp=0x0203/10=51.5 ℃
➢Channel2 temp=0xFE05/10=-50.7 ℃
➢System timestamp=0x6073E697=1618208407(UTC)
Uplink payload example 3 :0CE9032EDE1F406073E967
➢Bat voltage:0x0CE9 =3309mV
➢Ext=0x03
➢Channel1 res=0x2EDE/100=119.98 ohm
➢Channel2 res=0x1F40/100=80.00 ohm
➢System timestamp=0x6073E967= 1618209127(UTC)
2.5 Datalog Feature
LTC2 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.
LoRaWAN server must be v1.0.3 or higher, if LoRaWAN server doesn’t support this time request,
user can manually set the timestamp.
2.5.1 Unix TimeStamp
LTC2 uses Unix TimeStamp format base on

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User can get this time from link: https://www.epochconverter.com/ :
Below is the converter example
So, we can use AT+TIMESTAMP=1611889405 or downlink 3060137afd00 to set current time 2021
– Jan -- 29 Friday 03:03:25
2.5.2 Set Device Time
There are two ways to set device’s time:
1. Through LoRaWAN MAC Command (Default settings)
User need to set SYNCMOD=1 to enable sync time via MAC command.
Once LTC2 Joined LoRaWAN network, it will send the MAC command (DeviceTimeReq) and server
will reply with (DeviceTimeAns) to send the current time to LTC2. If LTC2 fails to get the time from
server, LTC2 will use the internal time and wait for next time request (AT+SYNCTDC to set time
request period, default is 10 days).
Note: LoRaWAN Server need to support LoRaWAN v1.0.3(MAC v1.0.3) or higher to support this
MAC command feature, Chirpstack,TTN v3 and loriot support but TTN v2 doesn’t support. If
server doesn’t support this command, it will through away uplink packet with this command, so
user will lose the packet with time request for TTN v2 if SYNCMOD=1.
2. Manually Set Time
User need to set SYNCMOD=0 to manual time, otherwise the user set time will be overwrite by
the time set by server.

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2.5.3 Poll sensor value
User can poll sensor value base on timestamps from server. Below is the downlink command.
1byte
4bytes
4bytes
1byte
31
Timestamp start
Timestamp end
Uplink Interval
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 31 60A06E90 60A07CA0 0A
Is to check 2021/5/16 01:00:00 to 2021/5/16 02:00:00’s data
Uplink Internal =10s，means LTC2 will send one packet every 10s. range 5~255s.

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2.5.4 Datalog Uplink payload
When server senser a datalog polling to LTC2, LTC2 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:
a) DR0: max is 11 bytes so one entry of data
b) DR1: max is 53 bytes so devices will upload 4 entries of data (total 44 bytes)
c) DR2: total payload includes 11 entries of data
d) 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 has below data inside Flash:
Flash Addr |Unix Time | Ext | BAT voltage| Value
8021630 systime= 2021/5/16 01:17:44 1 3684 Temp1=28.89 Temp2=-327.67
8021640 systime= 2021/5/16 01:37:44 1 3681 Temp1=28.79 Temp2=-327.67
8021650 systime= 2021/5/16 01:57:44 1 3681 Temp1=28.67 Temp2=-327.67
8021660 systime= 2021/5/16 02:17:44 1 3684 Temp1=28.60 Temp2=-327.67
8021670 systime= 2021/5/16 02:37:44 1 3684 Temp1=28.56 Temp2=-327.67
8021680 systime= 2021/5/16 02:57:44 1 3684 Temp1=28.52 Temp2=-327.67
8021690 systime= 2021/5/16 03:17:44 1 3684 Temp1=28.51 Temp2=-327.67
80216A0 systime= 2021/5/16 03:37:44 1 3684 Temp1=28.50 Temp2=-327.67
80216B0 systime= 2021/5/16 03:57:44 1 3684 Temp1=28.46 Temp2=-327.67
If user send below downlink command:
3160A06E9060A098C00A
Where : Start time: 60A06E90 = time 21/5/16 01:00:00
Stop time: 60A098C0 = time 21/5/16 04:00:00
LTC2 will uplink this payload.

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0E64410B49800160A072B80E61410B3F800160A077680E61410B33800160A07C180E64410B2C8
00160A080C80E64410B28800160A085780E64410B24800160A08A280E64410B23800160A08ED
80E64410B22800160A093880E64410B1E800160A09838
Where the first 11 bytes is for the first entry:
0E64410B49800160A072B8
Bat voltage:0x0E64 =3684mV
poll message flag & Ext=0x41,means reply data,Ext=1
Channel1 temp=0x0B49/100=28.89℃
Channel2 temp=0x8001/100=-327.67℃
System timestamp=0x60A072B8= 1621127864(UTC)
2.6 Alarm Mode
LTC2 can monito the temperature in every CTTEMP time, when the temperature exceed the limit ,
it will uplink the sensor value immediately.
Detail commands see:
Enable Alarm Mode.
Config Alarm Sampling Time.
Set Alarm Threshold

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3. Configure LTC2 via AT Command or LoRaWAN Downlink
Use can configure LTC2 via AT Command or LoRaWAN Downlink.
➢AT Command Connection: See FAQ.
➢LoRaWAN Downlink instruction for different platforms:
http://wiki.dragino.com/index.php?title=Main_Page#Use_Note_for_Server
There are two kinds of commands to configure LTC2, they are:
➢General Commands.
These commands are to configure:
✓General system settings like: uplink interval.
✓LoRaWAN protocol & radio related command.
They are same for all Dragino Device which support DLWS-005 LoRaWAN Stack. These
commands can be found on the wiki:
http://wiki.dragino.com/index.php?title=End_Device_Downlink_Command
➢Commands special design for LTC2
These commands only valid for LTC2, as below:
3.1 Set Transmit Interval Time
Feature: Change LoRaWAN End Node Transmit Interval.
AT Command: AT+TDC
Command Example
Function
Response
AT+TDC=?
Show current transmit Interval
30000
OK
the interval is 30000ms = 30s
AT+TDC=60000
Set Transmit Interval
OK
Set transmit interval to 60000ms =
60 seconds
Downlink Command: 0x01
Format: Command Code (0x01) followed by 3 bytes time value.
If the downlink payload=0100003C, it means set the END Node’s Transmit Interval to
0x00003C=60(S), while type code is 01.
➢Example 1: Downlink Payload: 0100001E // Set Transmit Interval (TDC) = 30 seconds
➢Example 2: Downlink Payload: 0100003C // Set Transmit Interval (TDC) = 60 seconds
3.2 Enable PT100 channels

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Feature: Enable PT100 channels. Default only Enable Channel 1
AT Command: AT+ENPTCHNUM
Command Example
Function
Response
AT+ENPTCHNUM=?
Get current ENPTCHNUM settings
1
OK
AT+ ENPTCHNUM =1
Enable channel 1
AT+ ENPTCHNUM =2
Enable channel 1 and 2
Downlink Command: 0xA1
Total bytes: 2 bytes
Example:
0xA101: same as AT+ENPTCHNUM =1
0xA102: same as AT+ENPTCHNUM =2
3.3 Set External Sensor Mode
Feature: Change External Sensor Mode.
AT Command: AT+EXT
Command Example
Function
Response
AT+EXT=?
Get current EXT settings
1
OK
AT+EXT=1
Set EXT to 0b(0001)
AT+EXT=2
Set EXT to 0b(0010)
AT+EXT=3
Set EXT to 0b(0011)
Downlink Command: 0xA2
Total bytes: 2 bytes
Example:
0xA201: same as AT+EXT=1