3WIRE - IoT Sensors
THX2RS
RS485 Modbus RTU enabled temperature & humidity sensor
INTRODUCTION
THX2RS is the latest RS485 Modbus RTU enabled temperature & humidity sensor. It is easily integrated for use with PLC, DCS, SCADA and other instruments or systems for monitoring temperature and humidity.
Its measurement is based on high-precision sensing core to ensure high reliability and excellent longterm stability. The entire sensor is packaged in a robust stainless-steel shell and comes with the required mounting bracket.
| TECHNICAL PARAMETERS | |
|---|---|
| Temperature Measurement Range | -40~85°C |
| Temperature Measurement Accuracy | ±0.5°C @ 25°C |
| Humidity Measurement Range | 0% ~ 100%RH |
| Humidity Measurement Accuracy | +/- 1% RH |
| Communication Interface | RS485 – Modbus RTU |
| Default Baud Rate | # 1, 9600 8 n 1 |
| Power | DC 6V ~ 24V @ 1A |
| Operating Temperature | -40~80°C |
| Operating Humidity | 5%RH ~ 90%RH |
PRODUCT DETAILS
COMMUNICATION PROTOCAL
THX2RS uses RS485 MODBUS-RTU standard protocol format, all operation or reply commands are in hexadecimal data.
The default device address is 1 when the device is shipped, the default baud rate is 9600, 8, n, 1
DIMENSIONS
1. Read Data (Function id 0x03)
Inquiry frame (hexadecimal), sending example: Query 1# device 1 data, the host computer sends the command:01 03 00 00 00 02 C4 0B.
| Device ID | Function ID | Start Address | Data Length | CRC16 |
|---|---|---|---|---|
| 01 | 03 | 00 00 | 00 02 | C4 0B |
For the correct query frame, the device will respond with data:01 03 04 00 7A 00 00 DB EA, the response format is parsed as follows:
| Device ID | Function ID | Data Length | Data 1 | Data 2 | Check Code |
|---|---|---|---|---|---|
| 01 | 03 | 04 | 00 79 | 00 7A | DB EA |
Data Description: The data in the command is hexadecimal. Take data 1 as an example. 00 79 is converted to a decimal value of 121. If the data magnification is 100, the actual value is 121/100=1.21.
2. Data Address Table
| Address | Start Address | Description | Data Type | Value Range |
|---|---|---|---|---|
| 40001 | 00 00 | Temperature | 00 02 | 0~65535 |
| 40002 | 00 01 | Humidity | 00 02 | 0~65535 |
| 40101 | 00 64 | Model Code | 00 02 | 0~65535 |
| 40102 | 00 65 | Total Points | 00 02 | 1~20 |
| 40103 | 00 66 | Device ID | 00 02 | 1~249 |
| 40104 | 00 67 | Baud Rate | 00 02 | 0~6 |
| 40105 | 00 68 | Mode | 00 02 | 1~4 |
| 40106 | 00 69 | Protocal | 00 02 | 1~10 |
| 40108 | 00 6B | Correction Value Temperature | Read/write | +0 ~ +1000 or 64535 (-1000) ~ 65535 (-0). |
| 40109 | 00 6C | Correction Value Humidity | Read/write | +0 ~ +1000 or 64535 (-1000) ~ 65535 (-0) |
3. Read & Modify Device Address
If you don’t know the current device address and there is only one device on the bus, you can use the command FA 03 00 64 00 02 90 5F to query the device address.
| Device ID | Function ID | Start Address | Data Length | CRC16 |
|---|---|---|---|---|
| FA | 03 | 00 64 | 00 02 | 90 5F |
FA is 250 for the general address. When you don’t know the address, you can use 250 to get the real device address, 00 64 is the device model register.
For the correct query command, the device will respond, for example the response data is: 01 03 02 07 12 3A 79, the format of which is as shown in the following table:
| Device ID | Function ID | Start Address | Model Code | CRC16 |
|---|---|---|---|---|
| 01 | 03 | 02 | 55 3C 00 01 | 3A 79 |
Response should be in the data, the first byte 01 indicates that the real address of the current device is, 55 3C converted to decimal 20182 indicates that the current device main model is 21820, the last two bytes 00 01 Indicates that the device has a status quantity.
• Change device address
For example, if the current device address is 1, and you want to change to 02, the command is:01 06 00 66 00 02 E8 14
| Device ID | Function ID | Start Address | Destination | CRC16 |
|---|---|---|---|---|
| 01 | 06 | 00 66 | 00 02 | E8 14 |
After the change is successful, the device will return information: 02 06 00 66 00 02 E8 27, its format is parsed as shown in the following table:
| Device ID | Function ID | Start Address | Destination | CRC16 |
|---|---|---|---|---|
| 01 | 06 | 00 66 | 00 02 | E8 27 |
Response should be in the data, after the modification is successful, the first byte is the new device address. After the general device address is changed, it will take effect immediately. At this time, the user needs to change the query command of the software at the same time.
4. Read and Modify Baud Rate
The device default factory baud rate is 9600. If you need to change it, you can change it according to the following table and the corresponding communication protocol. For example, read the current device’s baud rate ID, the command is:01 03 00 67 00 01 35 D5, its format is parsed as follows.
| Device ID | Function ID | Start Address | Data Length | CRC16 |
|---|---|---|---|---|
| 01 | 03 | 00 67 | 00 01 | 35 D5 |
Read the baud rate encoding of the current device. Baud rate encoding: 1 is 2400; 2 is 4800; 3 is 9600;4 is 19200; 5 is 38400; 6 is 115200.
For the correct query command, the device will respond, for example the response data is: 01 03 02 00 03 F8 45, the format of which is as shown in the following table:
| Device ID | Function ID | Data Length | Rate ID | CRC16 |
|---|---|---|---|---|
| 01 | 03 | 02 | 00 03 | F8 45 |
coded according to baud rate, 03 is 9600, ie the current device has a baud rate of 9600.
• Change the baud rate
For example, changing the baud rate from 9600 to 38400, ie changing the code from 3 to 5, the command is: 01 06 00 67 00 05 F8 1601 03 00 66 00 01 64 15
| Device ID | Function ID | Start Address | Target Baud Rate | CRC16 |
|---|---|---|---|---|
| 01 | 03 | 00 66 | 00 01 | 64 15 |
Change the baud rate from 9600 to 38400, changing the code from 3 to 5. The new baud rate will take effect immediately, at which point the device will lose its response and the baud rate of the device should be queried accordingly. Modified.
5. Read Correction Value
When there is an error between the data and the reference standard, we can reduce the display error by adjusting the correction value. The correction value starts from register 00 6B. We take the first parameter as an example. The correction value is read and modified in the same way for multiple parameters.
| Device ID | Function ID | Start Address | Data Length | CRC16 |
|---|---|---|---|---|
| 01 | 03 | 00 6B | 00 01 | F5 D6 |
For the correct query command, the device will respond, for example the response data is: 01 03 02 00 64 B9 AF, the format of which is as shown in the following table:
| Device ID | Function ID | Data Length | Data Value | CRC16 |
|---|---|---|---|---|
| 01 | 03 | 02 | 00 64 | B9 AF |
In the response data, the first byte 01 indicates the real address of the current device, and 00 6B is the first state quantity correction value register.
6. Change correction value
The correction difference can be modified to be plus or minus 1000, that is, the value range is +0 ~ +1000 or 64535 (-1000) ~ 65535 (-0). For example, when the display value is too small, we can correct it by adding 100. The command is: 01 06 00 6B 00 64 F9 FD . In the command 100 is hex 0x 64 If you need to reduce, you can set a negative value, such as -100, corresponding to the hexadecimal value of FF 9B, which is calculated as 100 – 65535 = 65435 (FF 9B), and then converted to hexadecimal to 0x FF 9B. For example, the current state quantity is too small, we want to add 1 to its true value, and the current value plus 100 (100 = 1.00) correction operation command is:01 06 00 6B 00 64 F9 FD
| Device ID | Function ID | Start Address | Destination | CRC16 |
|---|---|---|---|---|
| 01 | 06 | 00 6B | 00 64 | F9 FD |
After the operation is successful, the device will return information: 01 06 00 6B 00 64 F9 FD, the parameters take effect immediately after successful change.