SONBUS KM75B71 RS485 Smoke Sensor

KM75B71 using the standard LORA Wireless Communication Interface, easy access to PLC, DCS, and other instruments or systems for monitoring soil moisture, and soil temperature state quantities. The internal use of high-precision sensing core and related devices to ensure high reliability and excellent long-term stability can be customized RS232, RS485, CAN,4 20mA, DC0~5V\10V, ZIGBEE, Lora, WIFI, GPRS and other output methods

Technical Parameters

Product Size

How to wiring?

Application solution

How to use it?

Communication Protocol

Because the device only has LORA wireless communication mode, the user can read and modify the parameters involved in this communication protocol through the wireless transparent transmission of the LORA transparent transmission module. The product uses the MODBUS-RTU standard protocol format, All operation or reply commands are hexadecimal data. The default device address is 1 when the device is shipped from the factory. The default baud rate is 9600, 8, n, 1. Since the LORA sensor cannot directly modify the LORA parameters, it is generally based on the standard parameters (434MHz). The carrier frequency, that is, channel 24) is shipped. If other parameters such as channel, signal bandwidth, and spreading factor are required, please specify when ordering.

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

For the correct query frame, the device will respond with data:01 03 04 00 79 00 7A AA 09 , the response format is parsed as follows:

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. Others and so on.

Data Address Table

Lora has a total of 32 channels. When the device is concentrated, you can change the channel to prevent signal crosstalk. The default channel value is 24, which corresponds to 434MHz. The device generates from 410MHz to 441MHz every 1MHz. For example, if the current channel value is 24, the actual frequency of use is 410+24=434MHz.
Device transmit power is divided into 4 files, 0 pairs are 20db, 1 pair is 17db, 2 pairs are 14db, and 3 pairs are 11db because the actual transmit power is related to many factors, so here is the maximum transmit power . Signal bandwidth is divided into 10 files,read-only, default 07, ie 125KHz, 0-9 are 7.8KHz, 10.4KHz, 15.6KHz, 20.8KHz, 31.2KHz, 41.7KHz, 62.5KHz, 125KHz, 250KHz ,500KHz.
the spreading factor value range is 0 to 6, read-only, the default is 02, ie SFactor=8, 0-6 corresponds to the spreading factor SFactor: 6, 7, 8, 9, 10, 11, 12, respectively.

read and modify device address

Read or query 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 Query device address.

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:

The 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’s main model is 21820, and the last two bytes 00 01 Indicates that the device has a status quantity.

Change devise address
For example, if the current device address is 1, we want to change it to 02, the command is: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:

The 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.

Read and Modify Baud Rate

Read baud rate
The device’s 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, and its format is parsed as follows.

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:

coded according to baud rate, 03 is 9600, ie the current device has a baud rate of 9600. Shanghai Sonbest Industrial Co., Ltd KLHA Brand Division

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 .

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.

Read Correction Value

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 difference can be modified to be plus or minus 1000, that is, the value range is 0-1000 or 64535 -65535. For example, when the display value is too small, we can correct it by adding 100. The command is: 01 03 00 6B 00 01 F5 D6 . In the command 100 is hex 0x64 If you need to reduce, you can set a negative value, such as -100, corresponding to the hexadecimal value of FF 9C, which is calculated as 100-65535=65435, and then converted to hexadecimal to 0x FF 9C. The correction value starts from 00 6B. We take the first parameter as an example. The correction value is read and modified in the same way for multiple parameters.

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 shown in the following table:

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. If the device has multiple parameters, other parameters operate in this way. The same, the general temperature, and humidity have this parameter, the light generally does not have this item.

Change correction value
For example, if the current state quantity is too small, we want to add 1 to its true value, and the current value plus 100 correction operation command is: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 a successful change.

Disclaimer

This document provides all information about the product, does not grant any license to intellectual property, does not express or imply, and prohibits any other means of granting any intellectual property rights, such as the statement of sales terms and conditions of this product, other issues. No liability is assumed. Furthermore, our company makes no warranties, express or implied, regarding the sale and use of this product, including the suitability for the specific use of the product, the marketability, or the infringement liability for any patent, copyright or other intellectual property rights, etc. Product specifications and product descriptions may be modified at any time without notice.

Contact Us

• Company: Shanghai Sonbest Industrial Co., Ltd KLHA Brand Division Address: Building 8, No.215 Northeast Road, Baoshan District, Shanghai, China Web: http://www.klha.com
• Web: http://www.klha.com
• SKYPE: soobuu
• Email: sale@sonbest.com
• Tel: 86-021-51083595 / 66862055 / 66862075 / 66861077

Documents / Resources

SONBUS KM75B71 RS485 Smoke Sensor [pdf] User Manual KM75B71 RS485 Smoke Sensor, KM75B71, RS485 Smoke Sensor

References

• User Manual