RS485 atmospheric pressure sensor

    SM2182B using the standard RS485 bus MODBUS-RTU protocol,easy access to PLC,DCS and other instruments or systems for monitoring atmospheric pressure 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

Technical parameterParameter value
BrandSONBEST
Atmospheric pressure range30~110kpa
Atmospheric pressure accuracy±0.5%
Communication InterfaceRS485
Default baud rate9600 8 n 1
PowerDC9~24V 1A
Running temperature-30~80°C
Working humidity5%RH~90%RH

Wiring instructions

    Any incorrect wiring can cause irreversible damage to the product. Please carefully wire the cable as follows in the case of power failure, and then connect the cable to confirm the correctness and then use it again. Some products have no lead, the core color is for reference only.
IDCore colorIdentificationNote
1RedV+Power +
2GreenV-Power -
3YellowA+RS485 A+
4BlueB-RS485 B-

Why choose this product?

SM2182B

SM2182B

SM2182B

SM2182B

SM2182B

SM2182B

SM2182B

SM2182B

SM2182B

SM2182B

Product Size

SM2182B

Communication Protocol

    The product uses RS485 MODBUS-RTU standard protocol format, all operation or reply commands are hexadecimal data. The default device address is 1 when the device is shipped, the default baud rate is 9600, 8, n, 1
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 01 84 0A .
Device IDFunction idStart AddressData LengthCRC16
010300 0000 0184 0A
    For the correct query frame, the device will respond with data:01 03 02 00 79 79 A6 , the response format is parsed as follows:
Device IDFunction idData Lengthdata 1Check Code
0103 0200 79 79 A6
    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.
2. Data Address Table
AddressStart AddressDescriptionData typeValue range
4000100 01atmospheric pressureread0~65535
4010000 64model coderead/write0~65535
4010100 65total pointsread/write1~20
4010200 66Device IDread/write1~249
4010300 67baud rateread/write0~6
4010400 68moderead/write1~4
4010500 69protocolread/write1~10
3 read and modify device address
(1) 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.
Device IDFunction idStart AddressData LengthCRC16
FA0300 6400 0290 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 IDFunction idStart Address Model CodeCRC16
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.
(2)Change device address
    For example, if the current device address is 1, we want to change to 02, the command is:01 06 00 66 00 02 E8 14 .
Device IDFunction idStart Address DestinationCRC16
010600 6600 02E8 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 IDFunction idStart AddressDestinationCRC16
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
(1) Read 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 IDFunction idStart AddressData LengthCRC16
01 0300 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 IDFunction idData Length Rate IDCRC16
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.
(2)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 IDFunction idStart Address Target Baud RateCRC16
010300 6600 0164 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.
4 Read Correction Value
(1) 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.
Device IDFunction idStart AddressData LengthCRC16
010300 6B00 01F5 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 IDFunction idData LengthData valueCRC16
01 0302 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. If the device has multiple parameters, other parameters operate in this way. The same, the general temperature, humidity have this parameter, the light generally does not have this item.
(2)Change correction value
    For example, 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 .
Device IDFunction idStart AddressDestinationCRC16
010600 6B00 64F9 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.

Product Pictures

SM2182B

Product Pictures

SM2182B

SM2182B

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