Product Specifications
Product Name: | Atmospheric pressure transmitter |
Product model: | BPS-1S |
Version: | V1.0 |
Formulator: | He Genwen |
Reviewer: | Yuan Chao |
Modify the record table:
Version | Change content | Change people | Change date  |
V1.0 | New | He Genwen | 2020-4-24 |
1. Product Introduction
BPS-1S It is a high-precision atmospheric pressure data acquisition transmitter, using MODBUS Industrial control bus protocol, multiple transmitters can be connected to the network for common bus, or other compliant MODBUS RTU Protocol bus networking.This product can monitor changes in atmospheric pressure in real time and stably, and has the characteristics of small size and easy installation. The product has reliable performance, long service life and fast response speed.
2. Scope of application
Widely applicable to environments where air pressure is measured, such as environmental testing, industrial testing, meteorological research, farmland measurement, wind resource assessment, etc.
3. Technical parameters
Working power supply | DC 9V |
Output signal | MODBUS RTU protocol |
Range range | 300hpa-1100hpa |
Accuracy level | 0.5%FS |
Response time | ≤1S (@25℃) |
Operating temperature | 40℃~80℃ |
Storage temperature |
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Installation method | Wall hang +Magnetic suction |
Shell parameters | ABS White 61 X (45+18) X30mm |
weight | 34g |
4. Appearance and size drawing (unit: mm， Dimensional tolerance: ± 1.0mm)
V. Wiring diagram
Power supply positive pole (VCC)
RS485 Output (A)
RS485 Output (B)
Negative power supply (GND)
VI. Communication Protocol
1.Product command sending and response speed:
1) The instruction sending time interval is recommended to be greater than 0.5 seconds
2) The recommended time for reading response after sending the command is greater than 0.2 seconds
2.Agreement Overview:
Compliance with this Agreement MODBUS Communication protocol, adopted MODBUS Subsets in the protocol RTU Way: RS485 Half-duplex Working mode.
3.The meaning of commands and commands and data supported by skewers:
4.Serial data format:
1) CRC Verification polynomial: 0 xA001
2) Communication protocols can transmit signed shaping numbers or floating-point type data.
3) Serial port setting: the baud rate default is 9600 bps，8 Bit data bit, 1 bit stop bit, no check bit
4) The serial port baud rate supported by this transmitter
It is: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200
7. Detailed explanation of communication commands:
Read pressure value (Integer ) ：
The command sent by the host computer: 01 04 00 00 00 01 31 CA
The host computer received the command: 01 04 02 02 93 F8 3D
Among them: the 4th and 5th bytes represent the received current pressure value, and its value is divided by 100 that is the current actual pressure value;
In the above example, it is 02 93, and the decimal is 659. Divided by 100 and it is 6.59, which is the current pressure value. 
Read pressure value command (Floating point number ) ：
Please refer to the transmission of floating point numbers MODBUS-RTU Provisions on multi-byte floating point transmission in the protocol.Send command Tx:01 03 00 16 00 02 25 CF
01 Slave address, 03 Function code, 00 16 Offset address, 00 02 Number of words read.
Return data Rx:01 03 04 BE 40 E6 12 15 A2
01 Slave address, 03 function code, 04 bytes, BE 40 E6 12 for IEE754 floating point number.
Pay attention to distinguishing the data division in the protocol, such as offset address 22 (10 Pricing ) ，16 The binary is expressed as 16, pay attention to distinguishing this difference.
Read communication baud rate:
Send command Tx:01 03 00 01 00 01 D5 CA
Return data Rx:01 03 02 00 03 F8 45
Among them: the 4th and 5th bytes are the high and low bits of the read communication baud rate: 00 00
Examples of rewriting baud rate commands:
Send command Tx: 01 06 00 01 00 04 D9 C9
01 Local address, 06 function code, 00 01 offset address, 00 04 rewrite baud rate is 4 (Corresponding to 19200 ) to cache.
Return data Rx: 01 06 00 01 00 04 D9 C9
Query address command: Send command Tx: 00 03 00 16 00 02 24 1E
Return data Rx: 02 03 04 40 16 D1 24 61 7C
02 For the local address found, the remaining data is ignored.
Example of rewriting address command: (Note: After changing the address, you must execute the next save command )
Send command Tx:01 06 00 00 00 02 08 0B
01 Local address, 06 function code, 00 00 offset address, 00 02 Rewrite address 2 to cache.
Return data Rx:01 06 00 00 00 02 08 0B
Save address command:
Send command Tx:02 06 FF FF 00 00 89 DD
02 Local address, 06 function code, FF FF Offset address, 00 00 Rewrite address 2 to cache.Return data Rx:02 06 FF FF 00 00 89 DD
8. Things to note
The product's voltage cannot exceed the rated voltage range (9V-16V) ；
The installation height is the height of the equipment that mainly requires environmental conditions;
Install in a stable environment to avoid direct light and stay away from windows, air conditioners, heating and other equipment, otherwise it will cause
Inaccurate measurement of atmospheric pressure;
The transmitter probe part is a sensitive component, please do not rotate or remove the housing at will. Improper operation may cause measurement.
Inaccurate quantity or even damage sensitive components.
