SPECIFICATION
product name： | Atmospheric pressure transmitter |
Model： | BPS-1S |
version： | V1.0 |
Creator： | He Genwen |
reviewed by： | Yuan Chao |
Modify Record Table：
version | change content | Changed by | change date |
V1.0 | new-built | He Genwen | April 24, 2020 |
1、 Product Introduction
BPS-1S is a high-precision atmospheric pressure data acquisition transmitter that uses the MODBUS industrial control bus protocol. Multiple transmitters can be connected to a common bus network or other bus networks that comply with the MODBUS RTU protocol. This product can monitor changes in atmospheric pressure in real time and stably. It has the characteristics of small size, easy installation, reliable performance, long service life, and fast response speed.
2、 Applicable scope
Widely applicable in environments that require measuring air pressure, such as environmental monitoring, industrial monitoring, meteorological research, farmland measurement, and wind resource assessment.
3、 Technical parameters
Working power supply | DC 9V |
output signal | MODBUS RTU agreement |
Range range | 300hpa-1100hpa |
accuracy class | 0.5%FS |
response time | ≤1S (@25℃) |
operation temperature | 40℃~80℃ |
storage temperature |
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Installation method | Wall mounted+magnetic suction |
Shell parameters | ABS white 61X (45+18) X30mm |
weight | 34g |
4、4 Appearance dimension diagram (unit: mm, dimension tolerance: ± 1.0mm)
5、 Wiring diagram
Power supply positive pole (VCC)
RS485 output (A)
RS485 output (B)
Power negative terminal (GND)
6、 Communication protocol
1. Product command sending and response speed：
1)The recommended interval for sending instructions is greater than 0.5 seconds
2) It is recommended to read the response time after sending instructions, which should be greater than 0.2 seconds
2.Protocol Overview:
This agreement complies with the MODBUS communication protocol and adopts the subset RTU mode in the MODBUS protocol: RS485 half duplex working mode.
3. The commands and meanings of commands and data supported by integer values：
4. Serial data format:
1) CRC check polynomial:0xA001
2) The communication protocol can transmit signed integers or floating-point data
3) Serial port settings: The default baud rate is 9600bps, with 8 data bits, 1 stop bit, and no checksum bit
4)The serial baud rate supported by this transmitter
by:1200,2400,4800,9600,19200,38400,57600,115200
7、Detailed explanation of communication commands：
Read pressure value (integer) ：
Upper computer sends instructions：01 04 00 00 00 01 31 CA
The upper computer receives instructions：01 04 02 02 93 F8 3D
Among them: No 4、5 Bytes represent the current pressure value received，Divide its value by 100 to obtain the current actual pressure value；
In the above example 02 93，Decimal is 659，After dividing by 100, it is 6.59, which is the current pressure value。
Read pressure value command (floating-point number) ：
For the transmission of floating-point numbers, please refer to the regulations on multi byte floating-point number transmission in the MODBUS-RTU protocol。 dispatch orders Tx:01 03 00 16 00 02 25 CF
01 Slave address, 03 function code, 00 16 offset address, 00 02 word count 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 is a floating-point number for IEE754。
Pay attention to distinguishing the data base in the protocol, such as offset address 22 (10 base), represented by 16 in hexadecimal, and distinguish this difference。
Read communication baud rate：
dispatch ordersTx:01 03 00 01 00 01 D5 CA
Return dataRx:01 03 02 00 03 F8 45
Among them, the 4th and 5th bytes represent the high and low bits of the read communication baud rate：00 00
Example of rewriting baud rate command：
dispatch orders Tx: 01 06 00 01 00 04 D9 C9
01 Local address,06 function code,00 01 Offset Address,00 04 Rewrite the baud rate to 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, ignore the remaining data。
Example of Rewrite Address Command： (Note: After changing the address, execute the next save command)
dispatch orders 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：
dispatch orders Tx:02 06 FF FF 00 00 89 DD
02 Local address, 06 function code, FF FF offset address, 00 00 00 rewrite address 2 to cache. Return data Rx:02 06 FF FF 00 00 89 DD
8、note
The voltage used in the product cannot exceed the rated voltage range (9V-16V);
The installation height is the height of the human body or the equipment that mainly requires environmental conditions;
Install in a stable environment, avoid direct sunlight, stay away from windows, air conditioning, heating and other equipment, otherwise it may cause
Inaccurate atmospheric pressure measurement;
The probe part of the transmitter is a sensitive component. Please do not rotate or disassemble the casing casually. Improper operation may cause measurement errors
Inaccurate measurement may even damage sensitive components.
