一、瑞士 keller（科勒）壓力傳感器

keller英文版通訊協議百度網盤：提取碼：fusc

廣播模式：所有從機都會收到上位機信息
Broadcasting This mode of communication enables the master to transmit a message to all slaves
simultaneously. The master does not receive a reply, however, and is thus unable to check
whether the message has been correctly received by every slave.

只有單一從機收到：
Data interchange This mode of communication enables the master to communicate with a single slave. This
normally involves the transmission of two messages: the master transmits a request and
the slave responds to this request. Only the master is permitted to request a response. The
request is received by every slave, but only the selected slave responds. The response
must be received within a stipulated time, otherwise the master will assess the attempt as
failed and must transmit the request again.

如下數據格式：
The data are transmitted serially via the bus. The following format applies:
1 start bit
8 data bits (the least significant bit first)
1 stop bit
The parity bit can be set for devices of Class.Group = 5.20
9600 baud or 115’200 Baud (only with devices of Class.GrouThis results in 10 bits (11 bits with active parity bit) per transmission byte.

一、構建命令

命令字符串格式：

Note on the presentation of messages: Each box presents 1 data byte consisting of 8 bits, unless otherwise stated.
Each message sent by the master possesses the following format:

設備地址	方法代碼	方法參數	CRC校驗 高位	CRC校驗 低位
DevAddr	0 Function code	n byte parameters (optional)	CRC16_H	CRC16_L
FA	49	01	A1	A7

· DevAddr: Address of the device.
Address 0 is reserved for broadcasting.
Addresses 1...249 can be used for bus mode.
Address 250 is transparent and reserved for non-bus mode. Every device can be contacted with this address.
Addresses 251...255 are reserved for subsequent developments.
· Function code: Function number
A function is selected and executed by the device via the function number. The function number is encoded in 7 bits. Bit 7 is
always 0. The functions are described further below.
· Parameters:
The parameters required by the function (n = 0 .. 6, according to function)
· CRC16: 16-bit checksum
These two check bytes serve to verify the integrity of the received data. If an error is established, the entire message will be
discarded. The principle employed for CRC16 calculation is described in the appendix. The CRC16 standard is applied here.
Note: The length of a message from the master is at least 4 bytes.

1.1 初始化設備-詢問鏈接狀態命令

每一個方法參數有 0-6 可選，類似modbus協議

Function：48 (16進制為：30)
F48: Initialise devices, whereby the device ID is returned
命令：FA 30 04 43

設備地址	方法代碼	方法參數	CRC校驗 高位	CRC校驗 低位
FA	30	04	43

1.2 查詢浮點型壓力、溫度命令

Function：73 (16進制為：49)
F73: Read out current pressure and temperature values in floating-point format
命令：FA 49 01 A1 A7
（還有其他方法根據自己所需數據自己去協議找）

設備地址	方法代碼	方法參數	CRC校驗 高位	CRC校驗 低位
FA	49	01	A1	A7

返回數據格式為：

設備地址	方法代碼	方法參數	CRC校驗 高位	CRC校驗 低位
FA	49	01	A1	A7

1.3 方法總覽

方法代碼	16進制形式	功能描述(英文)	功能描述(中文)
F3		Read out the current pressure and temperature values in MODBUS format
F30	1e	Read out scaling values	讀取最大值
F31	1f	Write scaling values
F32	20	Read out configurations	讀取配置
F33	21	Write cinfigurations	寫入配置
F48	30	Initialise devices, whereby the device ID is returned	初始化設備，返回設備ID，詢問鏈接
F66	42	Programm bus address	總線地址
F69	45	Read out serial number
F73	49	Read out current pressure and temperature values in floating-point format	讀取當前浮點型壓力、溫度數據
F74	4a	Read out current pressure and temperature values in integer format	讀取當前壓力溫度整形數據
F95	5f	Zeroing functions	歸零
F100	64	Read out configurations	讀取配置
F101	65	Write configurations	寫入配置

二、返回數據格式及解析

返回數據格式：

其中 B3、B2、B1、B0 一個八個十六進制字符，48 = 32 位，按照IEEE754規則表示的浮點數
其中第0位符號位S：1-9 一共8位（bytes）階碼E 9-32 一共23位表示尾數M 小數位 如：0.xxxxxx
整數位默認省略1，所以最后計算需要(-1)^S(1+M)*2^E-127

遵循IEEE754 浮點數定義：
IEEE754轉化浮點數

python 現成代碼：樓主自己項目里面使用的

    def parsePressure(pressure):
        """
        壓力數據格式為：FA 49 B3 B2 B1 B0 STAT CRC16_H CRC16_L
        FA 49 3F 81 61 ee 00 11 6f
        解析返回壓力，統一返回千帕-kpa,保留7位小數
        0：KPA | 1： MPA | 3 PA | 5 bar
        :param pressure:
        :return:
        """
        UNIT = {
            "KPa": 1,
            "MPa": 1000,
            "Pa": 0.001,
            "Bar": 100
        }
        pressure16 = pressure[4:12]
        binAll = str(bin(int(pressure16, 16)))[2:]
        # binAll = binAll[2:]
        data = [x for x in binAll[:-24:-1]]
        data.reverse()
        binE = binAll[:-23]
        E = int(binE, 2) - 127
        total = 1
        for i, v in enumerate(data):
            total = total + int(v) * (2 ** -(i + 1))
        pressure = total*(2**E)
        return pressure*UNIT["Bar"]

串口模塊

SeriaPort 類為繼承serial 模塊復寫write/read 方法，（pip install pyserial）

from Lib.SerialPort import *
import time
import os
import threading
import binascii
import re


class PressureSensor(object):
    """
    壓力傳感器型號為：keller  PAA-3XX/80794（絕壓）
    協議類型： KELLER protoco （類MODBUS 協議）
    Each message sent by the master possesses the following format:
    DevAddr | 0 Function code | n byte parameters (optional) |CRC16_H CRC16_L
    """
    def __init__(self,com='COM14' ):
        self.seria = SerialPort(com,9600)
        self.last_str = "FA493F8161ee00116f"
        print('PressureSensor初始化成功')

    def readPressure(self):
        self.seria.Write(bytes.fromhex("FA 49 01 A1 A7"))
        pressurestr = str(binascii.b2a_hex(self.seria.Read()).decode())
        self.last_str = pressurestr if pressurestr != '' else self.last_str
        return self.parsePressure(self.last_str)

    def parsePressure(self, pressure):
        """
        壓力數據格式為：FA 49 B3 B2 B1 B0 STAT CRC16_H CRC16_L
        FA 49 3F 81 61 ee 00 11 6f
        解析返回壓力，統一返回千帕-kpa,保留7位小數
        0：KPA | 1： MPA | 3 PA | 5 bar
        :param pressure:
        :return:
        """
        UNIT = {
            "KPa": 1,
            "MPa": 1000,
            "Pa": 0.001,
            "Bar": 100
        }
        pressure16 = pressure[4:12]
        binAll = str(bin(int(pressure16, 16)))[2:]
        # binAll = binAll[2:]
        data = [x for x in binAll[:-24:-1]]
        data.reverse()
        binE = binAll[:-23]
        E = int(binE, 2) - 127
        total = 1
        for i, v in enumerate(data):
            total = total + int(v) * (2 ** -(i + 1))
        pressure = total*(2**E)
        return pressure*UNIT["Bar"]

三、更多

總結

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