keller PAA-3XX/80794系列（绝压）压力传感器

一、瑞士 keller（科勒）压力传感器

• keller英文版通讯协议百度网盘：提取码：fusc

1. 广播模式：所有从机都会收到上位机信息
   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.

2. 只有单一从机收到：
   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.

3. 如下数据格式：
   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、构建命令

• 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:

设备地址	方法代码	方法参数	CRC校验 高位	CRC校验 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 初始化设备-询问链接状态命令

每一个方法参数有 0-6 可选，类似modbus协议

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

设备地址	方法代码	方法参数	CRC校验 高位	CRC校验 低位
FA	30	04	43

1.2 查询浮点型压力、温度命令

Function：73 (16进制为：49)
F73: Read out current pressure and temperature values in floating-point format
命令：FA 49 01 A1 A7
（还有其他方法根据自己所需数据自己去协议找）

设备地址	方法代码	方法参数	CRC校验 高位	CRC校验 低位
FA	49	01	A1	A7

返回数据格式为：

设备地址	方法代码	方法参数	CRC校验 高位	CRC校验 低位
FA	49	01	A1	A7

1.3 方法总览

方法代码	16进制形式	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	读取最大值
F31	1f	Write scaling values
F32	20	Read out configurations	读取配置
F33	21	Write cinfigurations	写入配置
F48	30	Initialise devices, whereby the device ID is returned	初始化设备，返回设备ID，询问链接
F66	42	Programm bus address	总线地址
F69	45	Read out serial number
F73	49	Read out current pressure and temperature values in floating-point format	读取当前浮点型压力、温度数据
F74	4a	Read out current pressure and temperature values in integer format	读取当前压力温度整形数据
F95	5f	Zeroing functions	归零
F100	64	Read out configurations	读取配置
F101	65	Write configurations	写入配置

二、返回数据格式及解析

• 返回数据格式：
  

其中 B3、B2、B1、B0 一个八个十六进制字符，48 = 32 位，按照IEEE754规则表示的浮点数
其中第0位符号位S：1-9 一共8位（bytes）阶码E 9-32 一共23位表示尾数M 小数位 如：0.xxxxxx
整数位默认省略1，所以最后计算需要(-1)^S(1+M)*2^E-127

遵循IEEE754 浮点数定义：
IEEE754转化浮点数

• python 现成代码：楼主自己项目里面使用的

    def parsePressure(pressure):
        """
        压力数据格式为：FA 49 B3 B2 B1 B0 STAT CRC16_H CRC16_L
        FA 49 3F 81 61 ee 00 11 6f
        解析返回压力，统一返回千帕-kpa,保留7位小数
        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"]

串口模块

SeriaPort 类为继承serial 模块复写write/read 方法，（pip install pyserial）

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


class PressureSensor(object):
    """
    压力传感器型号为：keller  PAA-3XX/80794（绝压）
    协议类型： KELLER protoco （类MODBUS 协议）
    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):
        """
        压力数据格式为：FA 49 B3 B2 B1 B0 STAT CRC16_H CRC16_L
        FA 49 3F 81 61 ee 00 11 6f
        解析返回压力，统一返回千帕-kpa,保留7位小数
        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