import serial
import time
import os
import sys
import win
from win import *
from PyQt5 import QtCore, QtGui, QtWidgets
class Okno (QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        QtWidgets.QWidget.__init__(self, parent)
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        self.ui.pushButton.clicked.connect (self.send)
    def send (self):
        dat1 = str(self.ui.lineEdit.text())
        print (dat1)
        ser = serial.Serial('COM2', 9600)
        data = (bytes(dat1, encoding='ascii'))
        ser.write (data)
        s=str(ser.readline())
        s=s[3:5]
        print (s)
        self.ui.label.setText ("%s" % s)
        temp = QtCore.pyqtSignal(int)
        self.temp.connect(self.ui.LcdNumber.display)
        self.temp.emit(s)
        
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
okoshko = Okno()
okoshko.show()
sys.exit(app.exec_())

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(551, 217)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(380, 20, 111, 61))
        self.pushButton.setObjectName("pushButton")
        self.lcdNumber = QtWidgets.QLCDNumber(self.centralwidget)
        self.lcdNumber.setGeometry(QtCore.QRect(40, 50, 161, 71))
        self.lcdNumber.setObjectName("lcdNumber")
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(280, 30, 71, 41))
        self.label.setObjectName("label")
        self.label_2 = QtWidgets.QLabel(self.centralwidget)
        self.label_2.setGeometry(QtCore.QRect(80, 10, 71, 21))
        self.label_2.setObjectName("label_2")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(380, 110, 113, 20))
        self.lineEdit.setObjectName("lineEdit")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 551, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)
    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "Отправить"))
        self.label.setText(_translate("MainWindow", "TextLabel"))
        self.label_2.setText(_translate("MainWindow", "Температура"))
if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())