Mar-16-2017, 02:10 PM
So I have been struggling for awhile now trying to display a variable value to a label. I have a loop setup to read an ADC value, translate that value back to a Pressure value ( I am reading a 4-20 mA signal from a dP sensor ) then print the current pressure value to label "CurrentLabel2" . No matter what I try it either does not work at all or just displays Pi_Var3 or something of the sort. I have imported my entire script below. I have almost no programming experience and am just working on this for fun to expand my knowledge. In short, I want the variable "x_Input" to display on "CurrentLabel2" and I am not sure how to do so. I have tried setting the "textvariable" command.
from Tkinter import*
import Tkinter as tk
from decimal import*
from time import*
from time import sleep
import RPi.GPIO as GPIO
import sys
import Adafruit_ADS1x15
import threading
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(7, GPIO.OUT)
GPIO.setup(11, GPIO.IN)
root=tk.Tk()
root.title("Test Room dP Controller")
root.geometry('800x480')
#uncomment the next line when ready to use with touchscreen.
#root.config(cursor='none')
# Establishing global variables. x is a translation from dP to Voltage
# in order to compare the Voltage input by the dP sensor to what the user wants.
# Entry_Output is just the value the slider is set to.
Entry_Output = tk.IntVar()
x = tk.IntVar()
ADC_Value = tk.IntVar()
x_Input = tk.IntVar()
adc = Adafruit_ADS1x15.ADS1115()
GAIN = 1
Spacer = tk.Label(root, height = 5).grid(row=1, column=1, columnspan =3)
# Setting the location for a slider scale.
DesiredEntry= tk.Scale(root, from_= -0.2, to = 0.2 , tickinterval=0.05, resolution=0.05, orient = 'horizontal',
font="Verdana 12", length=550, width=50)
DesiredEntry.grid(row=2,column=2)
DesiredEntryLabel = tk.Label(root, text = "Desired dP", font = "Verdana 18")
DesiredEntryLabel.grid(row = 2, column = 1)
UnitLabel= tk.Label(root, text= "inH2O", font="Verdana 12").grid(row=2,column=3)
# Establishing the variable "Entry_Output" as a modular level variable
# to pull the entry from the function 'PullData'.
def PullData(Entry_Output, x):
Entry_Output = DesiredEntry.get()
x = ((DesiredEntry.get()+0.25)/(1/2.4))
print(x)
def callback():
while True:
ADC_Value = adc.read_adc_difference(0,gain = GAIN)
print(ADC_Value, "ADC Value")
sleep(2)
x_Input = (((ADC_Value-68)*(1/8002.0))*(1/2.4))-0.25
print(x_Input, "Current Pressure")
t = threading.Thread(target = callback)
t.start()
Spacer2 = tk.Label(root, height = 2).grid(row=3,column=1,columnspan=3)
# Setting the location for a display.
CurrentLabel= tk.Label(root, text= "Current dP", font="Verdana 18").grid(row=4,column=1)
CurrentLabel2= tk.Label(root, font = "Verdana 20", width= 32, height= 1, relief= SUNKEN)
CurrentLabel2.grid(row=4,column=2)
UnitLabel2= tk.Label(root, text= "inH2O", font="Verdana 12").grid(row=4,column=3)
Spacer3 = tk.Label(root, height = 5).grid(row=5,column=1,columnspan=3)
# Setting the location for the button controls.
ButtonFrame= tk.Frame(root)
ButtonFrame.grid(row=6, column=1, columnspan=3)
B1 = tk.Button(ButtonFrame, text="Start", width=27, height= 3, font="Verdana 10 bold",
activebackground='green', command = lambda:PullData(Entry_Output, x)).grid(row=6, column=1)
B2 = tk.Button(ButtonFrame, text = "Shutdown", width=27, height=3, font="Verdana 10 bold",
activebackground = 'red').grid(row = 6, column = 2)
B3 = tk.Button(ButtonFrame, text="Close", width=27, height= 3, command=root.destroy,
font="Verdana 10 bold", activebackground='red').grid(row=6,column=3)
root.mainloop()