[英]How do I implement a stop button with Tkinter for a stepper motor system?
我對Tkinter
中停止按鈕的使用有疑問。
對於實驗,我必須設置 X/Y 平台,該平台使用兩個步進電機工作。 arduino 程序完美運行。 唯一的問題是,當我激活 start function 時,它將舞台驅動到各種坐標,它凍結了。 現在的問題是它必須連續運行數周,並且需要一個停止按鈕以應對緊急情況並通常停止步進電機。 停止按鈕必須做兩件事:它必須停止步進驅動電機,它必須中斷tkinter.after
循環。 但是,由於凍結,無法單擊按鈕。
這是我的代碼:
import tkinter as tk
import serial
ser = serial.Serial('COM5', 115200)
running = False
def quit():
"""Function that closes the serial port and destroys the root of the GUI"""
global root
ser.close()
root.destroy()
def route():
"""Writes coordinates to the arduino, which in return drives the stepper motors"""
if running == True:
# The g line stands for go to!
ser.write(b'g115000\r\n')
root.after(50)
ser.write(b'g225000\r\n')
root.after(30000)
ser.write(b'g1400\r\n')
root.after(50)
ser.write(b'g2500\r\n')
root.after(12000,route())
def zeroing():
"""Zeros the program, this is necessary for the stage to
calibrate it's boundary conditions"""
#zeros the stage so that it is ready to use!
varLabel.set("zeroing, please move away from the stage")
#the z command zeros the motors for boundary business
ser.write(b'z\r\n')
def run_program():
"""Runs the function Route and sets running to True (not a good start/stop system)"""
#starts the program, but only after you zero the stage
global running
running = True
varLabel.set("Program running")
route()
def stop_program():
"""Sets the running flag to False and sends a stop command to the arduino"""
#stops the program immediately
global running
running = False
varLabel.set("Program stopped,please zero before continuing")
#the s byte is a command that stops the stepper motors
ser.write(b's\r\n')
if __name__== "__main__":
root = tk.Tk()
canvas1 = tk.Canvas(root, width=800, height=400)
canvas1.pack()
root.title('XY-stage controller')
#instructions
instructions = tk.Label(root,text='Enter the amount of hours you want your measurements to last in the text box.'
'\n Click on run program to start a measurement session.'
'\n Click on stop incase of an emergency or if it is wanted to stop the program.',
font = "Raleway")
instructions.pack(side='bottom')
# initialize active labels
varLabel = tk.IntVar()
tkLabel = tk.Label(textvariable=varLabel,)
tkLabel.pack(side='top')
# Buttons for initializing a bunch of good functions
zerobutton = tk.IntVar()
tkrunprogram= tk.Button(
root,
text='Zero',
command = zeroing,
height = 4,
fg = "black",
width = 10,
bg = 'gray',
bd = 5,
activebackground = 'green'
)
tkrunprogram.pack(side='top')
runprogbutton = tk.IntVar()
tkrunprogram= tk.Button(
root,
text='Run Program',
command = run_program,
height = 4,
fg = "black",
width = 10,
bg = 'gray',
bd = 5,
activebackground = 'green'
)
tkrunprogram.pack(side='top')
stopbutton = tk.IntVar()
tkstopprog= tk.Button(
root,
text='Stop Program',
command = stop_program,
height = 4,
fg = "black",
width = 10,
bg = 'gray',
bd = 5,
activebackground = 'red'
)
tkstopprog.pack(side='top')
Buttonquit = tk.IntVar()
tkButtonQuit = tk.Button(
root,
text='Quit',
command = quit,
height = 4,
fg = "black",
width = 10,
bg = 'yellow',
bd = 5
)
# initialize an entry box
entry1 = tk.Entry(root)
durbox = canvas1.create_window(400, 200, window=entry1)
tkButtonQuit.pack(side='top')
root.mainloop()
最后的 after 命令將引入 60 分鍾的暫停,這將使程序凍結 60 分鍾。 希望有一個簡單的解決方案來中斷該功能!
先感謝您!
您可以使用多線程。 在單獨的線程中進行所有通信,並確保不在子線程中更新 GUI 組件。
這是一個最小的例子:
import serial
import tkinter as tk
from threading import Thread
import time
def start():
global running
stop()
btn.config(text="Stop", command=stop)
running = True
info_label["text"] = "Starting..."
thread = Thread(target=run, daemon=True)
thread.start()
def run():
ser = serial.Serial("COM5", 115200, timeout=2)
while running:
ser.write(b'g115000\r\n')
time.sleep(50)
ser.write(b'g225000\r\n')
time.sleep(30000)
ser.write(b'g1400\r\n')
time.sleep(50)
ser.write(b'g2500\r\n')
ser.write(b's\r\n')
ser.close()
def stop():
global running
running = False
info_label["text"] = "Stopped"
btn.config(text="Start", command=start)
root = tk.Tk()
running = False
info_label = tk.Label(root, text="INFO:")
info_label.pack()
btn = tk.Button(root, text="Start", command=start)
btn.pack()
root.mainloop()
after(x000)
實際上與time.sleep(x)
相同 - 它使整個應用程序進入睡眠狀態。 作為一般經驗法則,您永遠不應在與 GUI 相同的線程中執行此操作。 然而,這並不意味着您需要使用線程。
tkinter 的after
方法可讓您安排命令在未來運行。 如果您正在運行的命令速度很快,例如通過串行連接發送幾個字節,那么這就是您所需要的。 與使用線程相比,它更簡單並且開銷更少。
比如你的route
function大概可以這樣寫:
def route():
if running == True:
# immediately write this:
ser.write(b'g115000\r\n')
# after 50ms, write this:
root.after(50, ser.write, b'g225000')
# after 30 more seconds, write this
root.after(50+30000, ser.write, b'g1400\r\n')
# and then after 50ms more, write this
root.after(50+30000+50, ser.write, b'g2500\r\n')
# and finally, after 12 seconds, do it all again
root.after(50+30000+50+12000,route)
一旦你調用一次這個,你就不需要再次調用它,你也不需要在線程中調用它。 它只是將一些工作放在一個隊列中,在未來的某個時間被拾取。
由於每次調用root.after
返回一個 id,您可以保存這些 id,以便在想要停止一切的情況下,您可以對每個保存的 id 調用after_cancel
。
另一種方法是將作業定義為一系列延遲,然后是要寫入的字節。 例如:
job = (
(0, b'g115000\r\n'),
(50, b'g225000'),
(30000, b'g1400\r\n'),
(50, b'g2500\r\n'),
)
然后,您的route
function 可能看起來像這樣(未經測試,但這非常接近)
def route(job):
global after_id
delay = 0
for (delta, data) in job:
delay += delta
root.after(delay, ser.write, data)
delay += 12000
root.after(delay, route, job)
該主題有很多變體。 例如,您可以創建一個實現此邏輯的Job
class,或者job
可以包含命令而不是數據。 關鍵是,您可以定義一個數據結構來定義要完成的工作,然后使用after
來安排該工作。
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