Experimental Physics and
Industrial Control System

[email protected] (Noboru Yamamoto) · Wed, 4 Jun 1997 21:18:03 +0900

Hi,

 Enclosed is a sample python program which displays windows on X-terminal.
Each window has a slider and a label which are both connected to EPICS channel.

 I also enclosed ca.py which implements EPICS channel class in python. ca.py
uses _ca module which are written in C. Python can retuns any value, includig
list called tuple in Python, as a return value of get().
Development status is quite preliminary but(or because of it) I appriciate
your comments.

Thank you,

Noboru Yamamoto
KEK, Accelerator Lab.
Noboru Yamamoto
KEKB Accelerator Control Group
KEK, JAPAN
Fax:+81-298-64-0321
Tel:+81-298-64-5309
e-mail:[email protected]
#
import ca
from Tkinter import *

class Simple(ca.channel,Frame):
	def __init__(self,name,master=None,*cnf):
		Frame.__init__(self,master)
		self.pack(expand=1,fill='both')
		ca.channel.__init__(self,name);self.pendio(0.1)
		self.get();self.pendio()
		l=Label(self,text="CA readback")
		l.pack()
		s=Scale(self,orient="horizontal",label=name)
		s.pack(expand=1,fill='x')
		s.set(self.val)
		b=Button(self,text="Quit",command=self.quit,text=`self.val`)
		b.pack()
		self.s=s
		self.b=b
		self.l=l
		self.monitor(self.update_scale)
		self.monitor(self.update_label)
		self.pendio()
		self.s.config(command=self.scale_change)

	def repeater(self): # in-efficient compared to alarm routin in C
		self.pendio(0.0005)
		self.after(20,self.repeater)		

	def scale_change(self,arg):
		v=self.s.get()
		if( v <> self.val):
			self.put(v)
			self.pend_event(0.0005)

	def update_label(self,val):
		self.val,self.stat=val
		self.l.config(text=`self.val`)

	def update_scale(self,val):
		self.val,self.stat=val
		self.s.set(self.val)

if(__name__ == "__main__"):
	Simple("FFTB:WS2",master=Tk())
	Simple("FFTB:WS3",master=Toplevel())
	Simple("FFTB:WS1",master=Toplevel()).mainloop()

import _ca

pendio=_ca.pendio #export pendio 
pend_event=_ca.pend_event
flush_io=_ca.flush

class channel:
	def __init__(self,name):
		self.chid=_ca.search(name)
		self.val=0.0
		self.evid=[]

	def __del__(self):
		self.clear_monitor()
		_ca.clear(self.chid)
		_ca.pendio(1.0)	

	def get(self):
		_ca.get(self.chid, self.update_val)

	def put(self,val=None):
		_ca.put(self.chid,val,self.val)

	def monitor(self,callback=None):
		if(not callback):
			raise No_Callback_Error
		self.callback=callback
 		self.evid.append(_ca.monitor(self.chid,self.callback))

	def clear_monitor(self,evid=None):
		if(not evid):
			for i in self.evid:
				print "clearing evid",i
				_ca.clear_monitor(i)
			self.evid=[]
		else:
			_ca.clear_monitor(evid)

	def pendio(self,wait=0.0005):
		_ca.pendio(wait)

	def pend_event(self,wait=0.0005):
		_ca.pend_event(wait)

	def flush(self,wait=0.0005):
		_ca.flush(wait)

	def update_val(self,valstat):
 		self.val,self.status=valstat

	def exec_callback(self,val):
		self.callback(self,val)

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System