source: pvrrd/pvwatch.py @ 207

#!/usr/bin/env python

'''
log EPICS data into RRD files
'''

########### SVN repository information ###################
# $Date: 2010-08-26 19:55:55 +0000 (Thu, 26 Aug 2010) $
# $Author: jemian $
# $Revision: 207 $
# $HeadURL$
# $Id: pvwatch.py 207 2010-08-26 19:55:55Z jemian $
########### SVN repository information ###################

#-------------------------------------------------------------

import time
import pprint
import epics        # Matt Newville's EpicsCA support

#-------------------------------------------------------------


class pvwatch:
    '''A single monitored EPICS PV'''

    name = None        # EPICS PV name
    ch = None          # EPICS channel object
    value = None       # value at last update
    count = 0          # number of updates received
    timestamp = None   # Python time of last update
    connected = False  # current EPICS connection state

    def __init__(self, name):
        self.name = name
        self.ch = epics.PV( name,
           connection_callback = self.connectHandler,
           callback = self.updateHandler,
           auto_monitor = True)

    def __str__(self):
        n = "%s" % self.name
        v = "%s" % self.value
        c = "%d" % self.count
        return "%40s %20s %15s" % (n, v, c)

    def connectHandler(self, **kw):
        self.timestamp = time.time()
        self.connected = kw['conn']
        self.ch = kw['pv']
        # cannot call self.get() here!
        #print self.name, " connected = ", self.connected

    def updateHandler(self, **kw):
        #pprint.pprint(kw)
        self.timestamp = time.time()
        self.value = kw['value']
        self.count += 1
        #print self.name, " = ", self.value

    def get(self):
        self.value = self.ch.get()