autoEncoder.py

#!/usr/bin/env python
# Scott Stubbs - code to allow pnCCD encoders to turn on and off automatically.
# Based on SXR scanning scripts by A. Mitra et al.

from __future__ import (absolute_import, division, print_function)

import pyca
from Pv import Pv

import sys
import time
import random
import threading
from numbers import Number

import argparse

class donemoving(Pv):
  def __init__(self, name):
    Pv.__init__(self, name)
    self.monitor_cb = self.monitor_handler
    self.__sem = threading.Event()

  def wait_for_done(self):
    moving = False
    while not moving:
      self.__sem.wait(0.1)
      if self.__sem.isSet():
        self.__sem.clear()
        if self.value == 0:
          moving = True
      else:
        print('timedout while waiting for moving')
        break
    while moving:
      self.__sem.wait(1500)
      if self.__sem.isSet():
        self.__sem.clear()
        if self.value == 1:
          moving = False
      else:
        print('timedout while waiting for done')
        break

  def monitor_handler(self, exception=None):
    try:
      if exception is None:
        print('pv %s is %d' %(self.name, self.value))
        self.__sem.set()
      else:
        print("%-30s " %(self.name), exception)
    except Exception as e:
      print(e)

if __name__ == '__main__':
  parser = argparse.ArgumentParser(description='pnCCD encoder automation, will turn encoder on, move motor in specified direction and turn back off again')
  parser.add_argument('motor', metavar='motor', help='PV of motor name')
  parser.add_argument('encoder', metavar='encoder', help='PV of encoder')
  parser.add_argument('move_direction', metavar='move_direction', help='+ moves positive, - negative, or number for specific position')
  try:
      args=parser.parse_args()
  except:
     sys.exit("Check arguments!")  #Likely no arguments passed in

  motor_prefix = args.motor
  encoderpv = Pv(args.encoder)
  evtmask = pyca.DBE_VALUE | pyca.DBE_LOG | pyca.DBE_ALARM 
  try:
    "SETTING TWEAK PV"
    if args.move_direction == '+':
        print("Positive tweak")
        motorpv = Pv(motor_prefix + '.TWF')
    elif args.move_direction == '-':
        print("Negative tweak")
        motorpv = Pv(motor_prefix + '.TWR')
    elif isinstance(args.move_direction, Number):
        print("Move to %d" % args.move_direction)
        motorpv = Pv(motor_prefix)
    else:
        sys.exit("Check options, no direction/position found!")
# Connect motor, proc, dmov and encoder PVs - proc needed to tell IOC encoder is on
    motorpv.connect(1.0)
    motor_statpv = Pv(motor_prefix + ':UPDATE_STATUS.PROC')
    motor_statpv.connect(1.0)
    dmovpv = donemoving(motor_prefix + '.DMOV')
    dmovpv.connect(1.0)
    dmovpv.monitor(evtmask, ctrl=False)
    encoderpv.connect(1.0)
    pyca.flush_io()
#  Put to encoder PV to turn it on, wait briefly
    encoderpv.put('1', 2.0)
    time.sleep(0.5)
#  Tell IOC to update status
    motor_statpv.put(1, 2.0)
    time.sleep(0.5)
#  Put to motor VAL for specific position or tweak PV
    if isinstance(args.move_direction, Number):
        motorpv.put(args.move_direction, 2.0)
    else:
        motorpv.put(1, 2.0)
    dmovpv.wait_for_done()
#  Once motor is done moving, turn encoder back off!
    encoderpv.put('0', 2.0)
# Verify
    encoderpv.get(False, 1.0) # Don't need control values
    if encoderpv.value == 0:
        print("Encoder off!")
    else:
        print("Encoder may not be off. Try manually.")
# Cleanup
    dmovpv.disconnect()
    motorpv.disconnect()
    encoderpv.disconnect()
    motor_statpv.disconnect()

  except pyca.pyexc as e:
      print('pyca exception: %s' %(e))
  except pyca.caexc as e:
      print('channel access exception: %s' %(e))