KepcoMotorController.py

import visa, time

from sardana import State
from sardana.pool.controller import MotorController
from sardana.pool.controller import Type, Description, DefaultValue


class KepcoMotorController(MotorController):
    ctrl_properties = {'resource': {Type: str, Description: 'GPIB resource', DefaultValue: 'GPIB0::6::INSTR'}}
    
    MaxDevice = 1
    
    def __init__(self, inst, props, *args, **kwargs):
        super(kepcoController, self).__init__(
            inst, props, *args, **kwargs)

        self.rm = visa.ResourceManager('@py')
        self.inst = self.rm.open_resource(self.resource)
        print 'Kepco Initialization'
        idn = self.inst.query('*IDN?')
        if idn:
            print idn
            print 'Kepco is initialized!'
        else:
            print 'Kepco is NOT initialized!'
        # initialize hardware communication        
        self._motors = {}
        self._isMoving = None
        self._moveStartTime = None
        self._threshold = 0.1
        self._target = None
        self._timeout = 10

    def AddDevice(self, axis):
        self._motors[axis] = True
        self.inst.write('FUNC:MODE CURR')
        self.inst.write('CURR:MODE FIX')
        self.inst.write('CURR:LIM:NEG 5')
        self.inst.write('CURR:LIM:POS 5')
        self.inst.write('OUTP ON')

    def DeleteDevice(self, axis):
        del self._motors[axis]

    def StateOne(self, axis):
        limit_switches = MotorController.NoLimitSwitch
        pos = self.ReadOne(axis)
        now = time.time()
        
        if self._isMoving == False:
            state = State.On
        elif self._isMoving & (abs(pos-self._target) > self._threshold): 
            # moving and not in threshold window
            if (now-self._moveStartTime) < self._timeout:
                # before timeout
                state = State.Moving
            else:
                # after timeout
                self._log.warning('Kepco Timeout')
                self._isMoving = False
                state = State.On
        elif self._isMoving & (abs(pos-self._target) <= self._threshold): 
            # moving and within threshold window
            self._isMoving = False
            state = State.On
            #print('Kepco Tagret: %f Kepco Current Pos: %f' % (self._target, pos))
        else:
            state = State.Fault
        
        return state, 'some text', limit_switches

    def ReadOne(self, axis):
        res = float(self.inst.query('MEAS:CURR?'))
        time.sleep(0.001)
        return res

    def StartOne(self, axis, position):
        self._moveStartTime = time.time()
        self._isMoving = True
        self._target = position
        cmd = 'CURR {:f}'.format(position)
        time.sleep(0.01)
        self.inst.write(cmd)

    def StopOne(self, axis):
        pass

    def AbortOne(self, axis):
        pass