electronsourcecontroller2-tspspi

Custom electron gun slow control Python communication library and GUI utlity

Work in progress

Communication library

The communication library from eguncom.py implements most of the communication protocol with the electron beam slow-control system.

class ElectronGunControl

The ElectronGunControl class implements asynchronous and synchronous communication with the serially / USB attached control system. The port file is passed to the constructor

ctrl = ElectronGunNotConnected(portFile = '/dev/...')

When no port file is passed it defaults to /dev/ttyU0.

The exposed public methods are:

Method	Description	Synchronous	Asynchronous callback
id()	Queries the current version	with sync = True	cbIdentify(controller, versionDate, versionRevision)
getPSUVoltage(channel)	Queries the current voltage on the given channel	with sync = True	cbVoltage(controller, channel, voltageVolts)
getPSUCurrent(channel)	Queries the current current on the given channel	with sync = True	cbCurrent(controller, channel, currentMicroamps)
getPSUModes()	Checks if PSUs are off, in voltage limited or current limited mode	with sync = True	cbPSUMode(controller, states)
getFilamentCurrent()	Queries the filament current	with sync = True	cbFilamentCurrent(controller, current)
off()	Disabled all high voltage and filament currents
setPSUPolarity(channel, polarity)	Sets polarity to POLARITY_POS or POLARITY_NEG
setPSUEnable(channel)	Enables the given PSU channel
setPSUDisable(channel)	Disables the given PSU channel
setPSUVoltage(channel, voltage)	Sets the given channel to the given voltage
setFilamentCurrent(currentMa)	Sets the filament current or target current to the specified milliamps
setFilamentOn()	Enabled the filament supply
setFilamentOff()	Disabled the filament supply
runInsulationTest()	Runs an insulation test with low current limits	with sync = True	cbInsulation(isOk, listOfShorts)
beamOn()	Runs the slow beam on sequence (slowly heating filament to previously set setFilamentCurrent, ramping up voltages)	with sync = True	cbBeamon()

Usage example

Synchronous sample (USB / serial)

Example to perform a synchronous:

• Insulation check
• Startup for 100 mA beam current
• Looping through focus voltages
• Shutting down

with ElectronGunControl() as ctrl:
    # Currently a hack to wait for the control system to reset when using the
    # primary port

    time.sleep(5)

    # We want to see the voltages reported by the system so we
    # define a lambda that just prints the voltages while ramping up
    # during insulation test and beam on sequence

    ctrl.cbVoltage = lambda c,chan,v : print("Voltage for channel {} is {} V".format(chan, v))

    # Query it's identity
    ret = ctrl.id(sync = True)
    print("ID call returned {}".format(ret))

    # Run insulation test
    print("Running insulation test")
    ret = ctrl.runInsulationTest(sync = True)
    print("Insulation test returned: {}".format(ret))

    # Run beam on sequence ...
    ret = ctrl.beamOn(sync = True)
    print("Beam on successfully returned: {}".format(ret))

    print("Sweeping focus voltage")
    for focusVoltage in range(1750,1950):
        print("New focus voltage {}".format(focusVoltage))
        ctrl.setPSUVoltage(3, focusVoltage)
        time.sleep(1)

    ctrl.off()
    print("Off, done ...")