Startup

script/keithley.py

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+import ch.psi.epics as epics
+
+class Keithley(object):
+    def __init__(self, basename):
+        self.basename = basename
+        self.scanCh = None
+        self.ttypeCh = None
+        self.nplcCh = None
+        self.navgCh = None
+        self.tottimeCh = None
+        self.doinitCh = None
+        self.dotriggerCh = None
+        self.dofetchCh = None
+        self.readoutCh = None
+        
+    def initialize(self):
+        self.scanCh = epics.ChannelInteger(basename + "READSCAN.SCAN")
+        self.ttypeCh = epics.ChannelInteger(basename + "TTYPE")
+        self.nplcCh = epics.ChannelDouble(basename + "NPLC")
+        self.navgCh = epics.ChannelInteger(basename + "NAVG")
+        self.tottimeCh = epics.ChannelDouble(basename + "TOTTIME")
+        self.doinitCh = epics.ChannelInteger(basename + "DOINIT")
+        self.dotriggerCh = epics.ChannelInteger(basename + "DOTRIGGER")
+        self.dofetchCh = epics.ChannelInteger(basename + "DOFETCH")
+        self.readoutCh = epics.ChannelDouble(basename + "READOUT")
+    
+    def prepare(self, dwell):
+        """
+        prepare keithley for gpib polling:
+        scan passive, bus triggered, set dwell time
+        
+        dwell = dwell time in seconds (0.1 - 20.0)
+        """
+        self.scanCh.putq(0)
+        self.ttypeCh.putq(2)
+        nplc = 5.
+        navg = dwell / 0.1
+        if navg > 100:
+            nplc *= 2
+            navg /= 2
+        navg = min(navg, 100)
+        nplc = min(nplc, 10.)
+        self.nplcCh.putq(nplc)
+        self.navgCh.putq(navg)
+
+    def trig(self):
+        """
+        trigger keithleys, wait until done, and read the result into EPICS.
+        the value can then be read by pshell from the channel.
+        """
+        dwell1 = caget(KEI_SAMPLE + "TOTTIME") / 1000.
+        dwell2 = caget(KEI_REF + "TOTTIME") / 1000.
+        dwell = max(dwell1, dwell2)
+        self.doinitCh.put(1)
+        self.dotriggerCh.put(1)
+
+    def get_dwell(self):
+        """
+        get dwell time in seconds.
+        """
+        dwell = self.tottimeCh.get() / 1000.
+        return dwell
+    
+    def fetch(self):
+        """
+        fetch the current value from the keithley into EPICS.
+        """
+        #time.sleep(self.get_dwell())
+        self.dofetchCh.put(1)
+
+    def read(self):
+        """
+        read the curent value.
+        """
+        return self.readoutCh.get()
+        
+    def release(self):
+        """
+        switch keithleys to free run.
+        0.1 s polling and dwell time
+        """
+        self.nplcCh.putq(nplc)
+        self.navgCh.putq(navg)
+        self.scanCh.putq(9)
+        self.ttypeCh.putq(0)
+
+KeiSample = Keithley("X03DA-KEITHLEY-1:")
+KeiReference = Keithley("X03DA-KEITHLEY-2:")
+
+KeiSample.initialize()
+KeiReference.initialize()

script/test/ManipulatorScanKei.py

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+"""
+Arguments:
+
+MOTOR (device)
+SENSORS (list)
+RANGE (tuple (min, max))
+STEPS (int or tuple)
+LATENCY (double)
+RELATIVE (BOOLEAN)
+"""
+
+MOTOR = (ManipulatorY)
+SENSORS (SampleCurrent, RefCurrent)
+RANGE = (-0.5, 0.5)
+STEPS = 10
+LATENCY = 0.5
+RELATIVE = True
+
+adjust_sensors()
+set_adc_averaging()
+before_scan()
+set_preference(Preference.PLOT_TYPES, {'Scienta spectrum':1})
+
+try:
+    lscan(MOTOR, SENSORS, RANGE[0], RANGE[1], STEPS, LATENCY, RELATIVE, before_read=before_readout, after_read = after_readout)
+finally:
+    if ENDSCAN:
+        after_scan()    
+