Closedown

script/keithley.py

@@ -62,13 +62,34 @@ class Keithley(object):
         2) set user mode, set range
         
         """
-        self.dosetdefaultCh.write(1)
-        self.scanCh.write(9)
+        #self.dosetdefaultCh.write(1)
+        #self.scanCh.write(9)
         
     def prepare(self, dwell, triggered):
+        """
+        prepare keithley for gpib polling.
+
+        setting keithley parameters has several issues.
+        the dwell time and trigger mode cannot be set programmatically at the moment.
+        the user should select poll slow (100 ms), medium (20 ms) or fast (2 ms).
+        this method just reads the current value and stores it in self.dwell.
+        
+        dwell: dwell time in seconds.
+            0.1 - 20.0 in triggered mode,
+            0.1 - 1.0 in free running mode.
+        triggered:
+            True: wait for self.trig call and trigger once per call.
+            False: 1 Hz free run using EPICS SCAN attribute.
+        """
+        self.triggered = False
+        self.dwell = self.tottimeCh.read() / 1000.
+
+    def prepare_not_working(self, dwell, triggered):
         """
         prepare keithley for gpib polling:
         scan passive, bus triggered, set dwell time
+
+        this doesn't to work.
         
         dwell: dwell time in seconds.
             0.1 - 20.0 in triggered mode,
@@ -142,6 +163,7 @@ class Keithley(object):
         _do nothing for now!_
         """
         return None
+        
         self.nplcCh.write(5.)
         self.navgCh.write(1.)
         self.scanCh.write(6)