multiple-pulse capability enabled

The capability to emit multiple pulses per sequence step was added to the driver. For this, the sweep mode was misused by setting start and stop voltage/current to the same value. 

As this also works for a single pulse as well as the DC mode, the initialization was modified to have the B290xB SMU run in the sweep mode all the time, even if the pulse count in the GUI is set to 1 or if the SMU is used for DC output. No drawbacks were observed in practical use other than that the symbol on the display of the SMU shows a sweep rather than a DC or pulse graphic.

src/SMU-Agilent_B29xx/main.py

@@ -35,6 +35,8 @@
 
 from pysweepme.EmptyDeviceClass import EmptyDevice
 
+import time
+
 
 class Device(EmptyDevice):
 
@@ -84,12 +86,14 @@ def set_GUIparameter(self):
             "PulseOnTime": 1e-3,  # for use on the B2902B, defined as the pulse width time
             "PulseDelay": 0,  # for use on the B2902B, defined as the delay time prior to pulse
             "PulseOffLevel": 0.0,  # bias voltage during pulse-off
+            "PulseCount": 1, #amount of pulses
             # "Average": 1, # not yet supported
         }
 
         return gui_parameter
 
     def get_GUIparameter(self, parameter={}):
+        #print(parameter)
 
         self.four_wire = parameter['4wire']
         # self.route_out = parameter['RouteOut']
@@ -124,10 +128,13 @@ def get_GUIparameter(self, parameter={}):
 
         # bias voltage during pulse-off
         self.pulseofflevel = parameter["PulseOffLevel"]
+
+        # amount of pulses to be automatically released
+        self.pulsecount = parameter["PulseCount"]
 
         # pulse delay is part of trigger acquire delay; this equation makes sure than the minimum acquire delay of
-        # 750us is extended by the amount of pulse delay requested by the user via the GUI
-        self.acqdelay = str("{:.4E}".format(self.toff + 750e-6))
+        # 500us is extended by the amount of pulse delay requested by the user via the GUI
+        self.acqdelay = str("{:.4E}".format(self.toff + 500e-6))
 
     def initialize(self):
         # once at the beginning of the measurement
@@ -155,8 +162,8 @@ def configure(self):
         if self.source.startswith("Voltage"):
             self.port.write(":SOUR%s:FUNC:MODE VOLT" % self.channel)
             # sourcemode = Voltage
-            self.port.write(":SOUR%s:VOLT:MODE FIX" % self.channel)
-            # sourcemode fix
+            self.port.write(":SOUR%s:VOLT:MODE SWE" % self.channel)
+            # sourcemode sweepo
             self.port.write(":SENS%s:FUNC \"CURR\"" % self.channel)
             # measurement mode
             self.port.write(":SENS%s:CURR:PROT %s" % (self.channel, self.protection))
@@ -170,10 +177,11 @@ def configure(self):
             # Autorange for current output
 
         elif self.source.startswith("Current"):
+
             self.port.write(":SOUR%s:FUNC:MODE CURR" % self.channel)
             # sourcemode = Voltage
-            self.port.write(":SOUR%s:CURR:MODE FIX" % self.channel)
-            # sourcemode fix
+            self.port.write(":SOUR%s:CURR:MODE SWE" % self.channel)
+            # sourcemode sweep
             self.port.write(":SENS%s:FUNC \"VOLT\"" % self.channel)
             # measurement mode
             self.port.write(":SENS%s:VOLT:PROT %s" % (self.channel, self.protection))
@@ -222,11 +230,10 @@ def configure(self):
             self.port.write(":FUNC PULS")  # switch to pulse output instead of "DC"
             self.port.write(":PULS:WIDT %s" % self.ton)  # pulse width time
             self.port.write(":PULS:DEL %s" % self.toff)  # delay prior to pulse
-            self.port.write(
-                ":SOUR%s:FUNC:TRIG:CONT OFF" % self.channel)  # switch off continuous operation of internal trigger
+            self.port.write(":SOUR%s:SWE:POIN %s" % (self.channel,self.pulsecount)) # setting the amount of pulses by mis-using the sweep function
+            self.port.write(":SOUR%s:FUNC:TRIG:CONT OFF" % self.channel)  # switch off continuous operation of internal trigger
             self.port.write(":SOUR%s:WAIT ON" % self.channel)  # enables to wait for any change of amplitude past pulse
-            self.port.write(
-                ":SENS%s:WAIT ON" % self.channel)  # enables wait time for start of measurement defined by delay
+            self.port.write(":SENS%s:WAIT ON" % self.channel)  # enables wait time for start of measurement defined by delay
             self.port.write(":TRIG%s:TRAN:DEL MIN" % self.channel)  # trigger delay hardcoded to 0s
 
             # delay of measurement after pulse release is triggered; takes care of ramp-up
@@ -235,6 +242,8 @@ def configure(self):
             self.port.write(":TRIG%s:ALL:COUN 1" % self.channel)  # sets trigger count, 1 for single pulse
             self.port.write(":TRIG%s:LXI:LAN:DIS:ALL" % self.channel)  # disable LXI triggering
             self.port.write(":TRIG%s:ALL:SOUR AINT" % self.channel)  # enable internal trigger
+
+            self.port.write(":TRIG%s:ALL:COUN %s" % (self.channel, self.pulsecount)) # enables multiple trigger events for the requested amount of pulses
 
             # set trigger daly to minimum; not to be mixed up with pulse delay
             self.port.write(":TRIG%s:ALL:TIM MIN" % self.channel)
@@ -390,16 +399,43 @@ def apply(self):
         value = str("{:.4E}".format(self.value))  # makes sure that self.value fits into SCPI command in terms of length
         if self.pulse:
             # get channel ready at specified values
+
             self.port.write(":SOUR%s:%s %s" % (self.channel, self.commands[self.source], self.pulseofflevel))
-            # arming the pulse trigger
-            self.port.write(":SOUR%s:%s:TRIG %s" % (self.channel, self.commands[self.source], value))
+
+            # arming the pulse trigger; mis-using the sweep function with identical start and stop values so we can use number-of-pulses functionality
+            if self.source.startswith("Current"):
+                self.port.write(":SOUR%s:CURR:STAR %s" % (self.channel, value))
+                self.port.write(":SOUR%s:CURR:STOP %s" % (self.channel, value))
+
+            if self.source.startswith("Voltage"):
+                self.port.write(":SOUR%s:VOLT:STAR %s" % (self.channel, value))
+                self.port.write(":SOUR%s:VOLT:STOP %s" % (self.channel, value))
+
             # releasing the pulse trigger
             self.port.write(":INIT (@%s)" % self.channel)
+
         else:
             # set output to specified values
             self.port.write(":SOUR%s:%s %s" % (self.channel, self.commands[self.source], value))
 
     def call(self):
+
+        if self.pulse:
+            opcounter = 0                                                    # set counter for operation register request loop back to zero
+
+            while True:
+                self.port.write(":STAT:OPER:COND?")                           # query SMU for the status of the operation register
+                opstatus=self.port.read()
+                print("Operation Status:", opstatus)
+                if opstatus=="1170":                                          # checks whether transition and aquisition are finished on both channels (INT values 2+16 + 128+1024)
+                    break
+                else:
+                    opcounter += 1
+                    time.sleep(0.5)
+
+
+        #if self.pulse:
+        #    time.sleep(round(self.pulsecount * (0.04 + self.ton + self.toff),1)) # prevents visa timeout as the device won't response during pulse sweep, not even to OPC command. A generous 40ms minimum delay between pulses is assumed.
 
         if self.pulse:
             self.port.write(