Implemented basic VNA functionality as methods

Python script/VNA.py

@@ -3,7 +3,7 @@ import time
 
 
 class Vna:
-    def __init__(self):
+    def __init__(self, ip_address):
         """
                 Implements the basic operation of the VNA
 
@@ -11,81 +11,171 @@ class Vna:
         # open connection here
 
         # store the credentials so that methods can access them
-        #self.__ip_address = ip_address
+        self.__ip_address = ip_address
 
-        # we try to connect to the climate chamber just to see if there is an error
+        # we try to connect to the VNA just to see if there is an error
         self.rm = pyvisa.ResourceManager()
 
-        self.vna = self.rm.open_resource("TCPIP0::192.168.115.39 ::57732::SOCKET")
-        # self.vna.write_termination = '\r\n'
-        # self.vna.read_termination = '\r\n'
+        self.vna = self.rm.open_resource("TCPIP::" + self.__ip_address + "::5025::SOCKET")
+        self.vna.write_termination = '\r\n'
+        self.vna.read_termination = '\n'
         self.vna.timeout = 5000
 
         # Preset the VNA and wait for preset completion via use of *OPC?
-        self.vna.write("SYST:PRES; *OPC?")
-        self.vna.read()
+        self.preset_vna()
 
         # Clear the event status registers and empty the error queue
-        self.vna.write("*CLS")
+        self.clear_status()
 
-        # Query identification string *IDN? 
-        self.vna.write("*IDN?")
-        print(self.vna.read())
+    def get_tuples_of_current_traces(self):
+        """
+        Returns list of tuples containing trace and measured parameter pairs
 
-        # check the error queue
-        self.vna.write("SYST:ERR?")
-        print(self.vna.read())
+        :return: list of tuples
+        """
+        traces = self.get_current_traces()
+        result = []
+        for i in range(0, len(traces)):
+            if i % 2 == 0:
+                result.append((traces[i], traces[i + 1]))
+        return result
+
+    def get_current_traces(self):
+        """
+        Returns list of string containing traces and measured parameters
 
-        # the communication section
+        :return: list of strings
+        """
+        return self.vna.query("CALC1:PAR:CATALOG?").replace("'", "").split(',')
 
-        # Select the default measurement name as assigned on preset. To catalog the measurement names, 
-        # by channel number, use the 'CALCulate[n]:PARameter:CATalog?' command where [n] is the channel 
-        # number. 
-        self.vna.write("CALC:PAR:SEL 'CH1_S11_1'")
+    def create_new_trace(self, name, parameter):
+        """
+        Creates new trace
 
-        # Set data transfer format to ASCII
-        self.vna.write("FORM:DATA ASCII")
+        Parameters
+        ----------
+        name : str
+            Name of new trace.
+        parameter : int
+            Measured parameter.
+
+        Returns
+        -------
+        None.
 
-        # Alter measure from S11 to S21
-        self.vna.write("CALC:PAR:MOD S21")
+        """
+        self.vna.write("CALC1:PAR:SDEF '" + name + "', '" + parameter + "'")
+
+    def set_trace_measurements(self, trace, measurement):
+        """
+        Set measured parameter of given trace
 
-        # Loop to control the number of trace points, provide single sweep synchronization, query the data,
-        # indicate number of points and indicate number of characters in the trace read. 
-        self.traceData = []
-        i = 0
-        self.numPointsList = [201, 401, 801, 1601, 3201, 6401, 12801, 20001, 32001, 100001]
+        Parameters
+        ----------
+        trace : str
+            Name of new trace.
+        measurement : int
+            Measured parameter.
 
-        while i < len(self.numPointsList):
-            # Set number of points by list value
-            self.numPoints = self.numPointsList[i]
-            self.vna.write("SENS:SWE:POIN " + str(self.numPoints) + ";*OPC?")
-            self.vna.read()
+        Returns
+        -------
+        None.
 
-            self.startTime = self.time.clock()
-            # Trigger assertion with hold-off for trigger complete via *OPC?
-            self.vna.write("SENS:SWE:MODE SING;*OPC?")
-            self.vna.read()
+        """
+        self.vna.write("CALC1:PAR:MEAS '" + trace + "', '" + measurement + "'")
 
-            self.stopTime = self.time.clock() - self.startTime
+    def set_sweep_points(self, points):
+        return self.vna.query("SENS1:SWE:POIN " + str(points) + ";*OPC?")
 
-            # The SDATA assertion queries underlying real and imaginary pair data
-            self.vna.write("CALC:DATA? SDATA")
-            self.traceData = self.vna.read()
+    def check_error_queue(self):
+        """
+        Check the error queue. Initially *CLS asserted in beginning of program.
+        The application should run from stem to stern error free. The final error
+        queue query should return '+0, No Error', else the application has potentially
+        caused a correctable error!.
+        """
+        return self.vna.query("SYST:ERR?")
 
-            print("Time to sweep = " + str(self.stopTime))
-            print("Number of trace points set = " + str(self.numPoints))
-            print("Number of characters in returned data " + str(len(self.traceData)))
-            print(self.traceData)
+    def query_identification(self):
+        return self.vna.query("*IDN?")
 
-            i = i + 1
+    def set_active_trace(self, trace):
+        """
+        Selects active trace
+
+        Parameters
+        ----------
+        trace : str
+            Name of trace.
+        """
+        self.vna.write("CALC1:PAR:SEL '" + trace + "'")
+
+    def set_sweep_mode(self, mode):
+        """
+        Trigger assertion with hold-off for trigger complete via *OPC?
 
-        # Check the error queue. Initially *CLS asserted in beginning of program. 
-        # The application should run from stem to stern error free. The final error 
-        # queue query should return '+0, No Error', else the application has potentially
-        # caused a correctable error!. 
-        self.vna.write("SYST:ERR?")
-        print(self.vna.read())
+        Parameters
+        ----------
+        mode : str
+            Sweep mode.
+        """
+        return self.vna.query("SENS1:SWE:MODE " + mode + "; *OPC?")
+
+    def get_measurement_string(self, trace, result_format):
+        """
+        Returns string of measured values
+
+        Parameters
+        ----------
+        trace : str
+            Name of trace.
+        result_format : str
+            VNA format of returned result.
+
+        Returns
+        -------
+        None.
+
+        """
+        # Set data transfer format to ASCII
+        self.vna.write("FORM:DATA ASCII")
+        return self.vna.query("CALC1:DATA:TRAC? '" + trace + "', " + result_format + "")
+
+    def get_list_of_measurement_values(self, trace, result_format):
+        """
+        Returns list of measured values
+
+        Parameters
+        ----------
+        trace : str
+            Name of trace.
+        result_format : str
+            VNA format of returned result.
+
+        Returns
+        -------
+        None.
+
+        """
+        measurements = self.get_measurement_string(trace, result_format)
+        result = []
+        for x in measurements.split(',')[10:]:
+            if x != '0' and x != '-999':  # no value is indicated with 0 for SDAT and -999 for FDAT
+                result.append(float(x))
+        return result
+
+    def clear_status(self):
+        """
+        Clear the event status registers and empty the error queue
+        """
+        self.vna.write("*CLS")
+
+    def preset_vna(self):
+        self.vna.write("SYST:PRES; *OPC?")
+        self.vna.read()
 
-        # Close the VISA connection
+    def close(self):
         self.vna.close()
 
+    def __del__(self):
+        self.close()