added method for changng number of power line cycles for A/D integration

1 files changed, 31 insertions, 2 deletions

diff --git a/qolab/hardware/multimeter/hp3457a.py b/qolab/hardware/multimeter/hp3457a.py
index 226d1e2..51914bd 100644
--- a/qolab/hardware/multimeter/hp3457a.py
+++ b/qolab/hardware/multimeter/hp3457a.py
@@ -14,6 +14,7 @@ from qolab.hardware.basic import BasicInstrument
 from ._basic import Multimeter
 
 import pyvisa
+import numpy as np
 
 class HP3457A(Multimeter):
     """
@@ -46,6 +47,9 @@ class HP3457A(Multimeter):
                  'PER'#(This is here for future work)
                 ]
     
+    # Allowed number of power line cycles (defines A/D integration time)
+    NPLC = [0.0005, 0.005, .1, 1, 10, 100]
+
     # DC Volts Spec (This is here for future work)
     DCV_RES = {'30mv': {'6.5': 10e-9, '5.5': 100e-9, '4.5': 1e-6, '3.5': 10e-6},
                     '300mv': {'6.5': 100e-9, '5.5': 1e-6, '4.5': 10e-6, '3.5': 100e-6},
@@ -114,10 +118,10 @@ class HP3457A(Multimeter):
         self.read = self.resource.read
         self.write = self.resource.write
         self.read_bytes = self.resource.read_bytes
-        self.query = self.resource.query
 
         self.switchTime = 0.5  # switch time in seconds for Function/Measurement change
         self.deviceProperties.update({"Function"})
+        self.set_function('DCV')
 
 
     def get_idn(self):
@@ -148,13 +152,15 @@ class HP3457A(Multimeter):
                 print(f'[ERROR!] Couldn\'t set reading format to {format}: {e}')
         else:
             print(f'[WARNING] Entered format is not allowed. Allowed formats: {self.FORMATS}')
-
+    
+    @BasicInstrument.tsdb_append
     def get_reading(self):
         try:
             self.write(f'TARM AUTO')
             return float(self.read_bytes(16).decode().strip())
         except pyvisa.VisaIOError as e:
             print(f'[ERROR!] Error failed to get reading: {e}')
+            return np.nan()
 
     def set_beeper_status(self, status='OFF'):
         if status in self.BEEPER_STATUS:
@@ -183,6 +189,7 @@ class HP3457A(Multimeter):
             print(f"[WARNING!] Invalid measurement function '{function}'. "
                                 f"Valid functions are: {', '.join(self.FUNCTIONS)}")
 
+    @BasicInstrument.tsdb_append
     def get_temperature(self):
         try:
             self.write("TEMP?")
@@ -192,6 +199,17 @@ class HP3457A(Multimeter):
         except pyvisa.VisaIOError as e:
             print(f"[ERROR!] Error retrieving DMM's internal temperature: {e}")
 
+    def get_memory_count(self):
+        """
+        Returns the total number of stored readings.
+        """
+        try:
+            self.write(f'MCOUNT?')
+            return float(self.read_bytes(16).decode().strip())
+        except pyvisa.VisaIOError as e:
+            print(f'[ERROR!] Error failed to get count of reading in memory: {e}')
+            return np.nan()
+
     def enable_keyboard(self, status=True):
         if status:
             try:
@@ -206,7 +224,18 @@ class HP3457A(Multimeter):
             except pyvisa.VisaIOError as e:
                 print(f"[ERROR!] Error locking the DMM's keyboard: {e}")
 
+    def set_nplc(self, nplc=10):
+        if nplc in self.NPLC:
+            try:
+                self.write(f"FUNC {nplc}")
+                print(f"[INFO] NPLC is set to {nplc}")
+            except pyvisa.VisaIOError as e:
+                print(f"[ERROR!] Error setting number of power line cycles (NPLC): {e}")
+        else:
+            print(f"[WARNING!] Invalid NPLC '{nplc}'. "
+                                f"Valid NPLC values are: {', '.join(str(self.NPLC))}")
 
+        
     #-----------------------------------------------------------
     # Methods to comply with other DMM QOLab module drivers
     #-----------------------------------------------------------