hp_34401 seems to work

1 files changed, 44 insertions, 3 deletions

diff --git a/qolab/hardware/multimeter/hp_34401.py b/qolab/hardware/multimeter/hp_34401.py
index 468e966..326c162 100644
--- a/qolab/hardware/multimeter/hp_34401.py
+++ b/qolab/hardware/multimeter/hp_34401.py
@@ -2,6 +2,7 @@ from qolab.hardware.basic import BasicInstrument
 from qolab.hardware.multimeter import MultimeterSCPI
 from qolab.hardware.scpi  import SCPI_PROPERTY
 from pyvisa import constants as pyvisa_constants
+import time
 
 class HP_34401(MultimeterSCPI):
     """ HP 34401 multimeter (same as Agilent) """
@@ -17,6 +18,8 @@ class HP_34401(MultimeterSCPI):
         self.resource.data_bits = 8
         self.resource.parity = pyvisa_constants.Parity.none
         self.resource.stop_bits = pyvisa_constants.StopBits.one
+        self.resource.timeout = 5000
+        self.switchTime = 0.5 # switch time in seconds for Function/Measurement change 
         self.deviceProperties.update({'Function'})
 
     Function = SCPI_PROPERTY(scpi_prfx='SENSe:FUNCtion', ptype=str, doc="""
@@ -39,13 +42,51 @@ class HP_34401(MultimeterSCPI):
         """
      )
 
-    def toRemote():
+    def toRemote(self):
         self.write("SYSTem:REMote")
 
-    def toLocal():
+    def toLocal(self):
         self.write("SYSTem:LOCal")
 
-    Reading = SCPI_PROPERTY(scpi_prfx='SYSTem:REMote\n read', ptype=float, doc='Report current measurement', no_setter=True)
+    def isSensing(self, test):
+        return test == self.Function
+
+    Reading = SCPI_PROPERTY(scpi_prfx='SYSTem:REMote; :READ', ptype=float, doc='Report current measurement', no_setter=True)
+
+    # HP 34401 is tricky
+    # when reading over serial interface the value of measurement/function,
+    # the device need to be switched to REMOTE mode, but this leaves screen blank and unusable
+    # so we have to do the dance with toRemote and toLocal
+    def getReadingWithSettingFunction(self, desired_function_string, function_internal_name):
+        """
+        Get the reading but first check if we are set to do specific function/measurement.
+        If the instrument set to do different function, set to desired one
+        Note: the function name should be in quotes, i.e. '"Volt"'
+        """
+        if not self.isSensing(function_internal_name):
+            # print(f"function {self.Function} switching function to {desired_function_string}")
+            self.Function=desired_function_string
+            time.sleep(self.switchTime)
+        # self.toRemote() # this is done inside of Reading
+        ret = self.Reading
+        self.toLocal()
+        return ret
+
+    def getVdc(self):
+        return self.getReadingWithSettingFunction('"VOLTage:DC"', '"VOLT"')
+    def getVac(self):
+        return self.getReadingWithSettingFunction('"VOLTage:AC"', '"VOLT:AC"')
+    def getAdc(self):
+        return self.getReadingWithSettingFunction('"CURRent:DC"', '"CURR"')
+    def getAac(self):
+        return self.getReadingWithSettingFunction('"CURRent:AC"', '"CURR:AC"')
+
+
+    # Vdc     = SCPI_PROPERTY(scpi_prfx='SENSe:FUNCtion "VOLTage:DC"; :SYSTem:REMote\n read', ptype=float, doc='Report DC Voltage', no_setter=True)
+    # Vac     = SCPI_PROPERTY(scpi_prfx='SENSe:FUNCtion "VOLTage:AC"; :SYSTem:REMote\n read', ptype=float, doc='Report AC Voltage', no_setter=True)
+    # Adc     = SCPI_PROPERTY(scpi_prfx='SENSe:FUNCtion "CURRent:DC"; :SYSTem:REMote\n read', ptype=float, doc='Report DC Current', no_setter=True)
+    # Aac     = SCPI_PROPERTY(scpi_prfx='SENSe:FUNCtion "CURRent:AC"; :SYSTem:REMote\n read', ptype=float, doc='Report AC Current', no_setter=True)
+
 
 if __name__ == '__main__': 
     import pyvisa