added draft of BK_5491 multimeter

1 files changed, 140 insertions, 0 deletions

diff --git a/qolab/hardware/multimeter/bk_5491.py b/qolab/hardware/multimeter/bk_5491.py
new file mode 100644
index 0000000..9186854
--- /dev/null
+++ b/qolab/hardware/multimeter/bk_5491.py
@@ -0,0 +1,140 @@
+from qolab.hardware.basic import BasicInstrument
+from qolab.hardware.multimeter import Multimeter
+from qolab.hardware.scpi  import SCPI_PROPERTY
+from pyvisa import constants as pyvisa_constants
+import time
+
+class BK_5491(Multimeter):
+    """ BK 5491 multimeter """
+    """
+    rm = pyvisa.ResourceManager()
+    instr=rm.open_resource('ASRL/dev/ttyUSB0::INSTR')
+    Make sure to switch off the ECHO at the multimeter communication setup
+    """
+    def __init__(self, resource, *args, **kwds):
+        super().__init__(*args, **kwds)
+        self.resource = resource
+        self.config['Device model']='HP 34401'
+        self.resource.read_termination = '\r\n'
+        self.resource.baud_rate = 9600
+        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.write = self.resource.write
+        self.read = self.resource.read
+        self.query = self.resource.query
+        self.read_bytes = self.resource.read_bytes
+        self.read_binary_values = self.resource.read_binary_values
+        self.query_binary_values = self.resource.query_binary_values
+
+        self.switchTime = 0.5 # switch time in seconds for Function/Measurement change 
+        self.deviceProperties.update({})
+
+    def isPrompt(self, string):
+        if string[1] == '>':
+            return True
+        return False
+
+    def isPromptGood(self, prompt):
+        if prompt[0:2] == '=>':
+            return True
+        print(f'Error detected {prompt=}')
+        return False
+
+    def sendCmd(self, cmd_string, expect_reply=True, Nattemts=5):
+        """
+        Set command to instrument or query it readings (which is also a command)
+
+        BK_5491 in not SCPI instrument, so we get some replies (prompts *>, =>, etc)
+        even if we just send a command not a query. So we have to work around this.
+        """
+        # print(f"dbg: {cmd_string=}")
+        self.write(cmd_string)
+        if expect_reply:
+            reply = self.read() # this should be result
+            # print(f"dbg: {reply=}")
+            if self.isPrompt(reply):
+                # print(f'Error: we ask {cmd_string=} and got prompt "{reply}" instead of result')
+                prompt = reply
+                if prompt[0] == '@':
+                    if Nattemts >= 2:
+                        # print('dbg: numeric reading is not available yet, attempt one more time')
+                        time.sleep(self.switchTime)
+                        return self.sendCmd(cmd_string, expect_reply=expect_reply, Nattemts=Nattemts-1)
+                return None
+        else:
+            reply = None
+        prompt = self.read() # this should be prompt
+        self.isPromptGood(prompt)
+        # print(f"dbg: {prompt=}")
+        return reply
+
+    def getReading(self):
+       """ Report current measurement """
+       ret_string = self.sendCmd('R1')
+       # print(f'dbg: getReading received "{ret_string}"')
+       return float(ret_string)
+
+    def setFunction(self, key_string):
+        """
+        BK_5491 set the measurement functions according to the front panel keys:
+            K1 - Vdc
+            K2 - Adc
+            K3 - Vac
+            K4 - Aac
+            K5 - Resistance
+            K6 - Diode
+            K7 - Frequency (Hz)
+            K8 - Auto
+            K9 - Up key
+            K10 - Down key
+            K11 - MinMax key
+            K12 - Hold key
+            K13 - Local (manual does not specify, but it works this way)
+            K14 - Rel key
+            K15 - Shift key
+            K16 - 2nd key
+            K17 - Vdc and Vac keys simultaneously
+            K18 - Adc and Aac keys simultaneously
+            K19 - Shift then Up keys (increasing the intensity of the VFD display)
+            K20 - Shift then Down keys (decreasing the intensity of the VFD display)
+        """
+
+    def getVdc(self):
+        self.sendCmd('K1')
+        return self.getReading()
+    def getVac(self):
+        self.sendCmd('K3')
+        return self.getReading()
+    def getAdc(self):
+        self.sendCmd('K2')
+        return self.getReading()
+    def getAac(self):
+        self.sendCmd('K4')
+        return self.getReading()
+    def getResistance(self):
+        self.sendCmd('K5')
+        return self.getReading()
+    def getDiode(self):
+        self.sendCmd('K6')
+        return self.getReading()
+    def getFreq(self):
+        self.sendCmd('K7')
+        return self.getReading()
+
+    def toLocal(self):
+        self.sendCmd('K13', expect_reply=False)
+
+
+if __name__ == '__main__': 
+    import pyvisa
+    print("testing")
+    rm = pyvisa.ResourceManager()
+    print(rm.list_resources())    
+    instr=rm.open_resource('ASRL/dev/ttyUSB0::INSTR')
+    multimeter = BK_5491(instr)
+    print('------ Header start -------------')
+    print(str.join('\n', multimeter.getHeader()))
+    print('------ Header ends  -------------')