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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.
"""
self.resource.read_bytes( self.resource.bytes_in_buffer ) # clear read buffer
# 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 -------------')
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