1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
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 -------------')
|
