我对Python非常陌生,我在使用Python的某些方面遇到了困难
我正在编写代码,用pyvisa控制几个仪器。为了简单起见,我这里只展示了一种仪器(Thor Labs功率计)。如果我把我所有的代码放在一个文件中,我就可以让事情顺利进行。下面的代码首先搜索可用仪器,并定义仪器ID(ThorID):
import pyvisa
rm = pyvisa.ResourceManager() # Set up resource manager
resource_list = rm.list_resources() # Create a list of available instruments
# Thor Labs power meters should contain this string
Thor_str = "0x1313::0x8079"
# Search for a Thor Labs meter in the resource list
Thor = [i for i, s in enumerate(resource_list) if Thor_str in s]
if len(Thor) == 0:
print("No Thor Labs power meter detected")
ThorID = ""
else:
print("Thor Labs power meter detected")
ThorID = resource_list[Thor[0]] # This is the Thor Labs VISA ID
然后我定义了类功率计
class powermeter:
"Power meter class. Contains parameter values and commands."
def __init__(self, wavelength=450, meter_range=200e-3, id=ThorID):
""" Define default parameter values """
self.wavelength = wavelength # nm
self.meter_range = meter_range # W
self.ID = id # Meter's VISA ID
self.name = "" # Meter instance name
def connect(self):
"""Open a connection to the power meter"""
self.name = rm.open_resource(self.ID)
def set_wavelength(self, wavelength):
"""Set the power meter wavelength (nm)"""
self.name.write("CORR:WAV " + str(wavelength))
def set_range(self, meter_range):
"""Set the power meter range (W)"""
self.name.write("POW:DC:RANG " + str(meter_range))
def read(self):
"""Read the power meter output (mW)"""
return float(self.name.query("READ?"))*1000
最后3条线路打开与仪表的连接,并设置波长(至400 nm)。我可以在一个.py文件中确认所有这些代码都有效
enter pm = powermeter() # Create instance of powermeter
pm.connect() # Connect to this power meter
pm.set_wavelength(400) # Set wavelength to 400 nm
我在尝试将类拆分为一个单独的.py文件时遇到了很多麻烦。我想这样做是为了让我的代码更整洁……最终我会添加一个GUI和另一个类,我不想要一个庞大而繁琐的文本
我天真的第一次尝试将此作为主要代码,上面编写的类保存在PM_class.py中:
import pyvisa
rm = pyvisa.ResourceManager() # Set up resource manager
resource_list = rm.list_resources() # Create a list of available instruments
# Thor Labs power meters should contain this string
Thor_str = "0x1313::0x8079"
# Search for a Thor Labs meter in the resource list
Thor = [i for i, s in enumerate(resource_list) if Thor_str in s]
if len(Thor) == 0:
print("No Thor Labs power meter detected")
ThorID = ""
else:
print("Thor Labs power meter detected")
ThorID = resource_list[Thor[0]] # This is the Thor Labs VISA ID
from PM_class.py import powermeter
但是我在PM_class.py-NameError中得到一个错误:没有定义名称“ThorID”
我不明白这一点,因为在我尝试导入类之前,ThorID在行中有明确的定义
任何关于如何实现这一点的建议都是非常受欢迎的
类功率计位于另一个模块中, 在这个字符串中
您尝试使用var
ThorID
初始化它,但该类本身已被封装,无法从当前模块读取该var。尝试在PM_class.py
中定义ThorID
变量或使用并在初始化类时传递id
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