Python nidaqmx读取K热电偶值

Question

我是一个Python新手，但通常通过修改示例来满足我有限的需求。

我正在尝试使用NI 9213和NI CDAQ 9714来自动化一些温度测量

我观看了来自NI的视频，并能够进行一般测量

https://www.youtube.com/watch?v=NMMRbPvkzFs

但是，我不能正确指定热电偶的类型。

导入nidaqmx

nidaqmx.constants.ThermocoupleType(10073) nidaqmx.constants.TemperatureUnits(10143)

使用nidaqmx.Task()作为任务：

task.ai_channels.add_ai_thrmcpl_chan("cDaq1Mod1/ai0:1")
#task.ai_channelsadd_ai_thrmcpl_chan("cDaq1Mod1/ai0:1","bob", 0.0, 100.0,units="TemperatureUnits.DEG_C: 10143", thermocouple_type="ThermocoupleType.J: 10072")

data=task.read(1,1.0)

print (data[0])

从这里开始http://nidaqmx-python.readthedocs.io/en/latest/ai_channel_collection.html

我就是想不出如何设置热电偶的单位和类型。

我可以使用命令来设置它们，但是我不能在添加热电偶命令中引用它们

我使用的是Anaconda Spyder 3.6

add_ai_thrmcpl_chan(physical_channel，name_to_assign_to_channel=u''，min_val=0.0，max_val=100.0，units=，thermocouple_type=，cjc_source=，cjc_val=25.0，cjc_channel=u‘’)源

Creates channel(s) that use a thermocouple to measure temperature.
Parameters: 

    physical_channel (str) – Specifies the names of the physical channels to use to create virtual channels. The DAQmx physical channel constant lists all physical channels on devices and modules installed in the system.
    name_to_assign_to_channel (Optional[str]) – Specifies a name to assign to the virtual channel this function creates. If you do not specify a value for this input, NI-DAQmx uses the physical channel name as the virtual channel name.
    min_val (Optional[float]) – Specifies in units the minimum value you expect to measure.
    max_val (Optional[float]) – Specifies in units the maximum value you expect to measure.
    units (Optional[nidaqmx.constants.TemperatureUnits]) – Specifies the units to use to return temperature measurements.
    thermocouple_type (Optional[nidaqmx.constants.ThermocoupleType]) – Specifies the type of thermocouple connected to the channel. Thermocouple types differ in composition and measurement range.
    cjc_source (Optional[nidaqmx.constants.CJCSource]) – Specifies the source of cold-junction compensation.
    cjc_val (Optional[float]) – Specifies in units the temperature of the cold junction if you set cjc_source to CONSTANT_VALUE.
    cjc_channel (Optional[str]) – Specifies the channel that acquires the temperature of the thermocouple cold- junction if you set cjc_source to CHANNEL.

任何建议都非常感谢。这么简单的事情，但我遇到了障碍，看不到任何直接相关的例子。

非常感谢

加文

Answer 1

我也遇到过同样的问题。

解决方案是在add_ai_thrmcpl_chan中也使用nidaqmx.constants.

with nidaqmx.Task() as task:
task.ai_channels.add_ai_thrmcpl_chan("cDaq1Mod1/ai0:2",name_to_assign_to_channel="", min_val=0.0,
                                     max_val=100.0, units=nidaqmx.constants.TemperatureUnits.DEG_C,
                                     thermocouple_type=nidaqmx.constants.ThermocoupleType.K,
                                     cjc_source=nidaqmx.constants.CJCSource.CONSTANT_USER_VALUE, cjc_val=20.0,
                                     cjc_channel="")