Lakeshore 372 temperature curve Python code issue

rk
New Member

Posts: 4

Lakeshore 372 temperature curve Python code issue Sept 12, 2024 8:23:32 GMT -5

Quote

Post by rk on Sept 12, 2024 8:23:32 GMT -5

I'm working on writing a basic Python script to retrieve temperature readings based on resistance readings from a Lakeshore 372 device.

I'm using a calibrated ROX-202A. The calibration data, named "U07241", is available in different formats: U07241.34A, U07241.234, U07241.340, U07241.cof, U07241.curve, U07241.dat, U07241.table. I've placed all the calibration files in the same folder as the Python code.

While I'm able to communicate with the Lakeshore 372 and retrieve the resistance readings (I use channel 5), the code isn't converting it into temperature as per the provided calibration curves.

from lakeshore import Model372, Model372CurveHeader


myinstrument = Model372(57600)
curve_header_25 = Model372CurveHeader("U07241", "U07241", myinstrument.CurveFormat.OHM_PER_KELVIN, 300.0,
                                      myinstrument.CurveTemperatureCoefficient.POSITIVE)


myinstrument.set_curve_header(25, curve_header_25)

data_points_list = myinstrument.get_curve(25)
sensor_1_readings = myinstrument.get_all_input_readings(5)
print(sensor_1_readings)
print(data_points_list)

I got the following output (as you can see it gives me zero temperature):

{'kelvin': 0.0, 'resistance': 2517.33, 'power': 2.51734e-09, 'quadrature': -6.02}

The table of temperature data points is all zero:

[(0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0), (0.0, 0.0)]

This is clearly the code issue, but I did not find a good source of information and troubleshooting. Thank you.

Lake Shore Ryan
Lake Shore

Posts: 94

Lakeshore 372 temperature curve Python code issue Sept 12, 2024 9:09:19 GMT -5

Quote

Post by Lake Shore Ryan on Sept 12, 2024 9:09:19 GMT -5

Did you happen to load one of those curve files onto the 372 using the Curve Handler software available for download on our website? And then configure the channel to use that curve? The instrument needs that curve loaded and assigned to the channel for it to know how to convert to temperature. The alternative is to use the polynomial equations found in the .cof and .pdf files and convert from resistance to temperature yourself. But this isn't a great option, because the instrument won't know the temperature you calculate and so it won't be able to perform closed loop control based on temperature.

Ryan Oliver
Director of Product Management, Sensors and Instruments
Lake Shore Cryotronics

Lake Shore Jeff M
Lake Shore

Posts: 327

Lakeshore 372 temperature curve Python code issue Sept 12, 2024 9:13:02 GMT -5 Lake Shore Ryan likes this

Quote

Post by Lake Shore Jeff M on Sept 12, 2024 9:13:02 GMT -5

The Model 372 has the ability to interpolate the temperature using either a straight line interpolation between adjacent curve points or with a Cubic Spline interpolation between points. This requires that you have either the curve with the .340 extension loaded for the straight line interpolation or the one with the .curve extension if you are going to use the cubic spline method.

It looks like the script is trying to read the curve points from curve location 25 so if you have not installed either of the curves into the instrument, location 25 is blank which is why you are seeing the zeros.

To load the curve into the 372, you will need a Windows PC that can run our Curve Handler software application.

If you need assistance in loading the curves into the Model 372, Please give us a call at 614-891-2243 and select option 2 for support.

rk New Member Posts: 4	Lakeshore 372 temperature curve Python code issue Sept 12, 2024 9:42:43 GMT -5 Quote Select Post Deselect Post Link to Post Back to Top Post by rk on Sept 12, 2024 9:42:43 GMT -5 Got it, thank you!

Lakeshore 372 temperature curve Python code issue

Post by rk on Sept 12, 2024 8:23:32 GMT -5

Post by Lake Shore Ryan on Sept 12, 2024 9:09:19 GMT -5

Post by Lake Shore Jeff M on Sept 12, 2024 9:13:02 GMT -5

Post by rk on Sept 12, 2024 9:42:43 GMT -5