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Post by yyffreedom on Apr 27, 2021 5:14:39 GMT -5
Hello, I would like to use python to read the heating power which is shown in the front panel of model 335. I checked the manual and didn't find the command for the power reading.
Does anyone know the command for the power reading?
Thanks. Yifan
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Post by Lake Shore Jeff M on Apr 28, 2021 6:49:25 GMT -5
The Model 335 does not have a command that reports the power output percentage as you can see on the display.
What is shown on the display is not a measured value. The percentage displayed is a calculated value based on the 25 or 50 ohm heater resistance selection and the percentage of the maximum current that the controller is set to output. The real output percentage is different if the heater resistance is not exactly 25 or 50 ohms and if the output current is slightly different than the programmed current.
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Post by martinp on Feb 8, 2022 5:56:27 GMT -5
Does the model 325 calculate power in the same way? If I am using a heater resistor with a different value (R_actual), can I calculate the actual power (P_actual) from displayed power (P_displayed) and the stored resistor value (R_stored = 25 Ohm or 50 Ohm), like this: P_actual = P_displayed * R_actual/R_stored ?
And how would I get a value in Watts?
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Post by Lake Shore Jeff M on Feb 8, 2022 11:27:22 GMT -5
I do not believe that would give you an accurate calculation.
The power generated would be the square of the current times the resistance of the heater. If you set the output display to be current instead of power, the percentage would be based on the maximum current for the heater resistance chosen (1A for 25 ohm, .71A for 50 ohm). For example, a 20 ohm heater at 100% output on the 25 ohm setting would generate 20W. At 50% output, it would only be 5W.
Keep in mind that the heater output is not a calibrated value so its actual value may be slightly more than that the specification is so there is no way to calculate the power level with any guaranteed accuracy.
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