Can't set the temperature on TC200 Thorlabs

[njrebelo]

I have written this code:

import instruments as ik

com='COM7'
baud_rate = 115200

temperature_sensor=ik.thorlabs.TC200.open_serial(com,baud_rate)
print(temperature_sensor.temperature)

temperature_sensor.temperature_set(35)

and no matter what I do the erros is always the same:
Traceback (most recent call last):
File "C:\Users\mc2\Desktop\TC200_automation.py", line 9, in
temperature_sensor.temperature_set(35)
File "C:\Users\mc2\AppData\Local\Programs\Python\Python36\lib\site-packages\instruments\thorlabs\tc200.py", line 198, in temperature_set
return float(response) * pq.degC
ValueError: could not convert string to float: ' 30.0elsius'

What can I do?

[scasagrande]

temperature_set is a property, not a function to be called

try temperature_sensor.temperature_set = 35

[trappitsch]

Looks to me like your device is sending back the string 30 Celsius when you run print(temperature_sensor.temperature).
With your code initialized as above in the image, up to line 6, could you run the following lines individually and post the output (error or not):

print(temperature_sensor.query("tset?"))
print(temperature_sensor.query("tact?"))

Also: what version of instrumentkit do you have installed?

[trappitsch]

temperature_set is a property, not a function to be called

try temperature_sensor.temperature_set = 35

That's definitely an issue as well!

@scasagrande Looks like the error shows up at the print statement though... ik has the following for the temperature read:

response = (
            self.query("tset?").replace(" C", "").replace(" F", "").replace(" K", "")
        )

The fact it complains about 30.0elsius looks like the " C" is properly stripped, but the device seems to return the full string.

[scasagrande]

@trappitsch the print statement worked, you can see it just above the traceback in the screenshot 21.9 degC

We're trying to set a property, but we're calling the getter function, which is why this then gets called, https://github.com/Galvant/InstrumentKit/blob/v0.6.0/instruments/thorlabs/tc200.py#L186, which looks like has an error that @trappitsch you did correctly identify. I wonder if there is a device setting that is changing the data format coming back from the instrument

[scasagrande]

Or maybe its just that tact returns with the short form of the units (because that did succeed), while tset? returns the long form?

[scasagrande]

Also this is likely 0.6 based on pq.degC instead of u.degC

[trappitsch]

@scasagrande Good point, I missed that return in the output. Also about the version. So maybe @njrebelo could still run the two queries I posted and try to set the temperature as @scasagrande pointed out above.

If it really sends back mixed messages (" C" for some and " Celsius"), it wouldn't be too hard a fix to implement.

[scasagrande]

@trappitsch agreed

if I get a moment this weekend I'll take a look in the manual and see what it says

[scasagrande]

So in typical Thorlabs fashion the manual is very unhelpful. It doesn't give example return values for the queries.

[trappitsch]

That sounds about right... Hopefully @njrebelo can send some typical output for tset and tact

[njrebelo]

Thank you so much for all the help, you guys were super helpful.
I its running now as I want it to.

[scasagrande]

@njrebelo could you still try this for us? print(temperature_sensor.query("tset?"))

[njrebelo]

Sorry wasn´t in the lab much this week

[scasagrande]

np @njrebelo , thank you for getting us that data!

[trappitsch]

Hmm, this is interesting and weird. It really looks like tact? sends back C for the unit and tset? Celsius. I guess we can add a replace routine that acts on Celsius before acting on C, just to be on the safe side in case this is a settings thing...

[scasagrande]

Fixed in #333