Controlling relays using thermocouple readings

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hlaps1990
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Controlling relays using thermocouple readings

Post by hlaps1990 »

TLDR: What's the easiest way of interacting with a Phidget from inside another Phidget's event handler?

Me again, still working on the injection molding machine. The stepper motors are working great now thanks to the help I got on a previous post.

I want to regulate the temperature of the extruder using a thermocouple and four 40W cartridge heaters. I'm going to try to keep it simple for now: when the thermocouple notices a temperature change event, it checks to see if its below or above a global target temperature variable. From there, I'd like to be able to turn the heaters on or off, but I'm not sure how I can command the heaters in the temperature change handler because they were defined in a different scope. I'd prefer not to have to connect to the heaters every time I want to change them inside of the event handler. I have tried changing a global "is_heating" variable to "True", which works, but then I have to poll that value throughout the code to achieve any kind of update speed. Is there a more effective way of doing this?
jdecoux
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Re: Controlling relays using thermocouple readings

Post by jdecoux »

In Python, you can add a Phidget handle to another Phidget by assigning it as an attribute.

For details and an example, you can look at our page on Referencing Other Phidgets from Events.
hlaps1990
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Joined: Sat Jun 04, 2016 1:17 pm
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Re: Controlling relays using thermocouple readings

Post by hlaps1990 »

Awesome, that worked, thanks!
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