1 Topic by ajp

  • ajp
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  • Registered: 2017-06-12
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Topic: Questions about the Sestos PID

Hi all!

I just recently finished assembling my Filastruder 2.1 and I had a few questions about the operation of the PID. I was comparing the wiring diagram and the terminal arrangement in the PID manual, and noticed that the positive of the power supply is wired to pins 8 and 9, but in the manual, pins 9 and 10 are designated as power. Also, the heater is placed between pins 7 and 10, while according to the manual, the heater should be placed somewhere in pins 6-8. I am interested in controls and would really just like a more in0depth explanation of the PID wiring.

Thanks in advance!

2 Reply by elmoret

  • elmoret
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  • Registered: 2012-10-11
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Re: Questions about the Sestos PID

Pins 9 and 10 are indeed power. Pin 9 is positive, Pin 10 is negative.

Pins 6, 7, and 8 are terminals of a relay. A relay is a switch that completes one half of a circuit. The heater needs positive and negative to function. The heater is connected directly to negative (pin 10), and the relay switches the positive side of the heater.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

3 Reply by ajp

  • ajp
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Re: Questions about the Sestos PID

Let me make sure I'm understanding this correctly. If the thermocouple reads below the target temperature, the PID will toggle the relay, providing power to pin 7 through the relay from pin 8. When the thermocouple reads over the set temp, the PID will toggle the relay so that pin 7 is isolated from the power on pin 8.

4 Reply by elmoret

  • elmoret
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Re: Questions about the Sestos PID

Short answer: Yes.

Long answer: PID can call for heat while measured temperatures is above the desired, if for instance the measured temperature is falling. This is the "D" portion of PID. There are three gains:

P: proportional to the difference between desired and actual
I: integral of the difference between the desired and actual (this is used to compensate for slight differences over time)
D: derivative of the difference between desired and actual (is the error getting worse or better?)

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend