Pilot Light Placement

[stratslinger]

I'm planning out a control panel, based in part on the design at theelectricbrewery.com and in part on a couple of PJ's designs - and one thought just occurred to me with regards to placement of the pilot lights for each element.

My current plan calls for the pilot lights to be wired in series to the element outlets themselves, just as in theelectricbrewery's design. This would work pretty well for the HLT element, as it would tell me any time the element is firing. Useful info, at least. But on the BK, I intend to use the duty cycle feature on the Auber PID - running the element at 100% until I reach a boil, then throttling back to whatever can reasonably maintain the boil. At that point, would the LED just flicker for the duration of the boil? Would it be more useful to put the BK LED in series with the power switch for that circuit?

 

[FastTalker]

You do not want to put the pilot light in series with the element. You'll need to put it in parallel with the control signal that is firing, presumably, your SSR for the heating element.

 

[stratslinger]

OK - I'm definitely getting series and parallel mixed up here - but I'm actually going off of Kal's design at theelectricbrewery.com, where he has 240v pilot lights hanging off the two 120v legs of each element outlet (I see what you mean, this does appear to be parallel, not in series). But it's still in parallel to the element, not the control signal, so I guess my question still stands, based on Kal's design.

 

[jeffmeh]

Trace the 2 hots from the element to the next terminations. Run a hot from each of those terminations to your 240v led. Parallel achieved.

 

[stratslinger]

That's exactly what Kal's design does, jeffmeh - so I misspoke when I said it was in series.

So the question, put correctly: would a pilot light, wired in parallel with the HLT element, tend to flicker on and off throughout the boil with a PID set to a duty cycle of less than 100%?

 

[FastTalker]

It will flash at whatever rate the element it being cycled on and off.

 

[stratslinger]

And does anyone know roughly how rapid that is on an Auber PID?

I get that it'll flash as often as the PID does - I'm trying to figure out if that's going to be an annoying flicker that I want to avoid, or "on 7 seconds, off 3 seconds, repeat." Hence the question "would the LED just flicker for the duration of the boil?"

 

[FastTalker]

I'm pretty sure this is configurable for Auber PIDs. It probably depends on the actual model you have. It will be on the order of seconds. Check the "cycle time" or "cycle rate" parameter.

 

[kal]

And does anyone know roughly how rapid that is on an Auber PID?

I get that it'll flash as often as the PID does - I'm trying to figure out if that's going to be an annoying flicker that I want to avoid, or "on 7 seconds, off 3 seconds, repeat." Hence the question "would the LED just flicker for the duration of the boil?"

See the video at the bottom of this page for this flashing in action:

http://www.theelectricbrewery.com/brew-day-step-by-step?page=9

About 2 min 26 sec into the video you'll see the boil PID going at 80% duty cycle flashing on/off.

The cycle is 2 seconds, so if set to 80% duty cycle it'll be on for 2*0.8 = 1.6 seconds and then off for 2*0.2 = 0.4 seconds.

Part of the reason for the light is safety so that you know if the element is receiving power since it's hardwired across (in parallel) to the element. So if the light is on, the element output is live. Nothing else made sense to me (ie: wiring a different way doesn't give you a true indicator of what's going on. Wiring it in parallel to the power switch does not tell you when the element is one).

Good luck!

Kal

 

[stratslinger]

Figures I should've watched the video all along... Instead I spent all my time digesting the pretty diagrams and their detailed descriptions. Thanks Kal!