Due to the amount of PM's I have been getting from people asking how to connect their PID I threw these instructions together. Hopefully they will help some people out...
A guy on eBay named Tibetwalk sells a PID, SSR, TC combo for dirt cheap (I am not affiliated with this guy in any way) its a set-620 I believe and the terminal numbers in my drawing for the PID/SSR are based on it, as seen HERE.
The control should be fed from a GFCI circuit and adding a timer would also be an excellent idea.
This control uses the PID’s alarm contact to control a 2 pole NO (normally open) relay or contactor as a highlimit control, not ideal but it will kill the heater if the SSR fails closed (SSR’s often fail in the closed position leaving the heater on indefinitely). The PID must be set up correctly to open the alarm contact once the highlimit setpoint is reached. The momentary contact “reset button” is to ensure the heater stays off once the temperature drops below the highlimit setpoint. It will need resetting every time the power is turned off or if the grid power “blips”, keep that in mind if your not getting any heat! This is also a good reason to add the “heater on” indicator light.
If a line voltage highlimit is used (like the red button part of a water heater stat) the top line in the drawing can be deleted and the line voltage highlimit can replace contact R1 ahead of the heater.
Good quality, hard usage cords (SOOW cabtire) and connectors should be used for the feeds as well as a steel electrical box (D boxes are great and cheap) to house the controls. Cover up the heater terminals and any other exposed terminals with a steel box, open electrical terminals KILL people! Also be sure to ground EVERYTHING together.
It’s VERY important to use a flow (flow for an inline heater) or float switch to ensure the heater cant be powered up when not covered in oil (potential for a tank fire or worse explosion!). A cheap low power cord (like telephone wire) can be safely used to feed to the flow/float switch due to the ultra low voltage used to trigger the SSR from the PID.

If you have never wired anything up using a ladder diagram dont sweat it, they are the easiest to read. Just start at the top left and wire it wire for wire until you reach the bottom of the ladder.

Be sure to install the control away from any potential methanol fumes and dont think you can seal the box up to prevent fumes from entering it as it will only make it more hazardous.
This circuit is very similar to my current control that can be seen here;



Here are the files;
Schematic download
PID SET-620 manual download
Thanks to www.murphysmachines.com for hosting them!

All comments questions and concerns are welcomed!

Good luck!
Jon

This message has been edited. Last edited by: Jon Heron,

Excellent stuff there.

My brew-partner and I were discussing this just the other day.

I think our "next generation" reactor will be PLC controlled.

SteveM.

Jon,
If you want to email me the files, I'll be happy to host them at my site.

EDIT: 10-24-2009
The files have been uploaded and can be found here:

www.MurphysMachines.com/PID.html

This message has been edited. Last edited by: Murphy,

Thanks Murphy!
PM me your email and I will send them over...
Jon

Thought I'd chime in one more time just to point out a silly fact.

Of all the fancy stuff in that picture, IE: Digital controller, fancy buttons, fuses, disconnects, strain relief cord grips, etc etc, the most expensive part of the entire thing is the NEMA JIC box he has it all mounted in. Is that a hoffman box?
That box, with a back panel, is probably about $150 new. (I think ebay has them cheaper)

When I bought my first hoffman box, errr, 20 years ago?, I almost fell over when I found out how expensive they are.

quote:

Of all the fancy stuff in that picture, IE: Digital controller, fancy buttons, fuses, disconnects, strain relief cord grips, etc etc, the most expensive part of the entire thing is the NEMA JIC box he has it all mounted in. Is that a hoffman box?

Yep thats for sure! Hoffman box's are built about 15 minutes from where I live and they are not any cheaper here either! Try pricing out some custom made boxes from them... Makes your butt pucker!
The cords and connectors can be pricey too. I was able to salvage most of that stuff though, the box was from a surge suppressor that was taken out by lightning... Salvaging used stuff is the only way to go when your a cheap prick like me! LOL

You can get a D box with a hinged lid for a fraction of the price...
Jon

Great info Jon!Too bad your not getting royalties or a commission

quote:

Too bad your not getting royalties or a commission Big Grin

Now your talking!
Freedom 55 here I come!
Jon

quote:

Originally posted by Jon Heron:

quote:

Too bad your not getting royalties or a commission Big Grin

Now your talking!
Freedom 55 here I come!
Jon

Should we now start calling you Saint Jon????(ala St. tilly)

The files have been uploaded and can be found here:

www.MurphysMachines.com/PID.html

Hope that helps

Much appreciated Murphy!
Jon

Are you guys using the PID to control/maintain temperature during the reaction? If so, what temp do you aim for, and how long do you mix/react?

I know the answer will probably be "it depends", but I'm just looking for some guidance. Should the temp be maintained at 150 F throughout the mixing/reaction, or is there a better way?

SteveM.

With proper mixing, you aim for 128 degF for an hour. Proper mixing is very important.

Yes, the temperature should be maintained at 128 for the entire hour. That's why the PID controllers are better than the normal water heater thermostats. The PID maintains a tighter temperature control where the thermostats have more difference between the ON temp and the OFF temp.