PID controller questions

[yondering]

Just got done reading this thread http://www.castboolits.gunloads.com/showthread.php?t=67637 by lwknight, and have a few questions but didn't want to hijack his thread.

Looking at auberins.com, they have 3 different PID controllers that look like they should work (to my inexperienced eyes).

1/16 DIN PID Temperature Controller (Relay Output) SYL-2342 (http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=1)
This one appears to be what lwknight used. It says it controls up to 10 amps with an internal relay.

What is the difference, for controlling a Lee 20lb pot, between this one:
Universal 1/16 DIN PID Temperature Controller SYL-2362 (http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=106)
and this one:
1/16 DIN PID Temperature Controller (SSR control output) SYL-2352
(http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=3)?

It appears that the first one can be configured to control either a contactor relay or SSR, but it's cheaper. Am I missing something?

I figured this SSR looks like the way to go, is that right?
25A SSR (http://www.auberins.com/index.php?main_page=product_info&cPath=2&products_id=9)
Do I need a heat sink for it, to handle the 6 amps of the Lee pot, or are some vents in the box sufficient? I do have a small 12v cpu fan, but not sure what I'd need in the way of a transformer to use it.

I'm no electrical engineer, as you can tell.

I haven't looked at what I'll need for a TC yet.
Thanks for any suggestions.

[Casting Timmy]

Some people prefer the solid state relays because they don't have the points to wear out. They will both preform the same, but the SSR controller will need the SSR to go with it. At my work we use controllers and mainly have the points control another relay for load and shorting problems.

One thing I think would be interesting to know about these controllers is how they come set up. Most controllers can have the dead band and other features adjusted in them to hold tighter temperature ranges. The down fall is more switching of the controller. I know that some of our controllers at work have been there for years putting in 40 hours a week with the points contacts and haven't failed yet. They are monitored once a year for ensuring they work correctly, so I wouldn't worry about going with the regular controller. I would recommend a couple of fuses in there for either controller you pick though.

[lwknight]

I will look it up and expand on this matter in the morning. In my experience, you need an external relay of some kind. My internal 10 amp SSR got stinking hot and then I realized that I had to get an external contact. Makes no reeal difference if its a SSR or old fashioned contactor. Both draw minimal power and will not overheat the PID's internal switch.

[theperfessor]

I'm in the process of building a dual PID controller for my 20 lb Lyman pot and a hotplate for mold preheating. I ordered the SYL-2352 model as well as 2 of the 25A SSRs. Also ordered two thermocouples, one is a 6" (WRNK-171) probe type (for lead pot) and the other has a 1/4-20 x 1/2" long hex bolt mounting (TC-K6). I plan to put that into drilled and tapped hole in several test molds. This would be sensor used to cycle hot plate to preheat mold.

Right now I'm designing enclosure. I'll be glad to make those drawings available. The data sheet says that you don't need to heatsink the 25A SSRs below 10 A current so you're probably OK. My Lyman pot says it's an 800W 10A unit so I'm right on the edge. I'm planning on making the enclosure out of some scrap 1/4 aluminum plate so that will provide some heatsinking right there. I figure you can always get a cheap fan to blow on the box if you have to, so I think you're right about putting in some vents.

I think I'll do a websearch to see if there are any cheap 110V AC enclosure fans out there so that you wouldn't have to put in a transformer. Does anybody know the electrical requirements for the cooling fans in a PC?

[Frozone]

I think I'll do a websearch to see if there are any cheap 110V AC enclosure fans out there so that you wouldn't have to put in a transformer. Does anybody know the electrical requirements for the cooling fans in a PC?

PCs use a 12V fan but you can get a $12 110Vac fan at www.Jameco.com

If you use an AL case just bolt the SSR to the case using Heatsink Grease, then on the outside add a Sink.
Here (http://cgi.ebay.com/Aluminum-Heat-Sink-3-3-4-x-2-3-4-x-1_W0QQitemZ380184436416QQcmdZViewItemQQptZLH_Defau ltDomain_0?hash=item5884c21ec0)is a good example on EBay right now (14hr to go).
Here (http://cgi.ebay.com/Aluminum-Large-High-Fin-Density-Heatsink-MOSFET-8x6-7-8_W0QQitemZ150395094855QQcmdZViewItemQQptZLH_Defau ltDomain_0?hash=item23043f0747) is a second choice.
If you use a steel case just cut an opening that will fit the SSR and mount to the Sink through the wall.

[Storydude]

I"d suggest allelectronics.com for the Fan.

[Matt3357]

I used this box:

http://www.lowes.com/lowes/lkn?action=productDetail&productId=10030-223-E987R-CAR&lpage=none

I cut holes with a drill bit and coping saw. Could easily use a dremel. Super cheap and durable. Just add vents and yer golden. BTW the mounting tabs bolt on and are not assembled.

Matt

[The10mmKid]

The controller with the dual outputs will be 'assigned' an output when you configure it.

I.E.
Output #1, which may be SSR is "Alarm #1"
Output #2, which may be the relay will be assigned "Heat Output"

Pretty common setup nowa'days.

No fan needed, just heatsink compound and tightly mounted to your metal housing.

If you do plan on fusing this, it would pay to buy the Fast-Action fuses. The SSR will short before a Time-Delay fuse will open up.

Try to use at least 14ga wire. I'd use the inside wire from an old extension cord. Very flexible and easy to solder or crimp on a connector.

'da Kid

[The10mmKid]

I used this box:

http://www.lowes.com/lowes/lkn?action=productDetail&productId=10030-223-E987R-CAR&lpage=none

I cut holes with a drill bit and coping saw. Could easily use a dremel. Super cheap and durable. Just add vents and yer golden. BTW the mounting tabs bolt on and are not assembled.

Matt

Matt,
What, if any, HD output did you use?

'da Kid

[Matt3357]

Please clarify on what an HD output is. I have built the thing but have yet to program the controller. The farthest I have gotten is to read the instructions about a week ago with no time since to look at it.

Matt

[lwknight]

Just looking at the controllers wiring diagrams and unclear descriptions, it looks like the SYL-2342 out put is simply a switch and nothing more and will not operate an external SSR without a power supply. I did use a 24v transformer to power my contactor.

And It looks like the SYL-2352 can only be operated with an external SSR and powers the SSR. Meaning that this output will not operate a seperately powered contactor or SSR

The SYL-2362 is unclear but appears to power the alarm outputs.

[blikseme300]

Here is the list of parts, including part numbers, I bought from Auber Instruments to build my PID setup:

1 x Universal 1/16 DIN PID Temperature Controller (SYL-2362) = $41.95
1 x Panel mount connector for K thermocouple (TCCON) = $4.90
1 x K type high temperature thermocouple for heat treatment (WRNK-191) = $19.62
1 x 40 A SSR (RS1A40D40) = $19.00
1 x Heat Sink for 40A SSR (HS40) = $18.50
1 x Box for 1/16 DIN controller (Pbox16) = $28.67

To see a pic of my PID setup and melting pot go here:

http://bliksemseplek.com/boolits.html

I have the circuit diagram I used scanned to a PDF so if anybody is interested contact me at bliksem at bliksemseplek dot com.

Bliksem

[lwknight]

Does your controller supply voltage to the SSR or the SSR have its own low voltage power?
What is the voltage to oporate the SSR?
I'm thinking that it would be more convenient to not need an external transformer. Your set is nicer than mine and also more costly.

[theperfessor]

According to the spec sheet, the 2352 supplies the proper DC voltage to power SSR directly, no need for external power supply. You do need external DC supply for alarm circuits but since Hi/Lo alarms on front of PID unit are there I wasn't planning on using external alarms.

Of course you need to supply 110VAC to output of SSR. I planned to use a regular 110VAC outlet and just plug lead pot and hotplate into regular plug in sockets. Fuses are good too.

I selected 2352 unit because you don't need a lot of external stuff, there are only six wires to hook up - two for SSR output, two to 110VAC power, and two for thermocouple input.

Seemed simplest way to do things to me but others of course have different and equally good ideas.

[theperfessor]

Here is scan of PID documentation received with 2352 unit. Connections are on back of PID unit and are clearly labeled and numbered.

[The10mmKid]

Please clarify on what an HD output is. I have built the thing but have yet to program the controller. The farthest I have gotten is to read the instructions about a week ago with no time since to look at it.

Matt

HD = Heavy Duty

That would imply a contactor or SSR used to handle the higher current of the pot (verses the close-to-max relay inside the controller).

The Perfessor appears to have all the right data in front of him. I'm just reading the Auber PDF for the controller online.

SSR's require minimal voltages to switch on/off. Some even down to 3VDC. The Perfessors controller choice provides that needed SSR voltage.

'da Kid

[Matt3357]

I am using the 25 amp SSR from Auber. I was working the little bit I was playing with it.

Matt

[Frozone]

Looking at auberins.com, they have 3 different PID controllers that look like they should work (to my inexperienced eyes).

The '42 uses a N.O. (Normally Open) relay for output and requires an external power supply for the circuit. It is rather current limited and requires an external relay to switch heavy loads. You'd need a transformer to use anything other than line power.

The '52 has a SSR output and provides 40ma at 12v to run the SSR without any external circuity.

The '62 has both types of outputs, But you must program it to the configuration you need.

The '52 is the best choice for SSR use. I see no reason for using the '62, It just adds complexity.

Add a stepdown transformer ( they are very inexpensive but do add heat to the internals) and the '42 is perfect. You can run a lowvoltage circuit for a mechanical relay as well as ( with the addition of a simple diode/capacitor) a LED warning light system. With the '52 you need to use line power for the warning circuit to keep things simple - that means lamps or neons = expensive.

Additionally, if you build your own melter, you can use 2 heaters and use the UnderTemp alarm to control the second heater to more quickly get up to temp. Than get fine control with only one heater.

[Texasflyboy]

To see a pic of my PID setup and melting pot go here:

http://bliksemseplek.com/boolits.html


:holysheep
:holysheep

Nice Setup!

Waow!

[theperfessor]

The two thermocouples I got from Auber have spade lug ends. Rather than use a plug in I was just planning to use a two-screw terminal strip on exterior of box. I don't want to have to get a new jack if I change TCs later. It's low voltage so outside mount should be safe. Anybody see any problems with not using a jack?

[Frozone]

Anybody see any problems with not using a jack?

Just be sure to continue from the terminal strip into the box with the same ThermoCouple wire, you don't want to use normal wire.

Oh, I'm sure you know this but, be sure to observe the wire polarity across the terminal block. red stripe to red stripe ect.

You may notice the spade connectors on the wire are Al not TC material.
Why this works: A K type TC is just 2 dissimilar metals and you read the dielectric voltage generated.

When you put the terminal strip in the circuit you add a junction that adds (or subtracts) from the voltage at the main junction.
But the opposite connection Leaving the strip cancels the voltage of the input connection leaving only the original signal.

http://en.wikipedia.org/wiki/Thermocouple#Law_of_homogeneous_material
See "Law of intermediate materials"

Hope this helps.

[Matt3357]

Yeah, since the terminals you will be using are going to be made of some sort of steel or copper and not the same material as the thermocouple, all you will read on your PID is the Ambient air temp at the terminals. Check out the thermocouple plug and mount on the last page of the Auber thermocouples. It explains everything I just said. Its not too expensive when you compare it to the cost of the thermocouples. Hope this helps.

Thanks,
Matt

[theperfessor]

I'll either get the TC jack as suggested or just drill holes in box and hook directly to PID unit. Forgot basic principle of how TC works, appreciate reminder.

[lwknight]

Additionally, if you build your own melter, you can use 2 heaters and use the UnderTemp alarm to control the second heater to more quickly get up to temp. Than get fine control with only one heater.

Frozone, you are making me spend more money. I never even thought about using the alarm relay for a booster heater.
Awesome idea!!!!

[theperfessor]

I'd like to thank Frozone for his helpful information sent to me via pm. It is much appreciated!