PID controlled kettle heating element

Thread Starter

Milkgod

Joined Mar 9, 2017
21
I wanted to build a sort of hotplate using a pyramid kettle heating element controlled by a PID temperature controller. I've into some issues with the actual heating. For some reason when the heating element is connected through the ssr no matter what I do or try it will not heat up. The PID is a rex-c100 and my kettle heating element runs off 240v ac at 2500-3000W.

Maybe there is an easier way to control the temperature of a kettle heating element or am I just doing something wrong?
 

TeeKay6

Joined Apr 20, 2019
567
I wanted to build a sort of hotplate using a pyramid kettle heating element controlled by a PID temperature controller. I've into some issues with the actual heating. For some reason when the heating element is connected through the ssr no matter what I do or try it will not heat up. The PID is a rex-c100 and my kettle heating element runs off 240v ac at 2500-3000W.

Maybe there is an easier way to control the temperature of a kettle heating element or am I just doing something wrong?
@Milkgod
It is highly likely that a simple thermostatic controller (i.e. no PID, just on/off) would be entirely adequate for your purpose. PID is useful and necessary in some applications, but as the response time of the "target" becomes longer, PID is less useful except when extreme precision is needed. When the controller turns "on", it will likely be some time before the complete response is seen in whatever you are heating and long before overheating occurs, the controller will be able to turn "off."
 

LesJones

Joined Jan 8, 2017
2,444
Can you post the schematic of how you have connected all the items together. Otherwise we could be guessing forever at all the wrong ways you may have connected things together.

Les.
 

Thread Starter

Milkgod

Joined Mar 9, 2017
21
Can you post the schematic of how you have connected all the items together. Otherwise we could be guessing forever at all the wrong ways you may have connected things together.

Les.
I used this wiring diagram. I later tried using a separate power supply for the heating element with the live going first through the ssr and with the live going first through the heating element, I've tested the heating element on its own and it works fine.

I've added some pictures. The first heating element I accidentally over heated and you can see its melted itself. I have a spare that I've tested more carefully and it works just not with the PID. I think I'll try the thermostatic controller as teekay6 mentioned.
IMG_20190728_174743.jpg
IMG_20190728_174746.jpg
IMG_20190728_175741.jpg
 

Thread Starter

Milkgod

Joined Mar 9, 2017
21
@Milkgod
It is highly likely that a simple thermostatic controller (i.e. no PID, just on/off) would be entirely adequate for your purpose. PID is useful and necessary in some applications, but as the response time of the "target" becomes longer, PID is less useful except when extreme precision is needed. When the controller turns "on", it will likely be some time before the complete response is seen in whatever you are heating and long before overheating occurs, the controller will be able to turn "off."
Have you got an recommendations? I probably only need about 50 degrees c to about 150 degrees. Doesn't have to be very accurate as I'll be using a thermometer to monitor the temp.
 

LesJones

Joined Jan 8, 2017
2,444
Does the yellow "out 1" LED on the PID controller come on indicating it should be setting the heating to on ?
Your schematic looks like it is wired correctly
Les
 

Thread Starter

Milkgod

Joined Mar 9, 2017
21
Your schematic doesn't match the REX PDF at all?

View attachment 182687
Theres a wiring diagram on the side of the PID, matches up with what I posted.
Does the yellow "out 1" LED on the PID controller come on indicating it should be setting the heating to on ?
Your schematic looks like it is wired correctly
Les
Yes the LED turns on. There's 240v going across the ssr so it seems to be doing what its meant to. I haven't tested the current yet.
 

LesJones

Joined Jan 8, 2017
2,444
If there is 240 volts between terminals 1 & 2 of the SSR it is not in the ON state. Connect your meter set to the 20 volt DC range between terminals 3 & 4 of the SSR. It should be showing 12 volts. (It may be pulsing on and off.) (I have a similar PID controller to yours and the output pulses on and off when it is heating.)

Les.
 

Thread Starter

Milkgod

Joined Mar 9, 2017
21
If there is 240 volts between terminals 1 & 2 of the SSR it is not in the ON state. Connect your meter set to the 20 volt DC range between terminals 3 & 4 of the SSR. It should be showing 12 volts. (It may be pulsing on and off.) (I have a similar PID controller to yours and the output pulses on and off when it is heating.)

Les.
I get a solid 10 V maybe my PID is not configured probably.
 
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