Sciencemadness Discussion Board

wiring PID controlled heating tape from 230V to 120V

razor0109 - 8-8-2018 at 11:36

I live in Europe, and having trouble figuring out how not to overpower my heating tape, which is rated for 120V - 480W.

I purchased an ITC-100 PID controller with an SSR-40 DA, and was wondering how to wire everything without the need for an adapter (230/120 V) with high enough output power - these adapters are quite expensive.

I checked the documentation for the PID controller, and found no info on how I could limit it's output to 120V.

Any suggestion/explanation would be greatly appreciated!

battoussai114 - 8-8-2018 at 11:43

You won't be able to drop the voltage down with the controller. These things are made to switch the power on and off and stepping the AC voltage down would probably require a transformer.
You could theoretically use the controller to reduce the duty cycle by half and it would be sort of like having it running at 120V, but I feel peaks of a voltage about twice the rated one will not be very good for the heating element in the long run.

JJay - 8-8-2018 at 11:51

I use a triac dimmer in-line with my PID controller to cut the amperage. You could get something like that to work with your setup, but it's a good idea to check the resistance on the heat tape and do the math yourself.

Oh and I am personally not concerned about the voltage peaks on a resistive heating element.




[Edited on 8-8-2018 by JJay]

razor0109 - 8-8-2018 at 11:53

Thanks for your advice!

I was thinking that a transformer will be necessary, and since you've confirmed, I found a converter unit fitting my power needs for relatively cheap.

DavidJR - 8-8-2018 at 11:57

Yeah, resistive heating elements don't give a crap about peak voltage or anything like that. Any possible damage would be from thermal effects, which are slow, so really all you need to worry about is average power [assuming you average over a sensible time window that isn't too long].

andy1988 - 8-8-2018 at 16:03

Quote: Originally posted by razor0109  
having trouble figuring out how not to overpower my heating tape


If it turns white hot and smells like burnt stuff? :D

Disclaimer: I am an amateur, not an expert. I apologize if I say anything wrong/misleading, please correct me if so.

I don't exactly know if this is applicable to your use case but you may find the following interesting. EDIT: Actually your use case does sound like AC now that I read the rest of the responses. I guess you could pull a part out of an electric stove and use that? Look at how those are designed. EDIT2: Hmmm maybe not. Good luck, sorry I don't know how to duty cycle AC... also try not emit crazy EMI with it.

If you have a suitable benchtop DC/(AC?) power supply and IR camera (or other suitable temperature measurement device), you could get fancy like this.

Your independent variables are: heating tape length (between where leads are clamped on) and DC voltage (rms voltage if AC?). Adjust those and see the dependent variables: current draw and temperature. If the tape is drawing more current than the power supply can handle, then... the DC power supply will probably activate the current limit "failsafe" mode (safety feature, make sure the power supply has it) and drop the current to 0. I guess you could make do with a fuse as well/alternative (as my tabletop AC-powered "George Forman" electric grill has).

Now, benchtop testing is a bit different than real-world. You may have insulation in its final destination (thank goodness for that PID controller). I'd suggest throwing in one or two thermal switches (which open the circuit when specific temperature reached) as a failsafe, in case the PID somehow fails. NC in the partname on the thermal switches means "normal closed", as in when the specified temperature is reached, it mechanically opens the circuit.

Anyways, that is all I know really on the subject... I have a bunch of heating tape but haven't gotten around to using it yet beyond playing with it. Actually I did make a heater for my chickens with it :D I ran some tape through some pvc-ish pipe. They sat on it in the depths of winter and melted/distorted the plastic tubing (fluffy chicken insulators) :o So I took it away, they didn't need it anyway.

[Edited on 9-8-2018 by andy1988]

Sidmadra - 8-8-2018 at 16:42

Quote: Originally posted by DavidJR  
Yeah, resistive heating elements don't give a crap about peak voltage or anything like that. Any possible damage would be from thermal effects, which are slow, so really all you need to worry about is average power [assuming you average over a sensible time window that isn't too long].



^^^ This was what I was going to say.

The only real consequence of hooking a heating element up to a 230x that is intended for 120v is that it will heat approximately 4x faster, drawing approximately 4x the amount of power. That's pretty much all you need to take into consideration here. As others have said a variac would do just fine for regulating this.

TheMrbunGee - 8-8-2018 at 20:45

I use this for powering my heating mantle (I bought just the heating part of the mantle.) (spoiler: not actually made to handle 10 kW) And you can get less powerful units for cheaper.

I just hooked it up and turned it on at lowest setting, gradually turning on the power. In your case you just measure the voltage as you go!

Sulaiman - 8-8-2018 at 22:51

It is not difficult to spot an engineer ...
you use a 10 kW dimmer for your mantle :o
and for my nominally 250W diy mantle (actually 384W) I use a 4kW dimmer :P
... and keep one spare :D


One approach to the 110:230 V heating tape problem is to use two similar power 110V tapes in series,
and use a triac dimmer / phase angle controller for fine control.

razor0109 - 9-8-2018 at 11:46

Quote: Originally posted by Sidmadra  
Quote: Originally posted by DavidJR  
Yeah, resistive heating elements don't give a crap about peak voltage or anything like that. Any possible damage would be from thermal effects, which are slow, so really all you need to worry about is average power [assuming you average over a sensible time window that isn't too long].



^^^ This was what I was going to say.

The only real consequence of hooking a heating element up to a 230x that is intended for 120v is that it will heat approximately 4x faster, drawing approximately 4x the amount of power. That's pretty much all you need to take into consideration here. As others have said a variac would do just fine for regulating this.


So basically I could get almost 2000W of power out from the tape without considerable damage to the element?

As far as "sensible time window" goes, I don't plan to use the tapes for more than a few (<5) hours at a time. Unless, for instance I want to distill sulfuric acid, I doubt that I will heat the element to maximum power all the time.

razor0109 - 9-8-2018 at 11:51

Quote: Originally posted by TheMrbunGee  
I use this for powering my heating mantle (I bought just the heating part of the mantle.) (spoiler: not actually made to handle 10 kW) And you can get less powerful units for cheaper.

I just hooked it up and turned it on at lowest setting, gradually turning on the power. In your case you just measure the voltage as you go!


Considering the dimmer alternative, I found this dimmer adapter which is available at the local hardware store:

https://www.conrad.com/ce/en/product/614500/GAO-0784-Dimmer-...

Might go for the that voltage regulator you recommended, if the seller is willing to ship it fast :)

TheMrbunGee - 9-8-2018 at 13:38

Quote: Originally posted by razor0109  
Quote: Originally posted by TheMrbunGee  
I use this for powering my heating mantle (I bought just the heating part of the mantle.) (spoiler: not actually made to handle 10 kW) And you can get less powerful units for cheaper.

I just hooked it up and turned it on at lowest setting, gradually turning on the power. In your case you just measure the voltage as you go!


Considering the dimmer alternative, I found this dimmer adapter which is available at the local hardware store:

https://www.conrad.com/ce/en/product/614500/GAO-0784-Dimmer-...

Might go for the that voltage regulator you recommended, if the seller is willing to ship it fast :)


I don't think 500W will be enough! At least for 5 hour distillation.

Fulmen - 9-8-2018 at 14:22

Quote: Originally posted by razor0109  

So basically I could get almost 2000W of power out from the tape without considerable damage to the element?


No. Hooking it to directly to 220V would produce 2kW which would quickly heat the tape until failure. But pulsing 220V @25% duty cycle will reduce the average power to 500W. And as long as the cycle duration isn't too long it will work just fine.

WGTR - 9-8-2018 at 19:20

If you can find 120V lamps, then you can add them up in parallel until they equal 500W, and then put them in series with the heating element. A 120V 500W halogen work lamp would be ideal...but it's gonna be bright.

razor0109 - 10-8-2018 at 03:33

The PID has a built-in switching power supply.

Will this not interfere with the dimmer?

JJay - 10-8-2018 at 03:40

What do you mean by "switching power supply?"

My PID controller connects directly to a large solid-state relay. It works fine with a dimmer.

I would not connect the PID controller's power supply to the dimmer. I don't know about yours, but mine is designed to work with a range of voltages. Even so, connecting the dimmer to the power supply seems likely to cause problems. Instead, connect the regulated current to a dimmer.

razor0109 - 10-8-2018 at 03:52

Quote: Originally posted by JJay  
What do you mean by "switching power supply?"

My PID controller connects directly to a large solid-state relay. It works fine with a dimmer.

I would not connect the PID controller's power supply to the dimmer. I don't know about yours, but mine is designed to work with a range of voltages. Even so, connecting the dimmer to the power supply seems likely to cause problems. Instead, connect the regulated current to a dimmer.


Thank for clearing up my confusion.

I am still not sure how to wire every component together, but this is the idea so far:

- wire the dimmer to the input of SSR
- connect the PID to the output of SSR
- connect the heater element to the PID
- ensure common ground connection with the PID and the dimmer

this is the dimmer I will use:

https://www.conrad.com/ce/en/product/614500/GAO-0784-Dimmer-...

streety - 10-8-2018 at 04:01

The PID should be connected to the input of the SSR and the dimmer and heater element connected to the load side.

DavidJR - 10-8-2018 at 08:35

Quote: Originally posted by razor0109  

So basically I could get almost 2000W of power out from the tape without considerable damage to the element?

As far as "sensible time window" goes, I don't plan to use the tapes for more than a few (<5) hours at a time. Unless, for instance I want to distill sulfuric acid, I doubt that I will heat the element to maximum power all the time.


Instantaneous power, yes, but not average.

When I was talking about averaging over a sensible time window I was really referring to PWM aka on/off control - ie using a controller that cycles between on and off, the ratio of the time spent in the on and off state (called the duty cycle) determining the average value. Many of the cheap PID controller modules operate in this way.

If the period of the cycling is up to a few seconds, then the thermal effects will average out the temperature pretty nicely. However if on the order of several minutes or longer, then the temperatures reached during the on period might be enough to cause damage to the element (even though the average power may be the same when you average over a whole number of cycles].

razor0109 - 11-8-2018 at 12:25

Quote: Originally posted by TheMrbunGee  
I use this for powering my heating mantle (I bought just the heating part of the mantle.) (spoiler: not actually made to handle 10 kW) And you can get less powerful units for cheaper.

I just hooked it up and turned it on at lowest setting, gradually turning on the power. In your case you just measure the voltage as you go!


So how come you use a 10kw regulator? One with 500W output would not work?

TheMrbunGee - 12-8-2018 at 00:39

Quote: Originally posted by razor0109  
Quote: Originally posted by TheMrbunGee  
I use this for powering my heating mantle (I bought just the heating part of the mantle.) (spoiler: not actually made to handle 10 kW) And you can get less powerful units for cheaper.

I just hooked it up and turned it on at lowest setting, gradually turning on the power. In your case you just measure the voltage as you go!


So how come you use a 10kw regulator? One with 500W output would not work?


1. I bought it thinking of other applications
2. I don't trust Chinese hardware specifications, i don't think it can really handle 10kW
3. If you use something at maximum power - it will fail sooner.
4. It costs 11 bucks.
5. 4kW module costs 7 bucks
6. Using it with my mantle - it does not even warm up. If you use 500W module on 500W device - it will heat up.

razor0109 - 12-8-2018 at 06:22

Quote: Originally posted by Fulmen  
Quote: Originally posted by razor0109  

So basically I could get almost 2000W of power out from the tape without considerable damage to the element?


No. Hooking it to directly to 220V would produce 2kW which would quickly heat the tape until failure. But pulsing 220V @25% duty cycle will reduce the average power to 500W. And as long as the cycle duration isn't too long it will work just fine.


I have two options on the PID for controlling the output cycle:

output lower limit (Opl)
output upper limit (Oph)

Provided my math is right, I set the controller to 25% output limit, and the tape started smoking very quickly.

I tried to play around with these two settings, but the tape overheated each time. While set to 100 C, the SSR blinked the least amount while the upper limit was set to 85%, and the lower limit was set to 0%.

The dimmer I bought doesn't work at all. No matter where the slider is, while the tape is connected, only about 20-40VAC can be juiced out. If it's connected to the load side of the SSR, or directly to the outlet, there is no difference in the lacking dimming effect. Maybe the wiring is wrong. Does anyone has experience with Inkbird ITC-100 PID setup?

[Edited on 12-8-2018 by razor0109]

wg48 - 12-8-2018 at 10:27

Razor:

First double check you wiring. There is probably a wiring diagram in the set up manual for the PID there is in this one http://pmod79883.pic31.websiteonline.cn/upload/ITC-100_Manua... The dimmer should be connected in series with the Live connection to the heater

Then I suggest you replace your heater with a 230V tungsten filament light bulb, say a table lamp. That should help you trouble shoot your problem with out burning out your heater. You should be able to check the dimmer works by passing the SSR by shorting it out the two mains terminals and then that SSR turns on and off via the control from the PID. You should also be able to check you have set the PID up correctly particularly if you tape the temperature sensor to the bulb.

I forgot to say there is a chance the SSR in series with a dimmer will not work correctly depending on the type of SSR and dimmer. The above tests should tell you if that’s a problem or not.




[Edited on 12-8-2018 by wg48]

razor0109 - 13-8-2018 at 06:57

Quote: Originally posted by wg48  
Razor:

First double check you wiring. There is probably a wiring diagram in the set up manual for the PID there is in this one http://pmod79883.pic31.websiteonline.cn/upload/ITC-100_Manua... The dimmer should be connected in series with the Live connection to the heater

Then I suggest you replace your heater with a 230V tungsten filament light bulb, say a table lamp. That should help you trouble shoot your problem with out burning out your heater. You should be able to check the dimmer works by passing the SSR by shorting it out the two mains terminals and then that SSR turns on and off via the control from the PID. You should also be able to check you have set the PID up correctly particularly if you tape the temperature sensor to the bulb.

I forgot to say there is a chance the SSR in series with a dimmer will not work correctly depending on the type of SSR and dimmer. The above tests should tell you if that’s a problem or not.
[Edited on 12-8-2018 by wg48]


Hi,

I attached the wiring diagram.

I wired the dimmer to terminal 10 and terminal 2 on the SSR.

The lamp I hooked up the same way (without the dimmer) worked without a problem - the bulb synchronized with the regulated output signal.

I'm going to purchase a more powerful bulb and try it through SSR-Dimmer-Bulb configuration.


[Edited on 13-8-2018 by razor0109]

ITC_100_wiring.PNG - 88kB

wg48 - 13-8-2018 at 12:54

Here is what the wiring diagram should be. As I thought I said the dimmer is in series with SSR. The diagram assumes the pid is powered from the 230V mains and the dimmer is a two terminal type. I do not know if the connection numbers for the SSR and PID are correct so check them.The switch and fuse are not essential.

ssr&dimmer.jpg - 24kB

WGTR - 13-8-2018 at 20:04

Before you buy anything else, let's run through what your settings are. I don't see why you are using a dimmer. It shouldn't be necessary at all.

I'm looking at the ITC-100 manual. What is your setting for the CtL parameter? Since you are overdriving your heating element, this setting should be very low, 0.5-1.0 seconds. This limits your "ON" time to a value that hopefully won't smoke your heating element. It's possible that your heating element has a very low thermal mass, and the default 4 second period is just too much for it to handle. This parameter can be set as high as 120 seconds, but this is only useful when driving mechanical relays, as they have a limited switching life. Solid state relays have no such limitation. The very lowest setting of 0.5 seconds can limit your attainable resolution (assuming you have 50-60Hz power), but we are just trying to get it working right now.

Set Oph to "25", and Opl to "0". oP1 should be "0".

Try adjusting your temperature setting below room temperature with the thermocouple attached. The output should be completely "OFF". If it turns "ON", something is backwards.

[Edited on 8-14-2018 by WGTR]

razor0109 - 14-8-2018 at 12:14

Quote: Originally posted by razor0109  
Quote: Originally posted by wg48  
Razor:

First double check you wiring. There is probably a wiring diagram in the set up manual for the PID there is in this one http://pmod79883.pic31.websiteonline.cn/upload/ITC-100_Manua... The dimmer should be connected in series with the Live connection to the heater

Then I suggest you replace your heater with a 230V tungsten filament light bulb, say a table lamp. That should help you trouble shoot your problem with out burning out your heater. You should be able to check the dimmer works by passing the SSR by shorting it out the two mains terminals and then that SSR turns on and off via the control from the PID. You should also be able to check you have set the PID up correctly particularly if you tape the temperature sensor to the bulb.

I forgot to say there is a chance the SSR in series with a dimmer will not work correctly depending on the type of SSR and dimmer. The above tests should tell you if that’s a problem or not.
[Edited on 12-8-2018 by wg48]


Hi,

I attached the wiring diagram.

I wired the dimmer to terminal 10 and terminal 2 on the SSR.

The lamp I hooked up the same way (without the dimmer) worked without a problem - the bulb synchronized with the regulated output signal.

I'm going to purchase a more powerful bulb and try it through SSR-Dimmer-Bulb configuration.


[Edited on 13-8-2018 by razor0109]


What exactly do you mean by shorting out the two main terminals? Which terminals are those?

wg48 - 14-8-2018 at 22:33

Bypass the power terminals of the SSR by adding the link shown in green in the diagram below and replace the heater with a tungsten filament light bulb as visual test indicator.

With that link connected the SSR is bypassed and therefore only the dimmer should be controlling the brightness of the bulb.

If that works OK set the dimmer so the bulb is dim (25% of full power, probably just red glow of the filament). If you have a rms reading meter you could set the voltage to 110V/120V if you don't know if the meter reads rms or not set it to 90V (estimated). Perhaps mark the position on the control knob on the dimmer so you will now what position you must have it set to when you try with the heater later.

Now remove the link to allow the dimmer and the SSR to control the power to the bulb (because they are connected in series) Check if the PID can now control the power to the bulb via the SSR.

If you can not control the brightness of the bulb with the SSR bypassed your wiring is incorrect and/or the dimmer is faulty.

short copy.jpg - 24kB

JJay - 15-8-2018 at 00:02

I wired a standard outlet to my PID controller. I also have a dimmer wired with a power cord and a standard outlet. I plug heating elements into the dimmer's outlet. I usually just use the dimmer device as a standalone controller for refluxes and distillations and whatnot, but I add the PID controller when precise temperature control is required so that I don't have to monitor the apparatus constantly.

razor0109 - 15-8-2018 at 05:04

Quote: Originally posted by JJay  
I wired a standard outlet to my PID controller. I also have a dimmer wired with a power cord and a standard outlet. I plug heating elements into the dimmer's outlet. I usually just use the dimmer device as a standalone controller for refluxes and distillations and whatnot, but I add the PID controller when precise temperature control is required so that I don't have to monitor the apparatus constantly.


What is strange is that hooking the heater tape directly into the dimmer's socket doesn't work. I measure about 40 Volts reaching the tape no matter which setting the dimmer was on. I could not test the dimmer with a powerful enough light bulb yet (above 20W) though. In any case, I'll try all the above written ideas and see what happens!

razor0109 - 15-8-2018 at 12:43

Quote: Originally posted by WGTR  
Before you buy anything else, let's run through what your settings are. I don't see why you are using a dimmer. It shouldn't be necessary at all.

I'm looking at the ITC-100 manual. What is your setting for the CtL parameter? Since you are overdriving your heating element, this setting should be very low, 0.5-1.0 seconds. This limits your "ON" time to a value that hopefully won't smoke your heating element. It's possible that your heating element has a very low thermal mass, and the default 4 second period is just too much for it to handle. This parameter can be set as high as 120 seconds, but this is only useful when driving mechanical relays, as they have a limited switching life. Solid state relays have no such limitation. The very lowest setting of 0.5 seconds can limit your attainable resolution (assuming you have 50-60Hz power), but we are just trying to get it working right now.

Set Oph to "25", and Opl to "0". oP1 should be "0".

Try adjusting your temperature setting below room temperature with the thermocouple attached. The output should be completely "OFF". If it turns "ON", something is backwards.

[Edited on 8-14-2018 by WGTR]


I did as you advised and figured out that my wiring was completely wrong. As I adjusted the temperature below room temp., the output turned on regardless. I rewired (without the dimmer) according to the diagram I posted earlier (now the wiring cannot be a problem), adjusted all the settings, but unfortunately still overpowered the heater.

WGTR - 15-8-2018 at 12:48

Can you post a picture of the heater, or a part number? Something just does not sound right about this. You should be having no problems.

If you have a meter, can you measure the resistance of the heating element?

If you have never used a PID controller before, it works by relying on the thermal mass of whatever you are heating. The controller turns on its output, this turns on the SSR, which then provides power to the heater. The heater gets hotter. The controller turns off its output, which removes drive from the SSR, which then turns off at the end of whatever AC cycle it was in the middle of. The heater then gets cooler, until the next time that the controller output turns on the SSR again. There should be enough thermal mass in the heater that there is not much change when the heater turns on vs when it turns off again, for the CtL parameter that you use. The SSR has to be controlling AC current, otherwise once turned on it will never turn off. You cannot use a normal one to switch DC power on and off. If you use DC voltage, the controller will probably work OK, but the SSR will not.

The PID controller reads an input from the temperature probe, and uses an internal algorithm to determine what percentage of ON vs OFF time is needed in order to give the correct temperature that you programmed into the controller.

If you have the CtL parameter set to 0.5, then the LED on the SSR should flash briefly 2 times per second. If it is set to 1.0, then it should flash once per second, and so on. If it is staying on solid, then something is wrong.

If everything seems to be working correctly, but the heater is still overheating, then adjust Oph from 25 down to 10 or 5, or even 1, just to see how large this number can be before you have problems with too much heat.

[Edited on 8-15-2018 by WGTR]

JJay - 15-8-2018 at 13:12

Here's the problem: Your dimmer is only 500 watts. You may have a 500 watt heating tape, but it's rated at 110 volts, so it has the resistance of a 2000 watt heating tape. Your dimmer was not designed to deal with a 2000 watt heating tape, so you need a new dimmer.

TheMrbunGee mentioned earlier that the dimmer's wattage was too low.

I suggest working out the math yourself because you will be the one using the apparatus.




[Edited on 15-8-2018 by JJay]

razor0109 - 15-8-2018 at 14:20

Quote: Originally posted by WGTR  
Can you post a picture of the heater, or a part number? Something just does not sound right about this. You should be having no problems.

If you have a meter, can you measure the resistance of the heating element?

If you have never used a PID controller before, it works by relying on the thermal mass of whatever you are heating. The controller turns on its output, this turns on the SSR, which then provides power to the heater. The heater gets hotter. The controller turns off its output, which removes drive from the SSR, which then turns off at the end of whatever AC cycle it was in the middle of. The heater then gets cooler, until the next time that the controller output turns on the SSR again. There should be enough thermal mass in the heater that there is not much change when the heater turns on vs when it turns off again, for the CtL parameter that you use. The SSR has to be controlling AC current, otherwise once turned on it will never turn off. You cannot use a normal one to switch DC power on and off. If you use DC voltage, the controller will probably work OK, but the SSR will not.

The PID controller reads an input from the temperature probe, and uses an internal algorithm to determine what percentage of ON vs OFF time is needed in order to give the correct temperature that you programmed into the controller.

If you have the CtL parameter set to 0.5, then the LED on the SSR should flash briefly 2 times per second. If it is set to 1.0, then it should flash once per second, and so on. If it is staying on solid, then something is wrong.

If everything seems to be working correctly, but the heater is still overheating, then adjust Oph from 25 down to 10 or 5, or even 1, just to see how large this number can be before you have problems with too much heat.

[Edited on 8-15-2018 by WGTR]


Thank you for explaining how the PID works.

I measured the resistance by probing the detachable two way plug and I got 36 Ohms. Also, I use AC to power the whole circuit.

The SSR does not blink with Ctl set to 1 (this is the lowest setting for me) 1 time / second. It just stays bright for a few seconds, and heats the tape until I shut it off due to the fumes. I will double check the settings.

Please check the picture I attached with the part number.



[Edited on 15-8-2018 by razor0109]

[Edited on 15-8-2018 by razor0109]

Capture123.PNG - 875kB

WGTR - 15-8-2018 at 15:15

Quote: Originally posted by razor0109  

Thank you for explaining how the PID works.

I measured the resistance by probing the detachable two way plug and I got 36 Ohms. Also, I use AC to power the whole circuit.

The SSR does not blink with Ctl set to 1 (this is the lowest setting for me) 1 time / second. It just stays bright for a few seconds, and heats the tape until I shut it off due to the fumes. I will double check the settings.

Please check the picture I attached with the part number.


OK, it sounds like there is no problem with the heater because the resistance seems normal.

If you want to, post all of the settings from the PID controller in a list, so that we can check them for problems.

As a final question, did you maybe hook the power up to the controller output accidentally, or something like this earlier? This type of thing can damage the controller.

[Edited on 8-15-2018 by WGTR]

JJay - 15-8-2018 at 16:26

I don't usually use the full cascade control model, but this will give you some idea of why you might want to use a dimmer with a PID controller: https://www.west-cs.com/news/how-does-cascade-control-work/

Cascade control permits maintaining much finer temperature ranges than using only a single controller. It sure beats watching a thermometer for hours and making microadjustments to a dial.



[Edited on 16-8-2018 by JJay]

razor0109 - 20-8-2018 at 03:18

Quote: Originally posted by WGTR  
Quote: Originally posted by razor0109  

Thank you for explaining how the PID works.

I measured the resistance by probing the detachable two way plug and I got 36 Ohms. Also, I use AC to power the whole circuit.

The SSR does not blink with Ctl set to 1 (this is the lowest setting for me) 1 time / second. It just stays bright for a few seconds, and heats the tape until I shut it off due to the fumes. I will double check the settings.

Please check the picture I attached with the part number.


OK, it sounds like there is no problem with the heater because the resistance seems normal.

If you want to, post all of the settings from the PID controller in a list, so that we can check them for problems.

As a final question, did you maybe hook the power up to the controller output accidentally, or something like this earlier? This type of thing can damage the controller.

[Edited on 8-15-2018 by WGTR]


Thanks a lot for all of your help too.

I managed to amp up the tape to reach ~300 C° while setting the duty cycle to 15%, and Ctl to 1 second without any issues. I think I may have to increase the duty cycle though in case I need higher power output (or increase Ctl setting).

JJay - 20-8-2018 at 03:49

Do not exceed 25%.

WGTR - 20-8-2018 at 04:22

I'm happy to hear it is working for you now. PID controllers are used for a wide variety of applications; whether refrigeration, heating, humidity control, etc. You're limited mainly by your imagination. If you can find a way to control something electrically, and can find a sensor to monitor a given parameter, then you can probably control the whole loop with the PID controller.

wg48 - 20-8-2018 at 05:15

Quote: Originally posted by razor0109  
[
Thanks a lot for all of your help too.

I managed to amp up the tape to reach ~300 C° while setting the duty cycle to 15%, and Ctl to 1 second without any issues. I think I may have to increase the duty cycle though in case I need higher power output (or increase Ctl setting).


Is that without the dimmer? if yes how much did the PID cost and its full model number and do you have a link to the seller?

razor0109 - 22-8-2018 at 23:31

Quote: Originally posted by wg48  
Quote: Originally posted by razor0109  
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Thanks a lot for all of your help too.

I managed to amp up the tape to reach ~300 C° while setting the duty cycle to 15%, and Ctl to 1 second without any issues. I think I may have to increase the duty cycle though in case I need higher power output (or increase Ctl setting).


Is that without the dimmer? if yes how much did the PID cost and its full model number and do you have a link to the seller?


Yes, without using a dimmer.

Here is the PID I bought:

https://www.ebay.com/itm/INKBIRD-ITC-100VH-220V-PID-Digital-...

JJay - 23-8-2018 at 01:17

I have a very similar one. The manual for mine encourages leaving the duty cycle at 0-100%, so I've never changed it.

wg48 - 24-8-2018 at 05:58

Quote: Originally posted by razor0109  


Yes, without using a dimmer.

Here is the PID I bought:

https://www.ebay.com/itm/INKBIRD-ITC-100VH-220V-PID-Digital-...


Nice find Razor. That costs £20. It costs more than the ones that don't have the time pulse control but its cheaper than most that do have it.

It may be possible to increase the derivative parameter to ramp up the temperature slowly which would be very useful. Can you change the control parameters while its controlling the temperature?

The manual talks about a baud rate but I could not find any info on any serial communications or did I miss it?

JJay - 24-8-2018 at 16:50

It's possible to change the control parameters while it's live, but the interface is pretty primitive as digital interfaces go.

markx - 28-8-2018 at 00:01

It can be notoriously difficult to PID control systems that have low thermal mass and different heating and cooling rates (e.g. an overdriven heating mantle in an insulated casing).
PID controllers, especially the cheap end models, usually do not accomodate the fact that the system's heating and cooling rate may be radically different in their internal calculation model. Hence it becomes really difficult to find a set of control parameters to deal with this situation (system heats up quickly, but cools down slowly). As a result the controller may start to act really erradically, overshooting the setpoint by a great degree and fluctuating wildly. At first glance one may even think it is broken as it does not seem to do anything rational to achieve and maintain the setpoint.
One has to familiarize oneself with the functions of the control parameters thoroughly to make any sense of what is going on. "Out of the box" state of these controllers is often quite useless for driving complicated systems and the control parameters have to be tweaked thoroughly to gain any reasonable functionality out of the unit.
Also I must note that the set of control parameters is bound to a particular system that is driven by the PID. If one connects a different system to the controller, the parameters have to be changed with great probability. So it makes much sense to really build an understanding for oneself of how they work.