What is the best or correct way to control these?
I started by using an opto-isolated relay, but after a while the (non-official) Nano would stop working. So I started looking for other methods.
Currently I've been waiting 3 months for a dimmer module, and now have some triacs and optocouplers on the way too.
Are these the way to go, but considering this is a common item to use I'm guessing there should be a standard module that is safe for me to use with my still limited experience.
Any help or suggestions welcomed and thanked, cheers
Example of item in question (90W 220V AC Electric Heating Element Mica Band Heater):
You ask: What is the best or correct way to control these?
All depends on what you mean by control. Simple on-off, or variable temperature?
The simplest is to use a solid state relay, which is what they show in the ad you linked to. Any Arduino will work to do that. I have one running a SSR to control the irrigation water tank and it has performed flawlessly for a year, now.
Sorry, yes you're right, more detail.
I'm trying to get it to a variably set temperature and keep it there, not simply on and off. (Melting plastic)
I too would expect it (relay) to perform without issue, however two boards have started acting up after being used on that project. I was wondering if there is anything similar to another recent issue of mine, of some kind of EMF being given off a cheap motor which affects the Hall Effect Sensor and crashes the controller (so I've added bypass capacitors and flyback diodes).
TBH, that link was random, I hadn't even looked at any of the details.
So, it may be the boards rather than the system that uses a relay and I should persevere. I'll still try the triac method so as to avoid the clicking relay noise.
SSR does not "click". What are you using for temperature feed back? What is the delay between powering the heater and it exceeding the set temperature? Same on removing the power. How long before temp goes belog the set point?
Thankyou for the SSR Relay tip (guessing Solid State Relay)
I was at the stage of studying how it heated, was using a 10K thermistor, have now got some 3D Printer 100K thermistors too, however also using a hand held thermometer I use with my kiln.
As Paul was hinting at you need to set TWO points and monitor those.
One is low temp and one would be high temp.
Bear in mind there may be a period at either point where you might need to ignore the reading.
Eg.. for low point anywhere between 60 and 70 deg C and for high point anywhere between 90 and 100 deg C (example only)
You almost certainly need to filter the PSU for the Arduino and add any filtering needed for AC motors too.
Even better if you can power your AC motors from a slightly different circuit in the house etc.
Not sure how much heat you need to input to your water as you don't give enough detail.
The element you looked at will only produce a small amount of heat and that will also depend on the water flow.