Relays - Controlling voltage flowing for heater elements to maintain temperature

[Etude]

So I have a UT130 Temperature Controller turning on and off a heater element through a SSR relay to maintain the temperature of water at a constant temperature. But the problem is that the temperature will still fluctuate making the relay go on and off continuously. I need the water to stay at the set temperature and not rise and fall around the set point.

Right now, the relay turns on (and so the heater) when the temperature falls below 100 and vice versa. Is there any kind of relay that allows me to control the voltage flowing through it? As in: while heating up, as the temperature gets closer to the set point, the voltage flowing through the relay and heater decrease in some ratio (i.e. the relay doesn't turn on and shut off completely) so that the temperature doesn't rise above the set point and so hopefully gives a more stable temperature? I tried searching but can't seem to find one!

 

[Integral]

google PID temperature control

It is software more then hardware.

You may be able to get good enough temperature control just set up a dead band. So if you want 90C water set the heaters to turn on at 85C and off at 95C. These are just numbers pulled from the air, set the set point and width of the dead band as you need.

 

[Integral]

Just googled your controller. It can do what you need. However the manual is very cryptic. If this is your first controller, good luck.

Study the manual, learn to navigate the menus of your controller.

You will need to have a basic understanding of PID control to get anywhere, so will need to be reading and understanding PID control at the same time you learn to run the controller.

You need to get to the self tuning setting and trigger self tuning. Once that is done your controller should do fine. If you have the supporting hardware set up correctly.

 

[Etude]

Hi Integral.
Yup I saw the PID control and that it auto tunes.
So is that enough for maintaining stable temperature? I thought that the PID control should be enough but this guy with me doesn't seem to think so. :P
Well, thank you, I guess I ll just set the whole thing up and see who it works.
For curiosity, are such relays available?
Thanks for your help!

 

[Integral]

Not to my knowledge, this is what PID controllers do.

 

[Etude]

Okies! Thanx a lot again! :)