Which signal is better to drive a solid state relay: 4-20mA, 0-10V or 0-1 PWM signal?

Question

Electronics

There is a boiler with heating elements. It is necessary to choose the principle of control of a solid state relay.

Answer 1

Since the boiler is a very inertial thing, "PWM at a very low frequency" is enough for it - like in an iron or a heater.
In short, the choice of control method depends on the control algorithm, and the algorithm depends on the complete statement of the problem.
Unless 4-20mA looks like nonsense, because the relay is about on-off, and not about proportion.

Answer 2

Principle electrical? No hardness data available .
Or the TAU principle? Then there is no data on the inertia of the system, available power, heat losses and required accuracy.
As always, the right question is half the answer.

Answer 3

And what's the problem with taking the manufacturer's datasheet and looking at its parameters?