Controlling a solid state relay 0 - 32v with pwm output

Projects General Guidance
1

Hi,
Is it possible to control a ssr via the pwm output 0 - 5v stepping it up to 0 - 32v so i can control a mains heater?
I've been looking at op amp circuits but not sure where i would start... being a bit of a novice!

2

SSR implies "binary" i.e, either "on" or "off".
"heater" implies long period, so yes, PWM, but at rates measured in milli-Hertz.

3

it up to 0 - 32v so i can control a mains heater?

Are you sure you need this much voltage? Most SSRs have this as the maximum voltage and the minimum something under 5V.
Please post a link to the data sheet of your device as I think you are miss reading it.

As AWOL said there is no need to have a SSR that accepts PWM input with a heater, you can use the much cheaper SSRs that just do on an off and turn it on an off slowly (in the few seconds region).

4

If you look closely at the SSR datasheet I'm sure it says input requirements can range from 3-32vdc. You can drive a SSR on and off just wiring it directly to a arduino output pin as the 5vdc on signal is adequate to turn on the SSR. Also most SSR cannot be used in PWM mode as they turn on and off only at AC zero crossings. As GM said most temperature controls using SSRs just turn the heat on and off at a very slow rate, think 1 second on, 10 seconds off kind of speed, and use the temperature sensor feedback to determine the on/off time ratio need to stay at setpoint temperature. Temperature is a fairly slow changing process so doesn't normally require the higher frequency switching that most PWM controls offer.

Lefty

5

I have been looking at this controller: RS Stock No. 218-1892 but was hoping a cheaper option on ebay would do the job item number: 270774264382
i want to power up a heater or immersion from solar panels and control the output so that it only uses solar power being produced and not from the grid

6

As I said you don't need such an expensive SSR for what you need to do.

Try a search here:-
http://uk.farnell.com/jsp/search/browse.jsp?N=2031+203128&Ntk=gensearch&Ntt=solid+state+relay&Ntx=mode+matchallpartial&D=*solid*+*state*+*relay*

7

Stuy:
I have been looking at this controller: RS Stock No. 218-1892 but was hoping a cheaper option on ebay would do the job item number: 270774264382
i want to power up a heater or immersion from solar panels and control the output so that it only uses solar power being produced and not from the grid

  1. Can't find a listing on Radio Shack for the number, got a direct link?

  2. SSR are kind of expensive at retail, but as you found prices on E-bay or surplus dealers are much lower. Note that the input is 3-32vdc as I stated.

  3. Your project has some technical details to deal with before worrying about the control side of it, solar panels generate DC voltages, mains utilize AC voltages, and your heater element will be designed for a specific voltage and current level. SSR only switch AC voltages on and off, not DC voltages. How are you going to interface these different power sources to your load? This will be the more expensive and important side of this project.

  4. Keep in mind that a SSR is not a controller, it's just an output switching device. The control function includes the SSR, Arduino, and temperature sensor. Only then do you have all the pieces needed to control a process.

Lefty

8
  1. Can't find a listing on Radio Shack for the number, got a direct link?

It's here:-