PID protection

[Humuleneman]

Can somebody put a light on my questioning. Im planning on a control panel that works only on 240 volts. im using a camco 5500w element. The power to this element is controlled by a auber SYL-2352 PID and a 40amp SSR. My concern is the following. will the rapid switching of the element will cause a surge problem and damage my PID? is there a way to isolate or damp the 240v circuit for the PID?
thanks

Humuleneman.

 

[FastTalker]

You won't have a problem. If you're really concerned you could use a transformer to isolate power to the PID or use a line reactor on your heater, but that is entirely unnecessary for a resistive heating element.

 

[Zepth]

Nope, the PID will be fine. That is what it's designed to do, and as mentioned a resistive element isn't going to put any noise into the system. If memory serves the PID syncs on off cycles with the waveform of power transmission.

Side note: If your system happens to short out the SSR will fail. Guess how I know...

Alright the story with that is that somehow my ground wire came loose on the kettle side of things and tapped the hot connection. Fried the SSR, popped the breaker, otherwise all is well. Ironic that it is the ground wire that actually caused the issue.

 

[Humuleneman]

Thanks. I was just trying to protect my investment. Auber PID are a little expensive. I have another question for you. Is it possible to use 2 x syl- 2352 PID with a 3 way switch to control the signal to a single SSR. I heard its not ok for 2 rtd´s probes but does the PID knows if a SSR is connected to the 12 v output?

 

[Zepth]

In theory if you could isolate the outputs of the PIDs so they don't back feed into each other you could. I have no clue if back feeding on the output side would cause damage or not, when in doubt isolate. I would assume the output side of the PID is a simple relay circuit, doesn't matter if anything is there or not it will switch as it sees fit.

That all said if the main question of the thread is "PID Protection" why risk it? Get a second SSR and run it off the second PID.

 

[Humuleneman]

Thanks.

 

[Brumateur]

I heard its not ok for 2 rtd´s probes

It's not true. You can connect two 3 wire RTD probe to one PID using one DPDT switch with no problem.

 

[Humuleneman]

I just read that the resistance from one RTD's is outputted to temp and may have to be corrected with the input offset (Pb) on the auber SYL-2352. When you swith to another RTD's it may give another reading if the resistance is not quite the same. Wire length, connector , two Pt100 from different brand or even the switch can give diffenrent ohms reading at the same temp. Im not saying it's impossible. they even show you how on aubers http://www.auberins.com/index.php?main_page=page&id=11
sorry for the mistake

 

[augiedoggy]

For the record the pids run on 24v dc... you feed them ac power but they have a small dc powersupply inside that they actually run on .