PID Control Issues Need Help

[Bigarcherynut]

My E-Kettle is finished and I’m gong to run my first batch tomorrow but unfortunately I’m going to have to watch it and run manually. My PID controller doesn’t seem to work correctly and I’ve been searching for answers but have not found one. I did find an older thread that the person had the same problems but no answers.

I have an Auber SYL-2362 PID controller and a FOTEK SSR-40 DA solid state relay.

Here are my problems.

1. Cannot get the controller to work in PID control mode or do an Auto Tune. I have double checked the settings and all is correct. When I do an auto tune it hits set point and continues to heat and never shuts off. After several attempts I gave up. I ran the controller in PID mode and it never shuts off. Continues to heat. Any ideas?

2. I decided to run the controller in “Control Output #1”. It appeared to work correctly. The red indicator on the controller turns off when it hits set point, the light on the SSR goes off, the 8v DC output to the SSR turns off but the SSR relay continues to pass voltage. My element wiring is similar to PJ”s Single Element BIAB PID. What I have found is if set point is reached and the DC output to the SSR turns off the SSR still passes voltage to the element. If I switch power off to the contactor coil that is ahead of the element and then turn it back on the SSR does not pass voltage anymore when turned back on. It appears the SSR relay latches and continues to pass voltage even when the DC input is turned off.

May try and call Auber if I can’t get any answers here.

 

[Bobby_M]

Sounds like a bad SSR.

 

[Bigarcherynut]

Sounds like a bad SSR.

Just put another one in. Brand new.

 

[mattd2]

Just put another one in. Brand new.

How many amps are you putting through them? I have seen some info that knock-off 40A Futek's being 2x 20amp triac side by side without any means to ensure load sharing. If the load is over 20A there is a definite chance it can destroy one of the triacs then the other.
The other question is what heatsink do you have them on?

As for the PID - how long did you let the Autotune run for? During the Autotune it is learning your system based on some guess of appropriate P, I and D settings. These may be way off for your system causing overshoot during the Autotune.

 

[Bigarcherynut]

How many amps are you putting through them? I have seen some info that knock-off 40A Futek's being 2x 20amp triac side by side without any means to ensure load sharing. If the load is over 20A there is a definite chance it can destroy one of the triacs then the other.
The other question is what heatsink do you have them on?

As for the PID - how long did you let the Autotune run for? During the Autotune it is learning your system based on some guess of appropriate P, I and D settings. These may be way off for your system causing overshoot during the Autotune.

I have a 4500 watt element at 240v so about 18.75 amps.

I used a heat sink out of a PC which measures 2-3/4" x 2-3/4" x 1-3/4" deep with a cooling fan mounted on it.

As for Auto Tune I ran it for at least 45 - 60 minutes with a set point of 150 Deg and was at 205 when I shut it off. Figured it should have shutoff and cycled back to below set point.

 

[Bigarcherynut]

Ok it appears that it's SSR related not the PID controller. If the DC signal is "On" more than 15 seconds to the SSR once the DC signal shuts "Off", The FOTEK SSR-40-DA will continue to pass current which keeps the heating element heating.

Has anyone expienced this?

Going to buy another brand.

 

[WScottCross]

There have been quite a few reports of faulty Fotek SSR's. Some of them are reported to be 2 20A triacs with no load sharing scheme. I would avoid Fotek SSR's if at all possible.

 

[augiedoggy]

There have been quite a few reports of faulty Fotek SSR's. Some of them are reported to be 2 20A triacs with no load sharing scheme. I would avoid Fotek SSR's if at all possible.

I agree... most of the ones on amazon and ebay are fake clones... I got lucky with the 3 I used and 2 are fakes.

I would look at this one... http://www.ebay.com/itm/Mager-40A-S...7?hash=item5b1e280583:g:MWoAAOSwo0JWJzxJThese are good quality ssr's
Mager is the oem supplier of all the ssr's aubrins rebrands and sells under thier name.. if you compare them side by side you will find even the sticker design/ layout and model numbers are the same except auberins uses a different color sticker and or course they use their own brand name and charge double for it.

 

[Bigarcherynut]

I agree... most of the ones on amazon and ebay are fake clones... I got lucky with the 3 I used and 2 are fakes.

I would look at this one... http://www.ebay.com/itm/Mager-40A-S...7?hash=item5b1e280583:g:MWoAAOSwo0JWJzxJThese are good quality ssr's
Mager is the oem supplier of all the ssr's aubrins rebrands and sells under thier name.. if you compare them side by side you will find even the sticker design/ layout and model numbers are the same except auberins uses a different color sticker and or course they use their own brand name and charge double for it.

I ended up buying one from Aubrins seeing I'm using their PID controller. They've been working with me on the problem. Been fast and helpful.

Thanks

 

[Bigarcherynut]

Well I got the controller working. Came down to bad SSR's from FOTEK. Only 1 out of 3 ended up working right.

WARNING TO ALL. STAY AWAY FROM THE FOTEK RELAYS.

Well I'll see how the system works on my next batch this weekend.

 

[augiedoggy]

Well I got the controller working. Came down to bad SSR's from FOTEK. Only 1 out of 3 ended up working right.

WARNING TO ALL. STAY AWAY FROM THE FOTEK RELAYS.

Well I'll see how the system works on my next batch this weekend.

yeah if you do a search here you will find a few threads basically saying the same thing... They have a pretty high failure rate. again most are generic fakes with a fotek sticker on them...