jerzeek

warrior

12/08/2019 at 12:31

@dirkvanvroeger made a cool topic about auto reversing a shredder
http://onearmy.world/community/forums/topic/v4-shredder-arduino-code/

olbr

starter

13/08/2019 at 07:14

The situation is this: one of the controllers works fine with any of the other components, while the other one heat up the bands way too fast (undependant of wich SSR or heatband i use.) When i checked how many amps each of the controllers drew, they both showed 0,75A when the SSR was active, wich makes this whole problem a headache.

The controller that overshoots have all the connection screws on the back, while the one that works only have the essentials. I have a feeling they are not the same type even tho they both are the REX-C100. But if this is the case, i find it really weird that it would make such a big difference.

EDIT: After checking the packaging for the controllers i see that one is ranged from 0-400c and the other one 0-999c. maybe this is the whole problem?
I ordererd the exact same controller in a quanity of 2 so they must have sent the wrong controller.

As I heard, some people have to much overheating due to cheap PID controllers, up to 20-30 degrees. As I have seen, people folks use the REX100 and I can confirm that this controller is actually pretty bad –  not just in production – as machine builder. I am actually surprised that even some machine builders uses this controller but still charge 2000 Euro for an injector – you can get a pro mill for the same price btw. – quite a game changer for most of us …

Anyways,  I’ve done some excessive tests on various PID controllers now and the winner is the INKBIRD – ITC 100V or 100R if you intend to extend your system at some point for automation. The very controller has also quite some extra safety features – software and hardware side. It performs very well ! The max. overheat I had on this one was 1.5 deg c the first time, and the second time 0.8. and it keeps the target temp. with +/- 0.9 deg c.

It also comes with a bunch optimization parameters which allows you tuning. The terminal screws are good quality too, same for the manual. The price : 34 Euro and it worth every penny.

I am updating the wiki. @davehakkens or however is in charge for customer protection and quality control, would be great you point this out somewhere. As often, we would be more happy and sleep better to let people know the better way instead of keeping everything artificially low and cheap.

thanks a lot.

update: there is an auto-tuning function on the REXC100 :
1. Hold SET button for 4 seconds, til ‘ALI’ appears
2. Press SET button again, something like ATU should appear
3. Press ‘UP’ so it shows ‘1’ for auto-tuning’ active
4. Press SET again
5. wait for 10 secs til it goes out of settings by self, or hold SET button again for 3 secs

Now the AT LED should blink whilst reaching the target temperature. It will overshoot by the usual 20-30 degcs a few times and the settles on the target temperature. The auto-tuning process may last up to 30 minutes – depends on your heatbands and sensoring.

Conclusions: it should be better in holding on target after auto-tuning but it will still overshoot by up to 30 degs.. Still, I recommend the Inkbird ITC 100 VH and I updated all wiki pages about it.

s2019

warrior

28/10/2019 at 23:52

How well and where the thermocouple is mounted is an important factor in how well the PID works. I’m using the cheapest REX-C100 clones that don’t have tunable PID and they generally go straight to temperature. It helps that my tube is aluminum and the thermocouple has its own clamping block.

yeah, a good mount definitely makes things better but if you spent a few more $$ on it – a good auto-tuning will determine the delay (ie : distance from sensor/heatband cool down & heatup, etc..) to avoid overshooting. In PID terms – it is the ‘integral’, ‘differential’ and ‘hysteresis’ which is being set by the tuning process . However, PP wise – you have often multiple heat bands with up to 10 cm in between – you want to measure the temperature in between and not too close to the heatband to get a good average. Apparently the RexC100 has a pretty poor auto-tuning nor you can set these parameters.