electrical gurus
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bobbyrobie
- Posts: 124
- Joined: Wed Sep 17, 2008 9:17 pm
All right !
That's my turn to ask a question to the electrical gurus !
I've wired my PID controllers, SSRs and all the stuff, just need to receive the blankets now (I'll get them on Friday) but I'm already having a look at how to set the PID controllers.
I mean all the tuning, not the actual set temperature... not SOOO dumb
So far it seems to work with the supplied K type thermocouples, the temperature displayed is OK and I managed to adjust the set value but I don't know yet if the output is doing a good job, I just can hear some "clicks" but don't know where they are from (PID or SSR?) and even if the temperature from the TC is more than the set value it's still "clicking"...
Anyway... I might end up using the auto-tuning setting which seems to be enough from what I understood but there is a parameter I don't really get... it's called the "control output cycle" and is factory set at 20 seconds... can someone help me understand what this is ? it seems to me that a 20sec cycle it ways too long to have an accurate control... but I guess I just don't get it (don't forget I'm French, so this translated-from-chinese-technical-stuff is quite tough to understand...)
Just for info I got my PIDs from ebay and here is a link to their instruction manuals:
http://www.sure-electronics.net/measure ... 1.0_EN.pdf
Any help will be appreciated !
Thanks guys !
That's my turn to ask a question to the electrical gurus !
I've wired my PID controllers, SSRs and all the stuff, just need to receive the blankets now (I'll get them on Friday) but I'm already having a look at how to set the PID controllers.
I mean all the tuning, not the actual set temperature... not SOOO dumb
So far it seems to work with the supplied K type thermocouples, the temperature displayed is OK and I managed to adjust the set value but I don't know yet if the output is doing a good job, I just can hear some "clicks" but don't know where they are from (PID or SSR?) and even if the temperature from the TC is more than the set value it's still "clicking"...
Anyway... I might end up using the auto-tuning setting which seems to be enough from what I understood but there is a parameter I don't really get... it's called the "control output cycle" and is factory set at 20 seconds... can someone help me understand what this is ? it seems to me that a 20sec cycle it ways too long to have an accurate control... but I guess I just don't get it (don't forget I'm French, so this translated-from-chinese-technical-stuff is quite tough to understand...)
Just for info I got my PIDs from ebay and here is a link to their instruction manuals:
http://www.sure-electronics.net/measure ... 1.0_EN.pdf
Any help will be appreciated !
Thanks guys !
A bad day skiing is always better than a good one at work...
Did you get a voltage output or relay output? If you got the voltage output, there really shouldn't be any clicking since every thing should be solid state. There might be some alarm relays that may be clicking.
Auto-tune is usually fine. Since you are using SSRs, then you can decrease the control cycle to be pretty fast, 1 sec or so.
-kelvin
Auto-tune is usually fine. Since you are using SSRs, then you can decrease the control cycle to be pretty fast, 1 sec or so.
-kelvin
The control cycle time is the time it takes for one On/Off cycle. The amount of time On is proportional (P in PID) to the power needed. So if the controller determines that you need 60% power with a cycle time of 20sec, then it will turn on the heater for 12 sec and off for 8 sec.
Faster cycle times gives you better control, but is harder on the components. This is more important in mechanical relays. For slow systems like a heat circuit, you also do not need super fast cycle times. I think I use about 3 seconds on mine.
-kelvin
Faster cycle times gives you better control, but is harder on the components. This is more important in mechanical relays. For slow systems like a heat circuit, you also do not need super fast cycle times. I think I use about 3 seconds on mine.
-kelvin