ACIII hysteresis program

[fishcam]

I've got the following safety code in my ACIII, and I want to check that I'm using the max change command right. Basically in the event of a power down because of temperature, I want to wait 30 mins before attempting to power down again. Ideally this would work when the temp is 82.1, lights are off, 82, lights go on and heat up a little, to turn off again when temp gets to 82.1.

 

Here's my whole program, which controls the lights, heaters, cooling fans, and dosing pumps. I'm open to different methods of implementation if you have any too

 

Thanks for the help.

 

If Time > 13:00	   Then LT1 ON 
If Time > 23:00	   Then LT1 OFF
If Time > 13:30	   Then LT2 ON 
If Time > 22:30	   Then LT2 OFF
If Temp  > 82.0	  Then LT1 OFF
Max Change 030 M	  Then LT1 OFF
If Temp  > 82.0	  Then LT2 OFF
Max Change 030 M	  Then LT2 OFF
If Temp  > 78.0	  Then COL ON 
If Temp  < 77.5	  Then COL OFF
If Temp  < 77.0	  Then HET ON 
If Temp  > 77.5	  Then HET OFF
If Time > 05:00	   Then CAL ON 
If Time > 05:30	   Then CAL OFF
If Time > 06:30	   Then ALK ON 
If Time > 06:36	   Then ALK OFF
If Time > 07:30	   Then ALK ON 
If Time > 07:36	   Then ALK OFF
If Time > 08:30	   Then ALK ON 
If Time > 08:36	   Then ALK OFF
If Time > 09:30	   Then ALK ON 
If Time > 09:36	   Then ALK OFF
If Time > 10:30	   Then ALK ON 
If Time > 10:36	   Then ALK OFF

[Neilan]

You don't have your 2 lights on the same duration. This will cause 1 bulb to wear out/shift faster than the other.

 

I think If Time > 22:30 Then LT2 OFF

should be 23:30

Edited April 26, 2009 by Neilan

[ctenophore]

Just looking at code is not a good way to verify correctness- you need to test it. Take the temp probe out and hold it in your hand for a few minutes. Does the AC3 do what you want?

 

Try to create as many exceptional conditions as possible, and see how your system reacts. High temp, low temp, power outages, low/high sump water, etc.

[fishcam]

You don't have your 2 lights on the same duration. This will cause 1 bulb to wear out/shift faster than the other.

 

I think If Time > 22:30 Then LT2 OFF

should be 23:30

 

Thanks for the thought, but I like the sunrise, sunset type look. Since the blue PC's dont really help the coral much, I'm not sure I'll replace them when I replace the MH's (10k 150's).

[fishcam]

Just looking at code is not a good way to verify correctness- you need to test it. Take the temp probe out and hold it in your hand for a few minutes. Does the AC3 do what you want?

 

Try to create as many exceptional conditions as possible, and see how your system reacts. High temp, low temp, power outages, low/high sump water, etc.

 

Thanks and will do. I've got a pretty thorough failure scenario worked out already, and was just curious if someone who knew the ACIII code could confirm. In my tests it seems to work (today is a hot day!) but to the end of redundancy, I wanted a second pair of eyes.

[Origami]

As I see it, both LT1 and LT2 will be turned off for a minimum of 30 minutes which is the purpose of the MAX CHANGE statement. If the temp goes above 82 degrees, your tank goes dark all at once. This will work fine but you might consider shutting one light (say LT2) down at a lower temperature just in case that's sufficient to drop the heat load.

 

Your staggering of lights is typical of a gradual lighting program. Many of us do it. I wouldn't worry about asymmetric aging of the bulbs.

[Sikryd]

I don't know how much your lights heat up the water or what temp you set your house to (AC wise) which can make a huge difference.

 

But I set my temp @ 76.5 on the heaters - which makes the daytime temp about 78 or so. Running into 82 - THEN shutting the lights off seems a bit late since the water is still being heated and will go up higher, sometimes quicker than we think - especially during the day.

The highest I want my tank to go is 80 - above that and things start looking bad - down to 74 and everything is fine too - so I like to keep in on the lower end of the high side for safety.

 

I keep my house at a constant 72 year round which also affects the amount of heat from the lights that reaches the water.

I am still working on mine to stabilize it since this is the first weekend with higher temps that I needed to turn my AC on, so I am still figuring out and adjusting the temps accordingly.