MH Apex control on/off

[hkgar]

I have 3 MH on my tank and use an Apex Cntl for the 3 lights. Here is my current program:

Fallback OFF
Set OFF
If Time 11:00 to 19:00 Then ON
If Tmp > 83.5 Then OFFI would like to figure out is I can program for the lights to come back on if lower than 82.0 but only during the time period in the Time statement.

TYIA

 

[sfdan]

I think this will do what you want, but the lights will only come on in the first place if the temp is less than 82:

[mh_light]
Fallback OFF
If Tmp < 82 Then ON
If Time 19:00 To 10:59 Then OFF
If Tmp > 83.5 Then OFF
Min Time 30:00 Then OFF

The key is not to have any "SET" command so the outlet will stay in its current state if none of the conditions are met. So if you are in daytime and the temperature is 82.5, none of the statements are true, so if the light was already on it will stay on, and if it was off it will stay off. The Min Time statement is always good to have for MH lights, so in case the tank overheads the halides are guaranteed to be off for at least 30 minutes. Given the way this code works your lights almost surely would be off for that long anyways, but its just added safety.

 

[hkgar]

This was posted in to my question in the Neptune forum and works perfectly.

Fallback OFF
If Temp < 82.0 Then ON
If Temp > 83.5 Then OFF
If Time 19:00 to 10:59 Then OFF

 

[sfdan]

Great, that is functionally the same as what I wrote! I'd still recommend putting:

Min Time 30:00 Then OFF

At the end of it as a safeguard. All this statement does is say if the MH light goes from ON-->OFF, make sure it stays off for at least 30 minutes. This way if your tank happens to cool down really quickly you will still be sure the MH bulbs stay off for 30 minutes so they have time to cool down so they can re-fire.

It is also useful in the case where your temperature sensor goes on the fritz (for example the cable comes loose) and it starts ping-ponging back and forth between the actual correct value (say, 81 degrees) and some incorrect value (say, 90 degrees). Every time the temperature flips back and forth, your MH lights are going to be turning on and off, which isn't good for them.

I always make sure to have a "Min Time" statement for any piece of equipment that is regulated by temperature or pH just to make sure in case the sensor goes on the fritz none of my equipment is going to be damaged by turning on and off again every second.