ATO: OSC with Switches, Program Check

[rjinct]

Hi All,

This is the first time programming switches with a B/O box while also using the OSC command. Would some of you experts take a look and point out any potential problems? It appears to be working correctly based on testing, but have not yet committed to this pushing water...yet.

This is what I'm trying to do: I want the Apex to limit the topoff process to 4 minutes an hour at most, but also take into account a high and low float switches in my sump. When the low switch is ON, it should top off. If for some reason that switch remains on, and the high switch turns on, it should kill the topoff process. Also I don't want it to run between the hours of 5-8 while my auto water change is running.

Please let em know if you see any issues here. Thanks in Advance!

**Top OFF**
Fallback OFF
Set OFF
OSC 000:00/004:00/056:00 Then ON
If Outlet TopOffLow_A1 = OFF Then OFF
If Outlet TopOffHigh_A = ON Then OFF
If Time 17:00 to 20:00 Then OFF

**TopOffLow_A1**
Set OFF
If Switch1 CLOSED Then ON

**TopOffHigh_A**
Set OFF
If Switch2 CLOSED Then ON

 

[aquamanic]

Keep in mind that if your sump needs more than 4 minutes of water to bring it up to level, you won't get it. That could get progressively worse over time to where you run low but the ATO is functioning correctly - just doesn't have enough time to fill.

You could use a Min Time statement instead of the OSC to keep it OFF for 45 minutes yet still enable it to take whatever time required to fill. If it needed 8 minutes to fill, it would have it, then wait at least 45 minutes before attempting to top off again.

Here's my program with a similar 2 float setup:

Fallback OFF
Set OFF
If Outlet Sump_Low = ON Then ON
If Outlet Sump_High = ON Then OFF
Min Time 060:00 Then OFF

 

[rjinct]

Keep in mind that if your sump needs more than 4 minutes of water to bring it up to level, you won't get it. That could get progressively worse over time to where you run low but the ATO is functioning correctly - just doesn't have enough time to fill.

You could use a Min Time statement instead of the OSC to keep it OFF for 45 minutes yet still enable it to take whatever time required to fill. If it needed 8 minutes to fill, it would have it, then wait at least 45 minutes before attempting to top off again.

Here's my program with a similar 2 float setup:

Fallback OFF
Set OFF
If Outlet Sump_Low = ON Then ON
If Outlet Sump_High = ON Then OFF
Min Time 060:00 Then OFF

Thanks a great point...I didn't think of that. I guess I was trying to incorporate another failsafe if both float switches both failed to stop the pump...and limit the amount of topoff water that could be added at any one time. I don't recall seeing a command that would limit the state an outlet is at after it's been turned on, is there? Or would adding a Min Time / ON work? For example:

Fallback OFF
Set OFF
If Outlet Sump_Low = ON Then ON
Min Time 015:00 Then ON
If Outlet Sump_Low = OFF Then OFF
If Outlet Sump_High = ON Then OFF
Min Time 045:00 Then OFF

Although looking at it this some more, seems I may have just recreated the OSC command...and would still run into the same issue you previously described if I could not top off within 15 min.

 

[aquamanic]

No, you're really muddying the waters now. If you try to use Min Time to establish the outlet run time, all you're going to get is forcing the outlet to stay on for 15 minutes - if it only needs 3 min to fill, then you're going to over-fill by 12 minutes. The purpose of the floats is to get just what you need from the ATO - no more, no less.

I would rely on your two floats as-is and use Min Time (or Defer) to keep the ATO from short-cycling. That way it works summer and winter regardless of evaporation and both floats would have to fail for you to have a problem.

 

[rjinct]

Ok, I see how my previous example would really muck things up. I figured that the Min time would get overridden by any subsequent statements. So is it accurate to say that Min time should probably be the last statement within any program?

 

[aquamanic]

It doesn't matter where the Min Time is in the program, it applies to the entire outlet. You have two in there, one for Then ON and one for Then OFF, which is legal syntax. I find it easier to conceptualize if at the end but it doesn't have to be there.

The Min Time and Defer are the only two statements that this is true of.

 

[swearint]

Min Time means literally 'a minimum duration'. So Min Time ...ON will keep the outlet ON for at least the specified duration before it can be changed to OFF by another condition.

Actually, your original approach is basically what I use. I have snails in my sump that occasionally camp out on the float and create a false low signal. So I looked at my typical daily topup runtime, using the outlet graph, and selected an OSC duration that was a bit more than necessary to refill the sump. It basically creates allowable 'windows of time' that topup can occur. Alan's approach is easier though and should cover most circumstances.

Todd