DOS Speed Not Matching the Program

[ian14723]

I'm having a little bit of a issue with the speed of my DOS. I have it programmed to fill up the TOP-OFF tank next to the aquarium. Consequently, I (believe) I have it programmed for 100000mL over a 24hr period, only to be shut off should should an optical sensor in the TOP-OFF tank register as closed.

The Interval is set as 00:00 to 23:59 for 100000 mL. This should be at a 4166 mL per Hour rate.

The program is set to advanced:
Fallback OFF
tdata 00:00:00,1,16,27,81,2,88,143,27,82,2,28,10,0
Set OFF
If TOPOFF OPEN Then ON
If TOPOFF CLOSED Then OFF
Defer 000:10 Then ON
Defer 000:05 Then OFF

However, the DOS only delivers at a rate approximately 10% of that above even when the TOPOFF sensor is still Open.

What am I doing wrong?

[zombie]

You are overwriting the wizard with the set and on statements. Change to this.

Fallback OFF
tdata 00:00:00,1,16,27,81,2,88,143,27,82,2,28,10,0
If TOPOFF CLOSED Then OFF
Defer 000:10 Then ON
Defer 000:05 Then OFF

You will wear out your heads pretty quickly if you are really topping off 12 gallons a day. It might be worth considering an alternative like an Avast diaphragm pump for better long term running costs and repurposing the DOS for AWC or dosing. If you aren't topping off 12 gallons a day, the wizard should be set to about 2x what your tank evaporates in a typical day.


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[RussM]

Your programming is wrong.... I suspect that you are overthinking things and making it harder than it needs to be.

First, you should not have a Set OFF in the advanced box. That overrides and effectively negates the tdata above it (tdata is the programming generated by the DŌS wizard/scheduler).

Second, the If switch statements are not used properly:

If TOPOFF OPEN Then ON
If TOPOFF CLOSED Then OFF

You should not be testing both switch states and setting ON if OPEN and OFF if CLOSED. Those two statements are completely controlling the DŌS operation; they effectively override all programming above it. In this case, you need to use only "If TOPOFF CLOSED Then OFF" so it stops the refill process when the reservoir is full.

When you put a DŌS to ON, it runs at 25ml/minute, not at its max speed of 250ml/minute; because you are incorrectly using the switch state to turn it ON, you are not getting the expected higher speed. The DŌS also does not run continuously; instead, it doses small amounts frequently. When you use the wizard, the internal algorithm uses the specified time window and the specified total daily amount to determine the amount of each individual dose, how often to repeat a dose, and the slowest pump speed that can be used to deliver the desired daily volume in the desired period.

The only programming that you really need is the tdata (created by the wizard) and a single If switch statement:

tdata 00:00:00,1,16,27,81,2,88,143,27,82,2,28,10,0
If TOPOFF CLOSED Then OFF

You don't even need the Fallback OFF because Fallback OFF is hard-coded into the DŌS firmware - it is not user-configurable. The wizard inserts the Fallback OFF statement simply as a reminder of that.

That all being said, another issue may be the concept you are using. It won't "refill" the reservoir when the reservoir is low - instead, it will just keep the reservoir full at all times. Essentially, you are just topping off the top-off reservoir. Also, allowing the DŌS to pump 100 liters/day is probably excessive (unless you have a rather large ATO reservoir!). Adjust the volume to be about 3 times the typical daily ATO usage. You will probably find that the DŌS runs relatively frequently and only for shorts periods. You can use Defer statements to make the DŌS run longer per run at greater intervals, but the Defer 000:10 Then ON & Defer 000:05 Then OFF are way too short for this application. Instead, I'd use:

Min Time 030:00 Then OFF - keeps the DŌS from running again unless at least 30 minutes has elapsed since it's last run
Defer 005:00 Then OFF - causes the DŌS to keep topping off the top-off for 5 minutes after the switch goes CLOSED, resulting in a slight (but desirable) overfill, which also serves to reduce frequent pump cycling. 5 minutes is quite conservative in this case; You could probably make this 15 minutes (or longer) in duration, depending on how volume difference there is between the switch and the top of the reservoir.

[ian14723]

Thanks. That has solved it. I have reduced the amount by half. Now the DOS runs at what I feel is a desirable speed. I'll check on the evaporation rate when I have more data and adjust the speed of the DOS accordingly.

Many thanks again.