Doser stopped dosing automatically

[mlandscape]

I am not sure why but my 2.1 SA doser has stopped dosing automatically and I dont know why.
I seems that it may have stopped dosing when the clock changed and/or I changed the dose and changed the pump speed but I did recalibrate after that change of speed.
It works correctly when I dose a fixed amount manually.

I have attched screenshots of the relevant pump and wondered if anyone can see if there is amything wrong with the set up

Mnay thanks

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[Vinny]

For the amount you're looking to dose, it would be better to run the pump at speed (0).
Recalibrate at the new speed, then allow the pump to run the set schedule.

[mlandscape]

For the amount you're looking to dose, it would be better to run the pump at speed (0).
Recalibrate at the new speed, then allow the pump to run the set schedule.

I altered speed to 0 and recalibrated and on first scheduled dose only dosed about 0.5ml not sure why ?

Maybe I didnt calibrate properly or save it. What I do recall is that when I calibrated originally it showed 20 ml in minute and when I recalibrated at 0 it dosed 21 ml in minute which I thought was strange at the time.
After this recalibration at 0 speed only dosed 6ml in minute.

See what happens at next scheduled dose tomorrow hopefully will be OK.

[Vinny]

As long as you pressed SAVE after selecting the new pump speed, it will run at the correct speed. After calibration, you will get a flow rate of about 4-5ml/min.

[mlandscape]

I suspect I didn’t save before calibrating the first time. When I did again it was 6 ml per min

[mlandscape]

@Vinney well it dosed but the only 1ml not 1.5ml I wanted.
That was after changing speed to 0, recalibrating which indicated flow rate 6ml per minute.
I have calibrated again and still showing 6 ml per minute.
Any further suggestions, please ?

[Vinny]

This suggests an issue with the calibration attempt. The best way to calibrate is to use a measuring scale. Some measuring cups are not as accurate, especially for such small and precise volumes like 1.5ml

[mlandscape]

This suggests an issue with the calibration attempt. The best way to calibrate is to use a measuring scale. Some measuring cups are not as accurate, especially for such small and precise volumes like 1.5ml

Not sure what you mean by measuring scale? The measuring cup I am using is only a total of 5ml so I would expect to be fairly accurate. Not sure I would expect to have to go to such great lengths to calibrate a dosing pump. Not had such issues before with similar pumps

[Vinny]

Those similar pumps did not have to be calibrated to provide the degree of precision you're now aiming for (1.5ml). To achieve the best result for such small dose amounts, you should be using a tool more accurate than a traditional measuring cup.
Here's an example (https://www.amazon.com/dp/B07H3CPPT9/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B07H3CPPT9&pd_rd_w=fvDXT&pf_rd_p=48d372c1-f7e1-4b8b-9d02-4bd86f5158c5&pd_rd_wg=ngdm1&pf_rd_r=GBBZ06R8X6ZSD1JR9SQA&pd_rd_r=8051f7bc-076c-465d-834e-27121782b732&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFNQTRIUjBTUk84M0UmZ W5jcnlwdGVkSWQ9QTAwMTMyMjMxNFA4RUhGQ09OODEyJmVuY3J 5cHRlZEFkSWQ9QTA5OTM1NTRORTU2UFRZODZQS1omd2lkZ2V0T mFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9 Ob3RMb2dDbGljaz10cnVl) of one that would be suitable.

[mlandscape]

Sorry but that doesnt really help me slove the rpoblem

[Vinny]

We provided an example of a digital scale so you can use a more precise calibration tool for calibrating...how does that not help solve the problem? :confused:
The pump is running as commanded. The inaccuracy is a direct result of the calibration attempt.

[mlandscape]

We provided an example of a digital scale so you can use a more precise calibration tool for calibrating...how does that not help solve the problem? :confused:
The pump is running as commanded. The inaccuracy is a direct result of the calibration attempt.

Firstly can I apologise? I was using my iPhone when I replied to your post and didn't even notice the link. I have now looked at that link and unfortunately, that make/model of scale is not available in the UK and I can't find anything of the supposedly same accuracy which I have to say I find it slightly difficult to believe that it can be accurate to weigh to 0.5 ml accuracy.

I do have some similar scales(not 0.5 ml accuracy) which I have tried to use but it seems to be less accurate than the measuring cylinders etc. When calibrating dosing pumps etc most companies use/provide a measuring cylinder to calibrate and I can't recall seeing anyone advising using measuring scales. I am not suggesting that you should be providing one by the way. Even your manual says to use "A 50ml or greater graduated cylinder or beaker to measure fluid dispensed" Also your Youtube video says to use a measuring cup and/or cylinder.

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Having said all that I have tried all ways to get the pump to dispense an accurate 1.5 ml to no avail. I have tried speeds 0 and 1 and saved and calibrated numerous times and am getting differing dosed amounts most times which is concerning, to say the least. The closest I have got is 1.2/1.3 ml dosed at 0 speed and calibrated at 10ml per min and I guess I will have to go with that and monitor its effect on the aquarium and try and adjust from there as required. Not very satisfactory.

I would be interested to know if anyone else is trying to dose a similar amount of 0.5 ml accuracy and what results they are getting.

[Vinny]

No worries. :)

If you're asking the doser to dispense 1.5ml and it gives you 1.3ml, that is within the acceptable tolerances of the motor, +/- 0.2ml.
In most cases a graduated cylinder is OK to use when you're dosing much larger amounts like. Remember, that video has to accommodate most cases which means it is a general video covering calibration. It is not specific to those wanting to dose such small amounts to the tenth place, that is when the digital scale becomes more useful.

[mlandscape]

I have not seen anywhere about the +/- 0.2ml but if that's the case fair enough.

All I have seen on the website is "The 24V stepper motors allow precise dosing even at the smallest flow rates (0.1 ml)." and "Conveying capacity and dosing:8-45 ml/minute (precisely adjustable to 0.1 ml)"

It might worth some clarification on this point if what you are saying is the case.

When I acquired the doser I was not necessarily expecting such accuracy but based on what is indicated in the literature it leads you to believe that it can maintain accuracy of 0.1 ml

Many thanks

[mlandscape]

@Vinny after many calibrations this problem now seems to have settled down and dosing 1.5 ml Using Speed 0 and 4ml flow rate.
Thanks now just waiting for the arrival of a P4E and KH Director.
Hopefully, I will get my mind around these more smoothly