Questions regarding pH control and charts with sockets

[TehBrainz]

Hello!

I'm using my pH probe on my PF4 to control a socket that opens and closes a valve for my CO2 scrubber. My nominal is set to 8.25 with hysteresis at 0.1 (pretty tight IMO, but I'm testing the set up as I just hooked it up last week). As I understand, this should set controlling range to 8.20-8.30. My socket that has my valve is set up to the pH probe and controlling downwards.

What I've witnessed is that the socket opens the valve at 8.3 to divert past the scrubber (correct action) and lower the pH. The socket closes the valve, though, at 8.25 to start increasing pH instead of at 8.20 as I thought it should. Any thoughts? Should I just reduce my nominal to 8.20?

Also, I would really like to chart out the status of the socket. Besides looking at the pH chart, I don't know how often the valve is opening or closing based on the PowerBar status. It would be great to have this option so I know how much the valve is actuating. PH can be affected by many variables so a rise and fall might not be directly a result of my scrubbing. Maybe have the chart function based on change of status instead of measurement interval like the probes?

I've got some screenshots attached for the first issue.

 

[Lasse]

Also, I would really like to chart out the status of the socket.

There is a workaround of this that I use in order to know how long time my heater is running, P4 has 32 doser functions - I have configure pump 29 to record how long time my heater is running

Configure like this

Record dosage, set the flow rate to 1 ml/min, set container tp 30000 and set the pump to react to switch channel (the one that control your valve (in my case its S19 that control my heater. If you have 1 ml/min - you will be able to see how long time its running - see below

The graph is from 17:00 yesterday to 17:00 today. You can see that the heater is going in 2 minutes (ml) periods and total time for this day is 192 minutes (ml)

Sincerely Lasse

 

[TehBrainz]

There is a workaround of this that I use in order to know how long time my heater is running, P4 has 32 doser functions - I have configure pump 29 to record how long time my heater is running

This looks like it'll work great for my need. I will give it a try when I get back home this evening.

Thank you Lasse

 

[ingchr1]

Hello!

I'm using my pH probe on my PF4 to control a socket that opens and closes a valve for my CO2 scrubber. My nominal is set to 8.25 with hysteresis at 0.1 (pretty tight IMO, but I'm testing the set up as I just hooked it up last week). As I understand, this should set controlling range to 8.20-8.30. My socket that has my valve is set up to the pH probe and controlling downwards.

What I've witnessed is that the socket opens the valve at 8.3 to divert past the scrubber (correct action) and lower the pH. The socket closes the valve, though, at 8.25 to start increasing pH instead of at 8.20 as I thought it should. Any thoughts? Should I just reduce my nominal to 8.20?...

That's the way the hysteresis works on sensors, except temperature.

I would set nominal to 8.2 with a 0.2 hysteresis.

From the P4 Programming Guide:

GCC screenshot:

 

[TehBrainz]

That's the way the hysteresis works on sensors, except temperature.

I would set nominal to 8.2 with a 0.2 hysteresis.

From the P4 Programming Guide:

GCC screenshot:

Thanks for the confirmation. After I posted and looked at the data that's what I started thinking and then adjusted the nominal and hysteresis as you mentioned. For some reason I had it in my head that it was +/- hysteresis. Maybe I'm confusing it with how the alarms equation works.

 

[Lasse]

On more idea - you can use the controller mode two position controller - and in that case it works with an hysterisis and the real value will oscillate as described above

However I want my heater to work as steady as possible - therefore I use a controller mode pulse variable and in my case - max pulse 4 min and a fixed paus of 30 sec. In this mode the time the heater is connected is max 4 min but it will be shorter when you are close to the nominal value. After the on period (max 4 min) it will go off for 30 sek and see what the temperature is again - and calculate a new on period. The on period and the off period is depended on the system and have to be figured out for each aquarium design,

When my temperature is totally depended of the heater - I get a very stable temp in my aquarium. As seen below during march this year - it was very stable around 24.9 degree C. sample period 5 min

Sincerely Lasse

 

[TehBrainz]

So I set up the doser to how your post described. Really simple and I realized quickly that I needed a second "doser" that was connected to the same socket, but set to inverted. This way I could see when the valve is opened (power on) and off (power off). Works great so far. Once I have more data I'll make a post with some requests for the GHL team regarding this tracking ability.

Anywho, I now have a question with thr data for the doser. If I have it set to "dose" for 1ml/min, what does the duration correspond with?

Out of two examples below, the first is close to the dosage so I thought that is what it was related to. But the second shows a big difference from 152 ml/min (~2.5 hours) and duration of ~41 mins.




Brian

 

[Lasse]

If you set the calibration to 1 ml/min - dose of 1 ml is equal with 1 min - at least in my app that is configured to the metric system

The dose show this - 118 sec = 1,97 min - close enough for me

The small staple 19 sec = 0,32 ml - close enough for me

Sincerely Lasse

 

[TehBrainz]

If you set the calibration to 1 ml/min - dose of 1 ml is equal with 1 min - at least in my app that is configured to the metric system

The dose show this - 118 sec = 1,97 min - close enough for me

The small staple 19 sec = 0,32 ml - close enough for me

Sincerely Lasse

Ahhh so I didn't hit the "calibrate pump" button when I went through setting up the doser to 1ml/min. That could be it. I'm also using metric system for dosing pumps.

The problem I am seeing is the duration time is nowhere close for me (e.g. 2457s =/ 150ml, actually closer to 41ml).

 

[Lasse]

I do not do it either hit the calibration button - I just type in 1 ml and use the slow speed.

Sincerely Lasse

 

[TehBrainz]

I do not do it either hit the calibration button - I just type in 1 ml and use the slow speed.

Sincerely Lasse

Yea I didn't think it would matter since it is a virtual doser, but thought I'd try regardless.

I just received a new update and wanted to illustrate the point again. The doser "amount" is nearly spot on with the doser duration way off. I can definitely be ok with the "amount", it's just strange they don't seem to match even in the slightest. I've even seen a few negative duration times, which is odd.

On another note...Is there a way to change the color of the two doser bars? The blue and violet are rather similar!

 

[Macca_75]

Not out of the box, but I love to dabble in tech. I bought a Raspberry Pi, installed InfluxDb and Grafana and wrote a simple script. It polls some custom pages on my Profilx3 and basically returns all the token values every minute (think probes, sockets, pump voltages, lights, Digital/Analogue inputs, Dosing pump stuff, etc. 99% of what the Profilux does. Then you can graph the data however you want (for your example I have green/red inidcators when the each heater is on (1 is setup as a heater, the other as a substrate heater - the second only comes on if the first can't keep up). Very customisable but my display is like this (you can search any period of time with accuracy of 1 minute)

It's all actually really easy to do if thats your thing. All up cost was about AU$50 for a second hand Raspberry PI3B

How does this help you? You can overlay anything with anything else (on the same time scale) - such as a sockets status (On/Off) against a pH probe. From memory you can also get the "status" of the probe (ie. is it controlling up or down??)