Hi all,

I would like to find a solution to adjust pump speed ( using 0-10v ) based on the input from a flow meter. these aquarium pumps don't have a very steady speed and I need to be able to adjust the speed so not to create waterfall noises ( that's an aquarium term about the noise on an overflow box).

So if the speed goes down, i need to increase output voltage, if speed goes up vice versa.

All that against of a preset value ( can be pumpspeed or outgoing voltage).

I have included the LSC file and a jpeg in a zip file.

Left part is the flow meter part

Righ part is the outgoing voltage control ( incl. starting value).

Thanks for the help

Sounds like a nice little project.

So what is your question?

the flowmeter is a hall sensor based deviced, china sourced.

I benchmarked the I11 and final result against the LPH display device that came with the flowmeter. So thats fine. 

I use now the manual part from the right to manually in- or decrease the output voltage ( analog value) to the pump, I then read the LPH in NAQ8  and adjust manually. 

I'm looking to automate the manual part. 

If NAQ8 > 3600: decrease voltage over AQ1

if NAQ8 < 3600: increase voltage over AQ1

Voltage value is 0 to 9999, best is to adjust with increments of 100.

Thanks.

"A analog output works only in 0-1000 units = 0,00 to 10,00 V in steps of 0,01 V, if you the voltage output of the modul."

--> fine for me. Understood.

kruemi

So what is your question?

 well, to be able to throtlle the pumpspeed ( 0-10v) based on the LPH input against a presetted LPH value.

Hello degregoriis;

Your description of the project makes sense for some sort of closed-loop control (PID), and the LOGO! has a PI instruction that could help you.

Study the entries in the LOGO! Soft Comfort online help for the PI instruction, and have a look at the following application example for a basis to your own project:

PI Controller with LOGO! for Simple Applications - Optimum Motor Speed Control (Set 23)

https://support.industry.siemens.com/cs/ww/en/view/23753479

“A PI controller in the LOGO! logic module adjusts the pressure by varying the motor speed depending on the pressure that is being measured. The pressure of the cooling water system is thus kept constant, independent from the number of consumers. The cooling performance is optimized and failures caused by a shortfall of pressure are prevented.”

Hope this helps,

Daniel Chartier

@IXO65 :

thanks for this great help. I had to change a liitle bit to make it work and t is working fine.

However, due to a built in start up delay in the pump controller, i need to wait 30 secs before starting the control by the PLC. Where would it be best to put a delay in ? Thanks again for your help.

Learning a lot !