Flow Rate

[viscoelastic]

Using a shaft encoder atop a flow meter. In the High Speed Inputs section of the hardware one of the MI's can be set for frequency.  Is there any issues with simply linearizing the frequency to say L/min? In tests it seems to work, but I am wondering if there is any reasons not to do it that way?

Thanks

[kratmel]

2 hours ago, viscoelastic said:

there is any reasons not to do it that way?

In my opinion, this is the most accurate method of all possible in the PLC.

This is because a hardware pulse counter and a hardware timer are used to obtain the resulting frequency. All other methods using ladder code, timers and even interrupts have an error related to program execution time.

That's why I use this method and recommend it to you.

[viscoelastic]

18 minutes ago, kratmel said:

In my opinion, this is the most accurate method of all possible in the PLC

Kratmel, Thank you. I thought the same, but sometimes when something seems too easy, there is a problem.

[kratmel]

On one of the machines for metal laser cutting, I was asked to make a two-channel "speedometer" for coolant flow meters.

All that was needed was an indication of two frequencies.

Ironically this was my first Vision PLC installation in which I did not write a single line of ladder code .... I only created one HMI display

[viscoelastic]

On 5/13/2022 at 5:45 PM, kratmel said:

Ironically this was my first Vision PLC installation in which I did not write a single line of ladder code

That may be true, but I am sure everyone was still impressed.

As it is said: In the land of the blind, the one eyed man is king. That day, I am sure you were the king. 🤣