an PI regulator. is for changing values (inputs / outputs).

The I part of the PI reulator will change tho output even when the inputs are constant the same.

If you want a fix value to an analog output then you can take a "Mathematical insrtucting" block

Toeternietoe

an PI regulator. is for changing values (inputs / outputs).

The I part of the PI reulator will change tho output even when the inputs are constant the same.

If you want a fix value to an analog output then you can take a "Mathematical insrtucting" block

 first of all thank you, but I think I could not describe my question very well, I have a sensor that sense process every second  and connected to Analog Input 1 then connected to PV of PI Controller.

my SP is 50 degrees, If temperature goes up or down suddenly, I want it goes back to SP(50) quickly

thanks

ixo65

 

mostafasamurai

first of all thank you, but I think I could not describe my question very well, I have a sensor that sense process every second  and connected to Analog Input 1 then connected to PV of PI Controller.

my SP is 50 degrees, If temperature goes up or down suddenly, I want it goes back to SP(50) quickly

thanks

With the PI controller of the LOGO! can only be adjusted in one direction.

Depending on the control direction, either:
- the control variable is increased when the setpoint is exceeded, depending on the level of the control deviation.
or
- the control variable is increased when the setpoint is lower, depending on the level of the control deviation.

Both types of deviation (lowering and exceeding) can not process by one PI controller, only one of the two, either up-regulation or down-Regulation.

 

 thank you, I searched on logo's help and found this:

Dir = upwards/+ (timing diagram numbers 1 and 3)
If the updated value PV > SP, then the special function reduces the value of AQ.
If the updated value PV < SP, then the special function increases the value of AQ.

if I select +Dir, it is good for my application or not?

can you explain?

thanks

ixo65

No, I can not because I have no more details about your process.
I do not know whether the actual value exceeds the setpoint value and the actual value should be adjusted downwards.
Or whether the actual value falls below the setpoint value and the actual value is to be adjusted upwards.
Or both.

This information must come from you.
You must explain your process more .

 sorry about this, I was wrong.

Exactly, when the actual value exceeds the setpoint value and the actual value should be adjusted downwards and when the actual value falls below the setpoint value and the actual value is to be adjusted upwards.

I need to an Analog Output (0-10) because the electronic board needs to 0-10v

thanks

ixo65

 

mostafasamurai

sorry about this, I was wrong.

Exactly, when the actual value exceeds the setpoint value and the actual value should be adjusted downwards and when the actual value falls below the setpoint value and the actual value is to be adjusted upwards.

I need to an Analog Output (0-10) because the electronic board needs to 0-10v

thanks

This can't be done with the PI controller LOGO! because the output signal is 0-10V.
The PI control can be at 0-10V only one, either up-regulation or down-Regulation. 

 how about use of two PI Controller? is it possible?

what is your opinion?

thanks

ixo65

In attachment a possible solution.

 thanks a lot, I'm checking your program. please see attachment.

for example when operator select 30v for output of power, the electronic board needs to 5v from controller(LOGO), at the welding process if voltage decreases, LOGO must increase Analog Output Value and if voltage increases, LOGO must decrease Analog Output Value. we need a constant voltage.

thank you

ixo65

My opinion:

Forget your idea to solve the problem (welding machine) with a LOGO!.

That's why I had already asked you for details about the process.

 what do you think? is it possible?