pid

can someone here help me out with the setup screen in the pid controle

Can you tell us what the analog input is?
4-20ma or 0-10 vdc? What does it represent, -50to50 deg?

What value does you analog output need to be 4-20ma or 0-10 vdc?

Is the setpoint going to be fixed or will the operators have the ability to change it?
Is there limits for your setpoint if its variable?

the analog input is 0 - 10V -50 - 50 celsius

the output value have to be 0 - 10v

i have panel view c600 there i have to be able to change the set point

siggibald said:

i have panel view c600 there i have to be able to change the set point

Click to expand...

Limit on the setpoint? from what to what?

it have to be able to adjust the setpoint 0°c-20°c

See sample below.

Note changes to ladder 2 to call ladder 3.

Note changes to the analog card's configuration. (Scaled for PID data format)

Tuning parameters will vary of-course with your process.

Your posted program shows a setpoint of 22 deg if this is correct you can change the test for limit instruction.

thanks !! bud when i change from "raw" to "scaled for pid" then i just have incorrect temp value

PD9:1.SPS is that the setpoint witch i can string to panel view

but when i change from "raw" to "scaled for pid" then i just have incorrect temp value

Click to expand...

The PID instruction wants the PV enterd as a 0-16383 value, it is then scaled to your engineering units internally if you setup the PID for set point scaling. see picture. This also allows you to enter the set point as a engineering unit value.

You have the "SCP" instruction that provides you with the temperature in engineering units. If you also configured the "PID" instruction for "scaled setpoint" (see picture, input parameters) Then you can read the PV's value at register "PD9:1.SPV.

I'm not familiar with your PV C600 so not sure if it can poll a PD9:1 register. You may have to move that to a N?:?? or a Floating point data type register so that your PV can poll it.

PD9:1.SPS is the register you write to, that is the PID's setpoint. Again not sure if your PV can read that type of register, you may have to move it to an integer or floating point type data file to read it back to the PV.