what is the definition of nominal value for a process parameter. Is it the same as setpoint???

 

A nominal value is one which should be approximately correct but may need to be adjusted to account for real world factors.

For example, let's say you have a feeder machine that feeds out material until a certain weight is achieved. Let's assume that because of the speed of the process the machine tends to overshoot, or dispense too much material. If the overshoot is consistent, you can adjust for this by adjusting the setpoint entered by the use downwards slightly to account for this.

In this case the weight setpoint entered by the user would be the nominal setpoint (i.e. the raw weight with no adjustments) and the internal setpoint is the real setpoint (because it factors in the details of the process).

Hope that helped...