1. Session 4 – Static Characteristics
Control Theory
Session 4 –
Static Characteristics

2. The static process characteristic
Tells us A
Tells us B
A- What the possible process equilibria are and is as such not dependent on properties of the control loop the process might be part of.
B- What the possible process equilibria are given the entire control loop – this characteristic depends also on the parameters of the controller.
[Default]
[MC Any]
[MC All]

3. Given a P controller, the point (r,b)
Is always part of the control charaxcteristic.
Is only part of the control characteristic when the bias is chosen well.
[Default]
[MC Any]
[MC All]

4. Which is true for a control system with P controller?
Static process and control characteristic always cross in (r,b).
Static process and control characteristic cross in (r,b) when the bias is calculated based on that value of r.
Static process and control characteristic cross in (r,b) when the bias is calculated based on that value of r AND based on the value of d that was used to find the static process characteristic.
[Default]
[MC Any]
[MC All]

5. Now we draw 2 possible control characteristics (blackboard)
Both look fine
Nr. 1 is not a very appropriate P controller
Nr. 2 is not a very appropriate P controller
[Default]
[MC Any]
[MC All]

6. (See blackboard). The steady state error is given by
[Default]
[MC Any]
[MC All]

7. Group Task
Process:
Sensor and actuator:
Controller:

8. Group Task
Try to find out what the steady state error is when Tref = 32 °C and Tin changes from 40 °C to 70 °C.
Both use graphs and calculations.