Control system Flashcards
Provide at least three examples of services provided by building control systems.
Safety (hazard identification (riskidentifiering) and mitigating measures implementation (mildrande ptgärder), air quality)
Security (unauthaurized access)
Comfort (thermal and visual)
Energy Monitoring and fault detection and prediction
What are the characteristics of an efficient system according to classic control theory?
An efficient and ideal control system is one that drives the controlled variable to the desired state (reaches setpoint with little or no offset), does so in as short a settling time as possible, with as little overshoot as possible and in the most efficient/optimal way as possible.
Name at least five obstacles to designing an efficient control system.
System time lags (tidsfördröjning i systemet)
- Transfer lag (tiden för systemet att svara på input, delay for system to react)
- Transport lag (the delay when transporting data)
Sensor
- Location (where the sensor is placed)
- Bias
- Drift
- Uncertainty (how good accuracy (tillförlitlifhet) the sensor have)
- Time constant
- Hysteresis (jitter)
How are the terms “state” and “state space” defined by Modern Control Theory?
State: A state refers to a snapshot in time of a system describing its behaviour with a minimum set of variables.
State space: describes all the possible states that a system can attain
List and describe the key issues that Modern Control Theory concerns itself with.
Observability
To understand the internal states in the system by understanding the data we get from our sensor data
Controllability
It means given a specific external input we can push/drive the system to any desired state within our state-space.
Stability
To reach our desired state (steady state) and remain in that state even if different variables change, not occiliate.
Describe three Building Management System control levels commonly found in the built environment.
Field level: where all the physical sensors, controlled devices live
Automation level: where the controller is implemented
Management level: is where the supervisory control and logging takes place
