Control Systems Flashcards
What is the function of a control system?
Control systems are used to align the AV solution to the client’s current requirements, according to their desired use.
What kind of functions could be managed by a control system?
Turning on or off screens or projectors Changing lighting levels Opening or closing blinds or curtains Adjusting volume or audio controls Selecting inputs for playback Switching on ancillary devices, mood lighting, background music etc.
What is a macro?
Macros are used to perform a number of related and coordinated functions with a single user input.
For example, just selecting a laptop input on a touchscreen in a meeting room might also turn on the screens, amplifiers and interactive whiteboard surround, dim the room lighting, lower the blinds for confidentiality and raise a desk mounted cubby containing the laptop input cables.
What input devices can a client use to control their AV solution?
The most common client inputs are switch panels, touch screens and web based or app based control panels. These devices communicate the client’s requirements to the central control processor.
What is the aim of good client interface design?
The aim is to provide the necessary control with a simple, reliable, intuitive interface. The more the customer has to learn in order to use the interface, the more that can go wrong and the less some bill be inclined to make proper use of the solution.
What is a GUI?
A Graphical User Interface (GUI) is the screen, and the buttons, fields, switches etc on it that the client uses to control their AV solution.
Good GUI design gets maximum value from the solution with simple to use controls.
What is the difference between a unidirectional and a bidirectional control system?
Unidirectional systems are where the control system simply issues commands to the external devices, and some devices only support this feature.
A generally better approach is to use a bidirectional control system where the end devices acknowledge the commands and feed back, so that the control system always knows the status of the overall solution.
What is the difference between contact closure and variable voltage control units?
Contact closure devices simply have two states, or or off. They can be used to confirm that a curtain has reached the end of the track, or a room partition is closed, allowing the system to reconfigure the audio.
Variable voltage control systems are often used with dimmable lights and camera controls.
Name two technologies for wireless control and what are their respective limitations?
Infra red (IR) or radio frequency (RF). IR needs line of sight and can also be significantly affected by high ambient or very direct light. RF controls are susceptible to radio interference and need careful planning to avoid issues.
What are the main cabling standards for control systems?
RS-232 is by far the most common, but is unbalanced and therefore only suitable for relatively short cable runs, about 60 feet (20m).
RS-422 improves on this using a balanced four-wire cable to run up to 4,000 feet (or 1,200m).
RS-485 is similar in distance to RS-422 but can support up to 32 or more devices and multiple transmitters.
How has AV integration with IT networks changed the future of control systems?
With the ever closer integration into IT networks, a lot of control systems are now being run via Ethernet connections, which significantly increases the system’s capabilities and potential future features.
