Different methods of controlling motorized screens, lifts, curtains and blinds
When an AV system contains a projector to be controlled by a Biamp control system, there are often a drop-down screen to be controlled as well. There are many types of drop-down screens out there and they can be controlled in many different ways depending on the manufacturer and model.
One of the most typical questions that we get in support is "How do I connect this screen to my Biamp controller?". That is why we have written this article to guide you in selecting the correct method of control, based on the screen that you have at hand.
High Voltage
Two directional mains powered screens (100-240VAC)
A very typical application is the screens that has 4x mains wires coming from the screen.
- Earth
- Neutral
- Up
- Down
These types of screens are easiest controlled by a Biamp Switching Relay-2 or 4 using the screen connector. The screen connector makes sure that only the 'Up' or 'Down' receives power and not both at the same time. This might lead to damaging the electric motor.
Here is how to add a the screen functionality on a Switching Relay-4 screen connector in Project Designer. The screen connector uses Relay 1 and 2.
Mains triggered screens (100-240VAC)
Some screens drop down when you apply a mains voltage to an input and retracts again when you remove the mains power from the input.
Here is how to add a Switching Relay-4 with a mains triggered screen connected to Relay 1.
Low Voltage controlled screens:
Contact Closure controlled screens
Many screens are connected to mains via a wall outlet, and then have a low voltage contact-closure interface for control. That basically means that you can "short-circuit" pre-defined wires to make the screen retract or roll out. Check the screen manual for details.
Here is an example of a screen with contact-closure inputs and how to connect it using the GPIO's on an Echo Plus controller.
There is also an option to use relays instead of GPIO. Here is an example of how to connect it using the screen connector in a Switching Relay-2 or 4.
Low voltage triggered screens (Typically 3-24VDC)
Many screens have an option to control the up and down functionality using a voltage sensor. In a typical application the screen retracts if voltage is between 0 - 3VDC and between 3 - 12VDC it rolls out. Make sure to check the manual of the screen at hand, for the range of the voltage sensor. It might vary from different screen manufacturers.
Here is an example of how a Low voltage triggered screen (3-12VDC) can be controlled using the GPIO's with an Echo Plus controller with the Biamp included 12V PSU.
Please note: On a Biamp GPIO, the voltage should not exceed 24VDC and current should not exceed 500mA.
On some control systems it is not an option to use the Biamp PSU like i.e. a Uniform or a Tango powered by PoE. In those cases you can use an external power supply to provide the 3-12V required by the screen. Here is an example of a Tango controlling a screen using an external PSU and a relay to control it.
Data Signal:
IR remote controlled screens
This solution should always be the last resort in case the other options in this article is not possible with the screen at hand. Reason being that an IR blaster can fall off over time or be affected by various sources of light pollution such as PIR from alarm systems, sunlight etc. So you can never really be sure that the command is received, and the system is in the state that you want it to be. Here is an example of a screen being controlled by IR from an Echo Plus controller. The IR commands are either listed in the manual or they can be learned in Device Editor using the remote that comes with the screen. Have a look at this article on how to learn IR codes in Device Editor.
Data controlled screens (Serial, IP)
Some screens can also be controlled via data sent to a screen control interface using either serial data (RS232/RS485) or IP data (TCP/UDP). In the below example showing a RS232 interface connected to a Echo Plus. The commands required for operating the screen was found in the screen manual and a driver can quickly be made using Device Editor. Have a look at this article on how to get started making drivers in Device Editor.
