Post by cullenhall on May 17, 2018 20:39:26 GMT -5
Its not often, however, sometimes we want to watch a movie in the theater during the day and looking at blackout screens I found one can spend quite a bit and not get great curtians especially when I really would want somthing motorized. We decided that we didnt want to spend the money to get a good set of motorized blackout curtains as it was much more affordable to just by an LCD TV to mount behind our projector screen. I found a great deal on a 60" TCL 4k HDR "scratch and dent" with no damage that I can discern for about $300 so that looked to be just the ticket.
This way if one wants to watch during the day they chose to use the LCD TV based activities on Harmony and when they want to use the projector they select the projector based activities on the Harmony. I already had a motorized screen, however, I unhooked the "controller" it came with to minimize the cables I needed to hide and there was nothing behind the screen to see anyway. All that changed when I installed the LCD TV now I need the screen to go up and down.
My first plan of attack was to use IR, the screen came with a simple remote control why wouldnt that work? No luck, the frequency of the IR setup is one that is not compatible with Harmony aparently so IR control of the screen was out. Next was to utilize the 12V trigger from the projector, certainly the controller would accept such an input. No luck there either. The controller had "field" I/O connections but they are for raise, lower or stop and they need to be connected to "dry" contacts as the controller provides power from each of those ports. My next line of thinking was to connect a single pole double throw relay to the 12V trigger of the projector and use either the normally closed connection to make up the "raise" connections on the controller and the normally open connection to make up the "lower" connections. This worked well enough but it did keep applying 120V to the screen in an attempt to raise or lower the screen. The screen has adjustable limit switches so the motor itself would be de-energized when it arrived at its desired position but was a but uneasy about leaving 120V applied to the screen esentailly at all times. The factory controller would drop power after 1 minute or so if you used the provided remote or used the buttons on the side of the controller. I have included some pictures of the controller my screen came with in case anyone is interested.
The engineer in me took over and decided, "heck I design control systems for power plants I can certainly dream up a better way of doing this, not to mention I have an entire UL 508A panel shop at my disposal, lets do this right!"
Enter an extra (older) PLC that I had laying around. It has 8 digital inputs, and 4 relay outputs. Perfect.
I selected a relay that has a 12V coil that can be driven by the 12V trigger on my Epson projector and has double pole double throw contacts (though I only needed one set). The relay will tell the PLC if the projector is on or off and the PLC will take care of lowering or raising the screen based on timers I programmed into the PLC. I added logic so I can manually lower, raise, or stop the screen using the front panel buttons and the display tells you how long it will be till the screen is either raised or lowered or if its not moving the state the screen is in.
I just started wiring it tonight inside a simple control box (see attached picture) so this will be my thread for deploying this controller and any trials and tribulations I have along the way!
If anyone has a similar issue let me know and I can make my PLC program available.
This way if one wants to watch during the day they chose to use the LCD TV based activities on Harmony and when they want to use the projector they select the projector based activities on the Harmony. I already had a motorized screen, however, I unhooked the "controller" it came with to minimize the cables I needed to hide and there was nothing behind the screen to see anyway. All that changed when I installed the LCD TV now I need the screen to go up and down.
My first plan of attack was to use IR, the screen came with a simple remote control why wouldnt that work? No luck, the frequency of the IR setup is one that is not compatible with Harmony aparently so IR control of the screen was out. Next was to utilize the 12V trigger from the projector, certainly the controller would accept such an input. No luck there either. The controller had "field" I/O connections but they are for raise, lower or stop and they need to be connected to "dry" contacts as the controller provides power from each of those ports. My next line of thinking was to connect a single pole double throw relay to the 12V trigger of the projector and use either the normally closed connection to make up the "raise" connections on the controller and the normally open connection to make up the "lower" connections. This worked well enough but it did keep applying 120V to the screen in an attempt to raise or lower the screen. The screen has adjustable limit switches so the motor itself would be de-energized when it arrived at its desired position but was a but uneasy about leaving 120V applied to the screen esentailly at all times. The factory controller would drop power after 1 minute or so if you used the provided remote or used the buttons on the side of the controller. I have included some pictures of the controller my screen came with in case anyone is interested.
The engineer in me took over and decided, "heck I design control systems for power plants I can certainly dream up a better way of doing this, not to mention I have an entire UL 508A panel shop at my disposal, lets do this right!"
Enter an extra (older) PLC that I had laying around. It has 8 digital inputs, and 4 relay outputs. Perfect.
I selected a relay that has a 12V coil that can be driven by the 12V trigger on my Epson projector and has double pole double throw contacts (though I only needed one set). The relay will tell the PLC if the projector is on or off and the PLC will take care of lowering or raising the screen based on timers I programmed into the PLC. I added logic so I can manually lower, raise, or stop the screen using the front panel buttons and the display tells you how long it will be till the screen is either raised or lowered or if its not moving the state the screen is in.
I just started wiring it tonight inside a simple control box (see attached picture) so this will be my thread for deploying this controller and any trials and tribulations I have along the way!
If anyone has a similar issue let me know and I can make my PLC program available.