Some serial port / LCD questions.

[jaredfine]

I'm building an alarm system and I'm considering using the serial LCD's as the HUD for the alarm activity, hallway moniters basically.

First I was curious as to what the maximum run would be. The controller will most likely be in the basement and it'd be great to get it to work to potentially a third floor.

My second question is, would it be possible to daisychain the displays or is this a major no-no? The communcation is essencially one way, basically pushing out display codes to the com port.

Thanks in advance!

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[CF Tech]

Does each display need to display the same information? If so, it might be possible to connect multiple CFA-632 or CFA-634 modules.

As far as maximum run, we were messing around with a CFA-634 and a roll of CAT-5 one day, and we got it to run at about 800 feet. This is certainly not something we could guarantee, but it would probably work for you at typical household distances.

 

[jaredfine]

Thats great to hear about the long run, because that was exactly what I was thinking of doing, getting a serial to cat5 converter and using cat5 (probally plunem) in the walls.

Each LCD would display exactly the same information at the same time. Also the content woudl only be updated every second or so.

I suppose as a follow up, do you suppose I could also deliver the +5v through the cat5 to the LCD also? If so, how many LCDs would I be confortabally able to connect at once to a single ATX powersupply and serial port?

Oh I'm planning on using the backlit 634 displays. Thanks so much for your help!

 

[CF Tech]

You could try a setup like this, but I think the 5v would drop too much over the long distance if you are only using the CAT 5 (certainly if you are trying to run the backlight). Maybe run the +5 & ground over a separate heavier connection.

Be sure to do the whole thing with a "dry run" to make sure the long cables and multi-drop work, we only tried one so I do not know if there was any margin for error.

 

[jaredfine]

Thanks for the handy link!