PLC Recommendation for Lighted Dance Floor

LEDs aren't likely to give you the lumens you want (I haven't checked lately, so I could be wrong: check). Fluorescents can be difficult to turn on promptly or with predictable delay. I think you will find incandescents most satisfactory. With a given technology, the lower the voltage, the higher the current for the same delivered power.

You should control each light independently and program the patterns. You may want more than one lamp in at least some squares so you can vary the colors they show.

A PC with appropriate digital I/O card(s) and a sound card is sufficient hardware, but you need to program it yourself.

For a sampling of what's available, check

There are plenty of other vendors.

Jerry

Retro-styling then? I used to run a mobile disco myself so know this stuff reasonably well.

Stick to AC lighting. If you want low levels 40W lamps will suffice under a glass floor. If you need it much brighter then consider 100W lamps. All you will need to switch these is a zero-crossing detector and a range of Optically Isolated Triac switches. The LED of the opto-isolators can be wired as an 8*8 matrix and controlled with two eight bit latches from the processor or logic you are using to set the pattern. You can even get into varying the brightness by delaying the switch-on of the lamps a bit. I would certainly include some mains side filtering to keep the noise levels down into the supply side.

There are plenty of SBC's out there including the "Stamp's" and other units that would be capable enough for this job. No need to spend out that much money on a PLC.

A PC is definitely overkill for the project but as it is to hand you could do something out of the printer/parallel port as regards driving enough latches at the appropriate timing. Quite simple really.

The above is probably about £5 to £10 ($7 to $15) per channel depending on power and filtration components used (in self build anyway).

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How do you turn on more than one lamp without also turning on phantoms? I don't know how to do that with a matrix. Matrix keyboards aren't easily adapted to n-key rollover.

Jerry

Have a look to the IO modules with a RS232/RS422 based communication for PCs ...

Armin

Once the Triac has been triggered they usually continue to conduct until the AC phase voltage descends to a point where conduction cannot be sustained. You just need to ensure good level of gate voltage to switch it on, which it will do in quite a short period of time.

If you want several on at once you power up a row, bring on the ones on that row that are required, then select the next row and do that group, and so on. Repeat the pulse patterns for each selected lamp at each half cycle. This sort of thing can be accomplished very close to zero-switching point when the AC voltage is rising. Delay further to diminish brightness of the lamp.

I see that; thanks. essentially, you trigger one at a time sequentially, and latch the trigger with the triac itself. That needs to be done twice a cycle -- positive and negative halves -- for each "on" lamp and is certainly a very low-cost approach. For a one-off, I would be inclined to latch one bit per lamp, and greatly simplify the software that needs to be written. Version two, if there is one, could replace the latched bits with a matrix and the line-locked interrupt routine to drive it. The light-sequencing part of the program would change only in the addresses of the latched bits. Instead of being output lines, they become the table used by the line-locked driver.

It's the classic trade between cost and simplicity. For a one-off, I lean toward simplicity. Especially with other people's money!

Jerry

Which is what I thought the OP had indicated he was after even though he had enquired about which PLC to use.

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Considering that I did the logic part in TTL chips when I was doing the gear for my own disco set-up quite a few years back now. That approach proved to be a lot simpler and less expensive than other approaches we could have taken at the time. If I had had a PC or SBC available I would have used that as the logic and implemented the logic in software. Our lamps were a hung aloft from a frame we erected at each gig. It certainly set the right sort of mood. I used the same Triac modules for a dimmer unit as well.

You built a lot of circuitry that I presumptuously assumed that the OP, a self-described "computer guy; not an electro-mechanical guy" would rather avoid. I believe that 64 digital I/O lines driving optically coupled 60-watt triac modules as a plug-in to a PC he already has would be enough cheaper than the PLC he had contemplated to make him happy.

Jerry

I did say it was quite a number of years ago. It was back in the era before PC's and a computer was a significantly large peice of equipment. Heck, I have a board that was the ferrite-CORE memroy for one of those systems in my collection of old computer bits. I was not suggesting the OP go that route nowadays. The year I did it was 1973. There is a significanlty larger family of TTL type parts available these days. The opto-isolators were quite interesting too.

Go with the BarioNet device from Barix.

If you are in the U.S., you can buy this from It is an intelligent programmable Ethernet controller for less than $300. It has a built-in web server and a bunch of built-in inputs & outputs. Plus you can buy extension relay modules for a low cost to add more

5-amp relays. (should work fine for your lights) You could program a bunch of different sequences and then switch between them with an input or from a web page, etc.

Thanks for everyone's help! I think this is exactly what I'm looking for.

Brian

bomber snipped-for-privacy@yahoo.com wrote:

outputs.