Plc Diy

[easttn]

Anyone out there ever use PLC's to drive all your electrical equipment?

[coralreefengr]

Not to sound dumb, but I don't know what PLC is.

[easttn]

PLC is an acronym for Programmable Logic Controller. The device I have has the capability of monitoring 16 inputs and controlling 12 output relays (or whatever) @ 12 or 24VDC. I started learning about these things last night and already have the software up and running on my PC to program the controller.

The plan is to finish the programming on Friday and build a relay board this weekend. There will be 1 24 VDC relay for each of the electrical components , and a couple of input relays for conditional controls. The list below describe what the relays will be controlling:

1 controls 2 400W radiums - on from 11AM to 9PM
1 controls 2 Actinics - on from 10AM to 11AM & 9pm to 10PM
3 control 3 Power heads each on for 55 secs. on a rotational basis
1 controls calicum reactor (redundant)
1 controls heater - on at 77 off at 78 via thermocouple on input (redundant)
1 controls topoff for DI water addition
1 controls shutoff of main pump
a. Turnoff at 6:30PM, fish feed then on at 7PM,
b. Emergency off if show tank water level rises too high
1 controls skimmer off at 6:30PM on at 9:30PM
Last one controls a doser that I do not own yet.

[easttn]

I successfully got the PLC programmed today at work ;) . I have all the logic entered as stated in the first part of the thread. It was really not too hard. I sat down with a copy of Step7-Micro/WIN 32 and got my PC to talk to the PLC's CPU, via the PPI cable, and it was off to the races. Hardest part was figuring out how to program the controller to determine the time of day. From then on it was logic statements to compare the time of day to when I program the controller to turn the different outputs on and off. This in turn controls all lights, temp, additions, topoff.... The next step is building the relay board. I'll post pictures when done. Any one out there any good with GUI interfaces? If we made a GUI for the program and all you would need to enter from a pc is the time of day this would be huge.