PLC & Electrical

The Brains

An Allen Bradley Micrologix 1000 is installed and programmed to run the reef. A 24 hour clock is set up, and the on and off times for the lighting are controlled off of this timer, with outputs controlling relays that power the ballasts. The main return pump and skimmer pump are run off of controlled outputs that switch relays to power the outlets they are plugged into. I have 8 switches wired into the PLC for overriding the lighting and pumps, and for specialty features such as my feed switch. If I press the feed switch the main return pump and skimmer pump will power off for the amount of time I have programmed into the PLC, and then turn back on. This makes for a pretty convenient setup. I will soon be adding the float switch to the sump area for the auto top off, which I have already built into the program. All of the electrical is tucked up in the "rafters" of the stand.

Picture of the ballasts and 4 of the PLC controlled outlets. You can see the relays in front of the outlets that the PLC control to power the outlets. A small fan blowing in and an exhaust port keep them cool.

This picture shows the PLC and the red and black switches. It may not be noticeable in the photos but the PLC and ballasts are protected by being mounted under acrylic. Each plug is number with the output number of the PLC.

The outlet without the cover plate is wired direct and is used for the heaters. The 12vdc power supply for the 5 cooling fans is now plugged into one of the controlled outlets. They come on one hour before the lighting, and continue one hour after.

This is kind of an overall view of the electrical looking into the top of the stand. The switches are easily reached with either of the doors opened slightly. Their are unused outlets for future expansion of the system if needed.