Multi Controller Communication question

[binzer]

Is this fresh or salt?

Even without automation two of everything on 2 separate circuits is a good idea. That is the place to start.

This is a good idea but depends on the room, most split the overhead lights and outlets, if the room is being built then the option exists. I know that I would like to do that also for my tanks, and computers but since the whole place was finished I doubt I can pull it off.

Size the heater so if one fails to shut off it will not cook the fish. If one fails to come on the other it enough to keep the fish alive if not happy. When you have the controllers installed I would turn the heaters up to where they do not turn off and use the uC to switch them.

I agree , but most of the better heaters ( I have jagers ) have a good temp control built in. They usually say to stagger 2 heaters, one at the temp you want and one a couple of degrees lower in case of an ' off ' failure. If the heater fails ' on ' is where the uC monitoring would come to play and be used for ' overtemp ' and maybe sense which heater is on at the time and disable it. As always there is more monitoring to do than controlling, as was said before it can get very complex real fast if you consider all the factors, still it's nice to caht about and toss out ideas.

Size the filtration so that either one can handle the entire load. In normal operation each will have about half the bacteria needed. If one fails the other will rapidly grow enough bacteria to handle the additional load.

A wet/dry and 2 pumps may cut down on cost, a spare pump is cheaper than a spare filter unless you already have one.

In addition to the filtration I suggest you keep an airstone in the tank to keep the water moving should both filters fail. The tank walls are covered with bacteria and as long as the water is moving it will do some biological filtration. Also with 2 filters you can alternate filter cleaning.

Never thought of that.

A battery operated air pump to keep the water moving when power fails is a good idea. Next best thing to using battery backup on the filters.

All of this will help keep the aquarium alive with or witout monitoring.

He should be making a list, picking priority, equipment list ( have & need )

EDIT:
Everything need to be on a GFI

I agree, but most of the pumps, filters, lights, etc are all 2 wire polarized, the GFI's measure leakage current thru the ground leg to trip, correct??

 

[binzer]

For more then two units talking you want to go with RS485 (half duplex). RS422 (full duplex) is most often for two units talking to each other as with RS232.

For now I would work on the backup power and redundant systems. The PS and redundant systems will provide more protection then monitoring because they work even if you are not there or ignore them.

Then add a single Ethernet connected controler with RS485 to talk with other controlers when they are added.

If you do that there is no need to figure out the protocol at this time.

For reasons I can not reacall I did not choose the CAN protocol. It was intended for automotive use.

I mentioned the 'CAN' modules because they can be configured to only report when you are outside the set parameters, cutting down on extra talking / overhead on the network. We have machines that use ' interbus ' , kinda cool concept but an overkill for this.

EDIT: Since then inexpensive uC's with larger memories and more speed have shown up. Size is less of an issue. At this point I would look at what tools (network monitor etc) and maybe a good support group.

 

[binzer]

Redundant circuits is important with or without UPS. Should anything develop a short the UPS can not power its circuit. A 2nd circuit with duplicate equipment is the only thing that will save the fish.

I did not mean to say monitoring was unimportant. But less so with redundant systems. A monitoring system will tell you when then system failed. The redundant system will keep the fish alive in spite of the failure.

I think the monitoring part should be first ( after redundant equipment ), and leave spare I/O for the control part.

Microchip now has a 1 chip ethernet solution. Maybe a subnet just for the control system.

If it was all ethernet you could control/monitor it thru a web interface and add something to alert you. Oh the options.

 

[jbarnaby2000]

I think the monitoring part should be first ( after redundant equipment ), and leave spare I/O for the control part.



If it was all ethernet you could control/monitor it thru a web interface and add something to alert you. Oh the options.

I know...they are truly endless huh... and I do agree with you on the monitoring part first too...

 

[3v0]

My comments are indented in quoted text.

This is a good idea but depends on the room, most split the overhead lights and outlets, if the room is being built then the option exists. I know that I would like to do that also for my tanks, and computers but since the whole place was finished I doubt I can pull it off.

A few pumps and heater do not draw much. You could tie the 2nd circuit to the lights. If that is not going to work split the existing circuit in the fishroom and add a breaker and GFI on each sub circuit. Make sure the new breakers (total?) are rated for less then the one in the breaker box.​

I agree , but most of the better heaters ( I have jagers ) have a good temp control built in. They usually say to stagger 2 heaters, one at the temp you want and one a couple of degrees lower in case of an ' off ' failure. If the heater fails ' on ' is where the uC monitoring would come to play and be used for ' overtemp ' and maybe sense which heater is on at the time and disable it. As always there is more monitoring to do than controlling, as was said before it can get very complex real fast if you consider all the factors, still it's nice to caht about and toss out ideas.

You can do that. But since you already have the temp sensors in place there is no need for expensive heaters. Just crank em up to close the contacts and let the uC run a relay. I have a number of jagers and they die too.​

A wet/dry and 2 pumps may cut down on cost, a spare pump is cheaper than a spare filter unless you already have one.

Good idea. If you used two full sized pumps you could alternate them.​

I agree, but most of the pumps, filters, lights, etc are all 2 wire polarized, the GFI's measure leakage current thru the ground leg to trip, correct??

A lot of people think that but GFI does not use the ground leg. It check the hot against the neutral. If it is not equal it trips.​

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[3v0]

Redundancy is the first step to a good system. (That and automatic water changing)

After that it is up to you I do not see much distinction between monitoring and IO/control. To me they are parts of the same system.

This is an extreme example. lets say you fish will get sick or die if they go below 65 for some period of time. It is winter and your thermostat is setback to 60 while you are at work. When your heater fails your system sends a message over the network and tells the furnace to up the setting. Same thing if you have a wicked wind from the wrong direction and the heaters can not keep up.

No end in sight...

 

[jbarnaby2000]

Redundancy is the first step to a good system. (That and automatic water changing)

After that it is up to you I do not see much distinction between monitoring and IO/control. To me they are parts of the same system.

This is an extreme example. lets say you fish will get sick or die if they go below 65 for some period of time. It is winter and your thermostat is setback to 60 while you are at work. When your heater fails your system sends a message over the network and tells the furnace to up the setting. Same thing if you have a wicked wind from the wrong direction and the heaters can not keep up.

No end in sight...

Thats true...but here in New Mexico we dont get that cold...or really that hot either...and I hope to be putting this system on a 300+ gallon tank so to do that kind of temp change would take many hours... I do plan on dual 20Amp GFCI circuits, as for dual pumps...well I hope to have that as well. As for heating elements that is always a given to have redunancy there. For the amount of water, there will probably be close to 1000watts of heater, and also many pumps as well...both for the closed loop systems that just move water inside the tank, and then the filter pumps, and then there will be other pumps for the Protien skimmers as well...

Thx for all the input...boy I have a lot of planning now...

 

[binzer]

Thats true...but here in New Mexico we dont get that cold...or really that hot either...and I hope to be putting this system on a 300+ gallon tank so to do that kind of temp change would take many hours... I do plan on dual 20Amp GFCI circuits, as for dual pumps...well I hope to have that as well. As for heating elements that is always a given to have redunancy there. For the amount of water, there will probably be close to 1000watts of heater, and also many pumps as well...both for the closed loop systems that just move water inside the tank, and then the filter pumps, and then there will be other pumps for the Protien skimmers as well...

Thx for all the input...boy I have a lot of planning now...

What type of heater are you using now, 300 gal is a big tank?

 

[jbarnaby2000]

What type of heater are you using now, 300 gal is a big tank?

I dont have the tank yet... but I will be using in line heating I think, I have found some that are titanium 500W units.