nickelflippr said:Either way, a PIC with MSSP should a requirement of the master controller. The MSSP would allow you the master-multiple slave controller relationship that you are looking for? This of course is dependent on a fairly local distance requirement.
nickelflippr said:For long distance sensors, the Dallas one-wire bus might make sense. I think a mix of bus types is inevitable, because they all have their pros and cons.
Do you know that distance requirement?? is it 1 inch or 10 foot or 100 meters?? The local of the controllers from one another I am thinking will not be more than 10 to 15 feet. Do you think MSSP would be a good protocol to use?
I will have those sensors talking to thier slave controllers and then the slave controllers will relay that information back to the main hub controller. Does that make sense in what I am trying to do??
nickelflippr said:The distance for the I2C bus is dependent on the pullup resistors and the capicitance of the wire used. Best to visit the I2C protocol by Philips and check past posts on this forum. Using the built in hardware (as opposed to software) of a PIC is always a good thing if available.
nickelflippr said:Doesn't make sense to use all the slave controllers, when one master controller could do the whole job easily.
jbarnaby2000 said:I agree on keeping it simple...and right now this is to monitor one tank...with the option of monitoring more. But the main thing I want to do is make it as modular as possible.
And yes I know, you can go really crazy/overboard with this type of system, and I would really like to make it redundant...or at least make it an option, so I will look at putting that into the design...
As for the RS484 networks though.... Does that pretty much work like RS232 but with a further distance capability?? or can they be connected in parallel, or series, and have some kind of addressing scheme to determine who is talking?
I am looking at have the slave modules hook to a master module sort of in a hub/spoke type design like a star network. The main controllers will most definitely have some ethernet connectivity like you suggest though, wether it will be wired or wireless I have not decided that yet.
binzer said:You might want to check this out: **broken link removed** check ADN004
You are thinking of RS422. RS485 is half duplex and only requires 2 wires and ground. It is a physical standard and does not indicate what protocol is used.binzer said:It's a master / slave type setup and I think everybody has an address, master sends commands and slave responds. I believe it's a balanced line type cabling with 2 wires for tx and 2 for rx, should have a ground also.
It will be a Salt tank3v0 said:Is this fresh or salt?
I was thinking the same Idea here... My power control modules I am thinking will be able to be dual sourced (House and UPS power) and then I will be able to hopefully monitor if pumps/Heaters/Lights fail and be able to have backups online...at least that is the plan3v0 said:Even without automation two of everything on 2 separate circuits is a good idea. That is the place to start.
jbarnaby2000 said:See I dont even think the redundant power is such a big thing though. Since I can just run the entire system on one or many UPS's and have the UPS do the power monitoring thing though.
But monitoring the tank I think is pretty important, since I would really like to monitor temps, and other water quality characteristics like PH and ORP and NH2 and NH3 would be really wonderful to monitor and track on a regular basis.
Heck at this point I may just make all the modules ethernet capable...that way I can use very common wiring standards and protocols too...
Thx for all the great ideas...
3v0 said: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.
3v0 said:Microchip now has a 1 chip ethernet solution. Maybe a subnet just for the control system.
jbarnaby2000 said:I see where you are going with the redundancy...and yes I totally agree there.
Aren't there even a couple of PIC18's that have ethernet on the CPU?? At this point that maybe the way to go...as for its own subnet....great idea...that way it would keep that traffic localized to that system. Great Idea...Thx...
I guess you have thought of they type of system a lot too huh.....
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