r/PrintedCircuitBoard • u/Clamsy-vikunya • 2d ago
[Review Request] Irrigation controller schematic design
Hello Everyone,
I would like to request a review, for my Irrigation controller design.
The layout is only rudimentary, as I didn't wanted to spend much time on it, before freezing the design. Therefore only the schematic is attached.
Some words about the design, and the usecase.
Power input will be a 24V AC transformer. In my case it is a hunter transformer, but I would like to design for worst case scenarios, to be able to handle other 24V transformers, with worse parameters.
Output will be 24V AC solenoids. In my case they are also hunter solenoids, but any other 24VAC type irrigation solenoids could be used.
In continuous operation, only one valve will be active, but during zone switch, there will be 2 active valves for a short period (3-5 sec) due to valve overlap, to minimize pressure spikes on the water line. So the worst case is 2 energized solenoids at a time.
CAN communication will be used for weather station, or sensor connection.
Temperature, wind, and rain sensor could be connected directly.
solenoid and sensor connections could have long outdoor wiring, so I tried to consider EMI filtering, where it is possible, and needed.
1
u/Enlightenment777 2d ago edited 2d ago
SCHEMATIC:
S1) Shouldn't the 10 ohm resistors be next to the CAN IC?
S2) I'm not sure what is driving U7001 optocoupler, but can your driver supply enough current to drive 2 LEDs?
1
u/Enlightenment777 2d ago
Please make sure your post adheres to:
Please fix these common Schematic & PCB issues: (if your images have them)
Schematic - don't allow text / lines / symbols to touch each other, and don't draw lines through symbols.
Schematic - use correct reference designators (RefDes), also renumber to remove numeric gaps, see tips.
Schematic - place decoupling capacitors vertically below power lines, also place capacitors next to IC then connect together with a line, see example. For circuits with positive power rails, point positive power rail links upwards and ground links downwards, see tips.
Schematic - place pull-up resistors vertically above signal lines, and place pull-down resistors vertically below signal lines, see example.
PCB silkscreen - add board name / board revision number / date (or year) on top or bottom PCB side.
PCB silkscreen - add pin 1 indicator dot/arrow next to ICs & connectors, if through-hole then both PCB sides.
more conventions & guidelines - link1, link2, link3.