alec:
The LT1074 is good for 5 Amps. Do you really think it could handle 2 pumps STARTING at the same time?
The other issue is your "FEED switch" which really doesn't look like a switch in the diagram. The DOT is hard to see.
Might we want both voltages to be adjustable somewhat?
60 uH is close to 68 uH, so you expecting that to be salvaged from the OEM controller. Lower L's are better to assure oscillation from a design point of view. But we aren't sure what the current rating of the inductors are in the OEM controller.
The method chosen for changing the feed voltage might not be compatible with using transistors as as the switching elements. e.g. With feed, it makes more sense, I think, to drive that with a timer. i.e. push button, feed fish, walk away, You have a timed feed mode and it automatically recovers. You might need to think ahead a little bit and think what might happen when an automatic feeder is introduced, not saying that it will be.
(alarm) The alarm needs a tiny bit of help. You need to include a switch labeled Alarm and with labels ON and Silenced. A LED should always indicate the alarm state independent of a silenced buzzer.
(What pump?) You did say that the controller would know what pump has trouble. This is missing. The ULN2004 would work nicely here.
ALARM, PUMP PAIR 1 (at U3c), PUMP PAIR 2 (at U3d), ALARM pump #1, ALARM pump #2, ALARM pump #3, ALARM pump #4.
Yuk, unfortunately an extra pin isn't available for a LOGIC probe. There is an 8 output version of the chip, the ULN2804.
I'd put a 3 pin header at pump 1, pump 2 , pump 3 and pump 4 which will allow disconnection of the drivers. e.g.
OFF ON using 3 pins * * *. The left most is on, the right most is off. There is no connection to the left pin. The right most pin just goes in series with the output. You may not need this if there is an easy way of disconnecting the pump. Suppose, you determine that the pumps need cleaning, but you don't have time to fix it. So, you just disable the pump by moving the jumper.
Comments on the motor driver circuit.
The terminals used for the current sense resistor (0.22 ohm resistor ?) should be brought out to a terminal block where it is easy to probe and so should the voltage to the motor be easily probe-able. These are key troubleshooting points. Assuming the voltage is constant and you measured the voltage across the 0.22 ohm resistor which is proportional to motor current, you have a base line. Bearing friction would show up as more current.
This is also an argument for the jumper. You could re-route signals to turn on a motor with a wire jumper which is another key troubleshooting point. You could even use a 6x2 header with positions of (ON OFF Automatic) for the U3 jumper.
A power/logic ground connection is not shown on the schematic. It doesn't make sense to ground the low voltage side of the system in a marine environment. It does make sense to protective ground any metal cases though.
Salty:
The max output of the regulator will be ~two volts less than the input voltage. So, 20 V hopefully will result in about 18 V.
Alec:
You did real good, but were're not out of the woods yet. I may have a source for the inductors if the ones from the OEM supply are not suitable. 5A ones may be harder to find than 3Amp ones. Who knows.
Your entitled to take the ideas as a grain of salt, but later I could be saying "I told you so".
Remember I think in terms of modular, maintainable and serviceable. So, again thinking serviceable again, one can think about using links to BYPASS/INSERT the secondary regulator or it could be a separate board altogether and you just pull the board and add a jumper.
Don't mind me, I always have stuff to say. Alec, you turned this around really quick.
The LT1074 is good for 5 Amps. Do you really think it could handle 2 pumps STARTING at the same time?
The other issue is your "FEED switch" which really doesn't look like a switch in the diagram. The DOT is hard to see.
Might we want both voltages to be adjustable somewhat?
60 uH is close to 68 uH, so you expecting that to be salvaged from the OEM controller. Lower L's are better to assure oscillation from a design point of view. But we aren't sure what the current rating of the inductors are in the OEM controller.
The method chosen for changing the feed voltage might not be compatible with using transistors as as the switching elements. e.g. With feed, it makes more sense, I think, to drive that with a timer. i.e. push button, feed fish, walk away, You have a timed feed mode and it automatically recovers. You might need to think ahead a little bit and think what might happen when an automatic feeder is introduced, not saying that it will be.
(alarm) The alarm needs a tiny bit of help. You need to include a switch labeled Alarm and with labels ON and Silenced. A LED should always indicate the alarm state independent of a silenced buzzer.
(What pump?) You did say that the controller would know what pump has trouble. This is missing. The ULN2004 would work nicely here.
ALARM, PUMP PAIR 1 (at U3c), PUMP PAIR 2 (at U3d), ALARM pump #1, ALARM pump #2, ALARM pump #3, ALARM pump #4.
Yuk, unfortunately an extra pin isn't available for a LOGIC probe. There is an 8 output version of the chip, the ULN2804.
I'd put a 3 pin header at pump 1, pump 2 , pump 3 and pump 4 which will allow disconnection of the drivers. e.g.
OFF ON using 3 pins * * *. The left most is on, the right most is off. There is no connection to the left pin. The right most pin just goes in series with the output. You may not need this if there is an easy way of disconnecting the pump. Suppose, you determine that the pumps need cleaning, but you don't have time to fix it. So, you just disable the pump by moving the jumper.
Comments on the motor driver circuit.
The terminals used for the current sense resistor (0.22 ohm resistor ?) should be brought out to a terminal block where it is easy to probe and so should the voltage to the motor be easily probe-able. These are key troubleshooting points. Assuming the voltage is constant and you measured the voltage across the 0.22 ohm resistor which is proportional to motor current, you have a base line. Bearing friction would show up as more current.
This is also an argument for the jumper. You could re-route signals to turn on a motor with a wire jumper which is another key troubleshooting point. You could even use a 6x2 header with positions of (ON OFF Automatic) for the U3 jumper.
A power/logic ground connection is not shown on the schematic. It doesn't make sense to ground the low voltage side of the system in a marine environment. It does make sense to protective ground any metal cases though.
Salty:
The max output of the regulator will be ~two volts less than the input voltage. So, 20 V hopefully will result in about 18 V.
Alec:
You did real good, but were're not out of the woods yet. I may have a source for the inductors if the ones from the OEM supply are not suitable. 5A ones may be harder to find than 3Amp ones. Who knows.
Your entitled to take the ideas as a grain of salt, but later I could be saying "I told you so".
Remember I think in terms of modular, maintainable and serviceable. So, again thinking serviceable again, one can think about using links to BYPASS/INSERT the secondary regulator or it could be a separate board altogether and you just pull the board and add a jumper.
Don't mind me, I always have stuff to say. Alec, you turned this around really quick.