2020-12-30, 05:11 AM
by default the setting of the pypilot motor controller has both min and max speed set to 100% which means it will only be either on or off. Most lead screws have a lot of friction and therefore are very inefficient at partial speeds so it's better to make small corrections at full speed anyway. People with more efficient drives like ball screws can use variable speeds efficiently, or if they want to reduce noise at the expense of power consumption.
The thing you will have to look for are the slew speed settings which ramp up and down the power even with min speed set to 100% to greatly reduce current spikes. Maybe you just want to set them to the maximum value, or at least increase them.
If you can drive your solidstate relays from an arduino pin (40mA max, recommend only 20mA) then you could use an arduino and drive it that way. Otherwise, the regular controller could either drive the relays or just the solenoids direct, probably I would not use the solid state relays in this case because they aren't needed.
To drive a solenoid typically the voltage needed to hold it on would be less than to turn it on, so special code could be added to make it reduce power consumption for this case... but certainly not a priority for me to implement at this time.
I realize motor.ino is not the most readable, but the function is important. A few have modified it to make it more readable but it changed the functionality for the worse so I have not adopted the changes.
As for disabling current... you could just ground the current sense pin, or if you have the regular controller just set a high max current that will not normally trigger (unless the wiring to the solenoid gets shorted or something)
It would be interesting to hear the results, you may need to tweak other pypilot settings and use different gains to get the best performance. Is there a particular reason for a continuous pump rather than a reversible one? Just because it's already installed? It's pretty clear that reversible pumps are significantly more energy efficient...
The thing you will have to look for are the slew speed settings which ramp up and down the power even with min speed set to 100% to greatly reduce current spikes. Maybe you just want to set them to the maximum value, or at least increase them.
If you can drive your solidstate relays from an arduino pin (40mA max, recommend only 20mA) then you could use an arduino and drive it that way. Otherwise, the regular controller could either drive the relays or just the solenoids direct, probably I would not use the solid state relays in this case because they aren't needed.
To drive a solenoid typically the voltage needed to hold it on would be less than to turn it on, so special code could be added to make it reduce power consumption for this case... but certainly not a priority for me to implement at this time.
I realize motor.ino is not the most readable, but the function is important. A few have modified it to make it more readable but it changed the functionality for the worse so I have not adopted the changes.
As for disabling current... you could just ground the current sense pin, or if you have the regular controller just set a high max current that will not normally trigger (unless the wiring to the solenoid gets shorted or something)
It would be interesting to hear the results, you may need to tweak other pypilot settings and use different gains to get the best performance. Is there a particular reason for a continuous pump rather than a reversible one? Just because it's already installed? It's pretty clear that reversible pumps are significantly more energy efficient...