Reef Central Online Community - View Single Post - My Neptune Apex web interface compatible DIY reef controller

d0ughb0y · 10/26/2013, 06:59 PM

I just got the WP-25 I ordered. Delivered in 2 days.

I opened up the controller to check the circuit.
The output control signal is a 3.9 khz pwm signal, 256us period.
It controls the output in 8 steps, starting from 256us for 100% then decrements 16us for each step until it reaches 128us or 50% duty cycle. W2 and W3 are like sawtooth waveform, with W2 incrementing up in 6 steps and down 6 steps, while W3 increments in 6 steps and down in 8 steps from 50% to 100% and back down to 50%. The knob controls the frequency of the sawtooth wave.

this shows the W1 mode low (or pump off), is 1us on to 255us off.

at the lowest time setting (fully counter clockwise) in W1 mode, pump is off for 0.24seconds and on for 0.24seconds. The white block you see is actually comprised of tons of the 1us pulses shown above.

The output pwm is passed through a resistor /capacitor to convert the pulses to an analog signal.

I think it should be possible to read the control signal using the arduino analog read, and then for Pass-Thru, simply do a digital write to a PWM output pin. I'm not sure if feeding PWM to the pump will work, but it should be easy enough to add a resistor/capacitor to convert it to analog if needed.

I can then program the controller to override the control signal.

The modes on the stock controller seems to work fine. It does not go down below 50% though, except for W1 mode which pulses between 0% and 100%, but the maximum can be controlled via S1 S2 and S3. S1 is 100%, S2 is more like 80% and S3 is more like 60% (the documentation says its 100%, 75% and 50%).

I can see the need to override the stock controller signal say if you got a WP-40 and find it too strong for your tank, as there is currently no way to lower the maximum flow. The S1 S2 S3 flow control only works with W1 mode. I don't think it is proper to be reducing the 24V power to reduce the pump flow as others are doing in the wp-40 thread.

I can implement override to reduce flow to a user controllable value. I don't really see the need to re-invent the different modes that already works fine on the stock controller. I think one cool feature would be to plot in the pump flow level say for the last 3 minutes, which is simply the value of the analog read of the control signal.

So far, I think the WP-25 is a very nice pump, and probably should be a standard issue for any reef tank.

10/26/2013, 06:59 PM	#67
d0ughb0y Registered Member Join Date: Mar 2008 Location: sf bay area Posts: 5,165	I just got the WP-25 I ordered. Delivered in 2 days. I opened up the controller to check the circuit. The output control signal is a 3.9 khz pwm signal, 256us period. It controls the output in 8 steps, starting from 256us for 100% then decrements 16us for each step until it reaches 128us or 50% duty cycle. W2 and W3 are like sawtooth waveform, with W2 incrementing up in 6 steps and down 6 steps, while W3 increments in 6 steps and down in 8 steps from 50% to 100% and back down to 50%. The knob controls the frequency of the sawtooth wave. this shows the W1 mode low (or pump off), is 1us on to 255us off. at the lowest time setting (fully counter clockwise) in W1 mode, pump is off for 0.24seconds and on for 0.24seconds. The white block you see is actually comprised of tons of the 1us pulses shown above. The output pwm is passed through a resistor /capacitor to convert the pulses to an analog signal. I think it should be possible to read the control signal using the arduino analog read, and then for Pass-Thru, simply do a digital write to a PWM output pin. I'm not sure if feeding PWM to the pump will work, but it should be easy enough to add a resistor/capacitor to convert it to analog if needed. I can then program the controller to override the control signal. The modes on the stock controller seems to work fine. It does not go down below 50% though, except for W1 mode which pulses between 0% and 100%, but the maximum can be controlled via S1 S2 and S3. S1 is 100%, S2 is more like 80% and S3 is more like 60% (the documentation says its 100%, 75% and 50%). I can see the need to override the stock controller signal say if you got a WP-40 and find it too strong for your tank, as there is currently no way to lower the maximum flow. The S1 S2 S3 flow control only works with W1 mode. I don't think it is proper to be reducing the 24V power to reduce the pump flow as others are doing in the wp-40 thread. I can implement override to reduce flow to a user controllable value. I don't really see the need to re-invent the different modes that already works fine on the stock controller. I think one cool feature would be to plot in the pump flow level say for the last 3 minutes, which is simply the value of the analog read of the control signal. So far, I think the WP-25 is a very nice pump, and probably should be a standard issue for any reef tank. Last edited by d0ughb0y; 08/03/2017 at 11:25 PM.