PWM Pump Control Board

[FunkedOut]

The control board for the PWM pump has disappeared from the BrewPi store. Is it coming back? Or gone for good?

[FunkedOut]

Haven’t seen any traffic here, so I’ll bump this one up.
And ask a related question.
Is there any way to set a profile to drive the % on a PWM?
Looking to start a pump slow at the beginning of a mash, then gradually speed things up.
Thanks.

[Bob_Steers]

Not directly, but it can be done with some creative use of a mock sensor.

If you have a sensor -> setpoint -> PID -> PWM chain using a mock sensor, you can use the profile to control the setpoint/sensor “error”.

A PID with ti=0 and td=0 will have predictable output % based on Kp and temperature error.

If you set Kp to 1, output will match input error.
For example, with a setpoint setting of 20, and a sensor value of 0, output will be 20%.

[FunkedOut]

How slow can the pump be run? 10%?
What does that equate to in L/min?

[Bob_Steers]

The minimum for meaningful output is 15%. At that point, the displacement is “very little”. We can’t assign a more exact value to that.

[alexsunny123]

@Bob_Steers

Not directly, but it can be done with some creative use of a mock sensor.

If you have a sensor → setpoint → PID → PWM chain using a mock sensor, you can use the profile to control the setpoint/sensor “error”.

A PID with ti=0 and td=0 will have predictable output % based on Kp and temperature error.

If you set Kp to 1, output will match input error.
For example, with a setpoint setting of 20, and a sensor value of 0, output will be 20%.

thanks for the awesome information.

[alexsunny123]

@alexsunny123

@Bob_Steers

Not directly, but it can be done with some creative use of a mock sensor.

If you have a sensor → setpoint → PID → PWM chain using a mock sensor, you can use the profile to control the setpoint/sensor “error”.

A PID with ti=0 and td=0 will have predictable output % based on Kp and temperature error.

If you set Kp to 1, output will match input error
For example, with a setpoint setting of 20, and a sensor value of 0, output will be 20%.

thanks for the awesome information.

thanks my issue has been fixed.

[Elco]

The fastpwm block also has a slow start setting that will do transitions slowly. If you set it to a very long value, you can do a slow ramp on every transition.