Board Adds Pump Sleep Mode

Why? Because standard PID control may, depending on system demand, allow a pump to operate at undesirably low speeds for prolonged periods of time. This can cause mechanical problems with certain pump types, and in general is a wasteful use of energy, because most pumps do not generate significant flow or head at low speeds. The IPU-PSM allows for the specification of a lower limit on inverter output frequency. Should the PID function call for a frequency below that limit for a user-defined period of time, the inverter will go to “sleep,” meaning the inverter output will shut off and the pump stops. If system pressure drops below a defined level for a specified period of time, the inverter will “wake” and resume normal PID pressure regulation.

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