The SFA ZPS1 is a single-pump control unit from Elektromotorenwerk GmbH designed for liquid level regulation in wastewater, sump, and drainage applications. It supports multiple sensing methods — 4-20 mA analogue transmitters for continuous level measurement, float switches for discrete level detection, reed switches, and an integrated pressure sensor (0–100/500 mBar) for dynamic pressure-based measurement — selectable through the onboard control program.

How does the 4-20mA level sensing and control work?

The ZPS1 accepts a 4-20 mA transmitter input with a configurable measurement range from 1 to 1250 cm, calibrated via the menu-driven LCD interface. Operators set start and stop levels, turn-on delay (0–180 s), and follow-up/stop delay (0–180 s). The Hand-Stop-Auto operating mode selector on the front panel provides manual override when needed. A programmable pump changeover interval supports dual-pump alternating operation for balanced wear.

What motor protection and monitoring features are included?

Electronic motor current monitoring is adjustable from 0.5 to 14 A — currents below 0.5 A trigger a fault load alarm, while setting to 0 A disables monitoring. Phase error detection, thermal fault monitoring (TH1/TH2 control loops), and runtime monitoring (0–300 s) protect the pump motor. The controller logs faults to a 32-entry protocol memory and supports a programmable maintenance interval counter (0–365 days) with automatic service reminders. An internal acoustic alarm and potential-free collective fault contact provide local and remote fault indication.