Product Description:

The EL1722 is a digital input EtherCAT terminal produced by Beckhoff within the EL EtherCAT Terminals series. It captures mains-level AC signals and transfers their logic state onto an EtherCAT fieldbus, allowing PLCs to supervise limit switches, contactors, or indicator lamps without discrete wiring back to the cabinet. Designed for quick snap-in assembly, it occupies a single slot on the DIN rail and draws system power from neighboring terminals.

The terminal presents 2 digital input channels, each accepting a nominal voltage of 120/230 V AC, so the module can be wired directly to mains-level sensors. Internally, a 10 ms input filter suppresses contact bounce, and the response time for a transition from active to inactive is also 10 ms. The front end uses two-wire connection technology, simplifying field installation because line and neutral are sufficient for each point. Logic status is transferred to the backplane through the EtherCAT E-bus, where the terminal typically consumes 55 mA. The absence of distributed clocks means sampling occurs asynchronously, which is acceptable for non-time-critical power detection tasks. For isolation, adjacent inputs can withstand up to 230 V AC.

During operation, the terminal draws only 6 mA per active channel from the field side, placing minimal load on upstream circuitry. Electrical robustness complies with overvoltage category II, and functional integrity is maintained up to an altitude of 2000 m. The housing meets protection class IP20, so it must be mounted inside a cabinet but allows tool-free engagement on a 35 mm DIN rail. No power contacts are routed through the module, keeping control and load circuits separated. The specified isolation between inputs supports the safe monitoring of building service signals and other mains indications. Its compact terminal format also allows it to be installed beside compatible EtherCAT modules without requiring a separate fieldbus coupler for each monitored circuit.