GE UR4LA Digital Input/Output Module

Configured for protective relay integration in Universal Relay (UR) platforms, the GE Multilin UR4LA (UR4LA Digital I/O Module) provides direct physical/electrical execution of isolated input sensing and high-speed discrete output control for power system protection.

Hardware Specifications

Industrial Control and Network Characteristics

• Backplane bus communication velocity: The module utilizes the high-speed Universal Relay backplane bus to transmit I/O status to the main processing unit. This velocity is necessary for maintaining deterministic execution of protection schemes, ensuring that sub-cycle response times are achieved during fault events.
• Profinet / EtherNet/IP deterministic networks: When the host UR relay is configured for networked communication, the UR4LA module acts as a high-speed data source, translating discrete field inputs into status packets compatible with SCADA and industrial automation networks.
• I/O density scaling: The 8-input/4-output configuration provides localized signal consolidation, enabling high-density protection logic to be executed within a single relay chassis without requiring external auxiliary interposing relays.
• Firmware flash compatibility: The hardware supports firmware updates via the UR platform interface, ensuring ongoing alignment with protection algorithm refinements and security standards required for critical utility infrastructure.

Frequently Asked Questions

Q: Does the UR4LA support hot-swapping under normal load conditions?

A: Yes, the UR4LA is designed for hot-swap operations within the Universal Relay chassis. The backplane design ensures that insertion or extraction does not impact the operation of adjacent modules or the host relay's protective functions.

Q: Are the digital inputs polarity-sensitive?

A: The inputs are optically isolated to provide noise immunity. Ensure that the 48 Vdc (30–60 Vdc range) source is connected with the correct polarity as defined in the wiring diagram to ensure proper activation of the internal optical couplers.

Field Installation Guidelines

• Mounting: Insert the module into the designated slot of the UR relay chassis. Use the integrated locking levers to ensure the backplane connector is fully seated, which is mandatory for reliable communication and I/O signal continuity.
• Grounding: The UR chassis provides the primary ground path. Ensure the relay chassis itself is bonded to the substation or cabinet earth bus using a low-impedance connection to protect against surge transients and electromagnetic interference (EMI).
• Wiring: Route digital input and output wiring through dedicated shielded signal paths. Keep these lines separated from high-voltage AC circuits and secondary CT/PT lines by at least 150 mm to prevent inductive noise injection into the relay protection scheme.