UR-4DH GE Multilin Digital I/O Module

General Electric UR 4DH Digital I/O Module

Configured for digital input/output execution in UR Series Universal Relay frames, the General Electric UR 4DH (UR 4DH digital I/O module) provides direct physical contact processing for auxiliary control points and inter‑relay signaling. The module supports multiple digital output card types, including Form‑A, Form‑C, latching, fast Form‑C, and SSR variants.

Hardware Specifications

Backplane Bus Communication Velocity Licenses

The UR-4DH follows GE industrial control conventions for deterministic backplane communication. Digital input states and output commands propagate through fixed‑cycle UR bus timing, ensuring predictable state transitions under load. I/O density scaling allows mixed card types without requiring firmware flash compatibility adjustments across UR relay families. Output cards with mechanical latching maintain stable interlocking behavior, while Form‑A cards support activation speeds under typical wet/dry contact conditions.

Frequently Asked Questions

Q: Can the UR‑4DH be hot‑swapped in a UR chassis? A: No. Digital I/O modules require the relay to be de‑energized before insertion or removal to maintain backplane signal integrity.

Q: Does the UR‑4DH support isolated digital inputs? A: Yes. Certain card variants include isolated inputs with auto‑burnish functionality. Isolation type depends on the specific card installed.

Q: Are Form‑A outputs suitable for fast protection schemes? A: Form‑A outputs provide standard activation speeds and are appropriate for typical protective applications. Fast Form‑C or SSR cards should be used when higher‑speed operation is required.

Field Installation Guidelines

• Maintain separation between digital I/O wiring and CT/PT circuits to reduce noise coupling.
• Use shielded cabling for isolated inputs and terminate shields at a single point.
• Verify correct slot placement, as UR modules must match the original module type installed.
• Apply uniform pressure across the module’s connector edge to ensure proper backplane seating.
• When wiring mechanical latching outputs, include arc‑suppression components for inductive loads.