ABB SPNIS21 Network Interface Module – Reliable INFI-NET connectivity for Symphony/INFI 90 systems

The ABB SPNIS21 is a Network Interface (NIS) module used in Symphony/INFI 90-based DCS architectures to bridge controllers and nodes over the INFI-NET plant network. It typically serves as a drop-in replacement for aging INNIS-series cards, helping teams keep legacy assets online without reworking cabinets or application code. From my experience, when a plant needs to stabilize network comms or restore a redundant A/B channel, swapping to SPNIS21 is often the quickest path to recover.

You might notice that SPNIS21 keeps things straightforward: coaxial INFI-NET ports on the front, backplane communication to the rack, and clear LED status cues for quick diagnostics. In many cases, it’s used in redundant pairs for higher availability, especially on units tied to critical loops or historian gateways.

Order Placement Process and Guarantees

• Warranty: 365 days
• Delivery: 1 week if in stock; no more than one month at the latest
• Payment terms: 50% advance payment, full payment before delivery
• Express options: FedEx, UPS, DHL

One thing I appreciate is the minimal commissioning effort. Teams typically confirm node addressing, cable termination, and redundancy settings, then it’s back in service with a short functional test.

Key Features

• INFI-NET plant network interface – Provides the network bridge between controllers/units and the INFI-NET backbone.
• Redundant channels (A/B) – Typically supports dual coax links to improve availability and allow cable or port maintenance without process interruption.
• Backplane integration – Communicates via the standard Symphony/INFI 90 backplane, avoiding custom wiring changes.
• Status LEDs – Front-panel indicators for RUN/FAIL and TX/RX make it easier to pinpoint network and module states at a glance.
• Legacy-friendly – In many cases used as a direct replacement for INNIS-series cards, helping extend life of installed assets.
• Field-proven form factor – Standard plug-in module design suited for ABB Symphony/INFI 90 module mounting units.

Technical Specifications

Note: Specifications can vary slightly by hardware/firmware revision. If you share the board label or revision code, we can confirm exact details.

Related or Supporting Products

• ABB INNIS21 – Earlier generation NIS; SPNIS21 is commonly used as a replacement in the same role.
• ABB INNIS01 – Legacy NIS version; typically replaced to improve reliability and parts availability.
• ABB SPNPM22 / INNPM22 – Controller/processor modules that often operate with an NIS card on the same node.
• ABB INICT12/13 – Communication/termination components used in INFI 90 networks and cabinets.
• 75 Ω coaxial accessories – Proper terminators and T-connectors for INFI-NET segments to maintain signal integrity.

A maintenance engineer from a power plant told us the SPNIS21 dropped into the slot where an INNIS21 kept flapping links under load; with correct 75 Ω terminations and updated addressing, the nuisance alarms disappeared. It seems to be a common pattern on older networks.

Installation & Maintenance

• Cabinet & environment – Install in a clean, dry 19-inch cabinet with adequate ventilation. Keep ambient within 0–60 °C and avoid vibration and conductive dust.
• Grounding & shielding – Bond cabinet ground properly; use 75 Ω coax with consistent shielding and correct network grounding strategy per plant standard.
• Cabling & termination – Use the specified 75 Ω coax for INFI-NET; verify A/B channel terminators and segment topology before power-up.
• Addressing – Set node address (DIP/switch) to match the configuration database; document changes for the control system backups.
• Safety – De-energize the rack when replacing non-redundant modules. For redundant networks, follow ABB’s live-replacement procedures carefully.
• Routine care – Periodically inspect connectors, re-seat during planned outages, clean dust with ESD-safe methods, and keep firmware notes aligned with the site’s revision control.

Quality & Certifications

• CE marking (typical for ABB industrial control modules)
• UL/cUL recognition (varies by revision)
• Manufactured under ISO 9001 quality systems
• RoHS compliance depending on production date and region
• Supplier warranty: 365 days; manufacturer’s policy may apply for new, unopened units