ABB IMDSI22 Discrete Input Module for INFI 90 – Reliable 24 VDC field signal acquisition

The ABB IMDSI22 is a discrete (digital) input module used widely in INFI 90/Symphony systems to bring 24 VDC field contacts into the DCS with stable, noise-immune performance. From my experience, it’s the kind of card you choose when you need high channel density, steady diagnostics, and predictable behavior in utility, oil & gas, and process manufacturing plants. You might notice that it slots into the standard INFI 90 I/O rack and connects to a termination unit, which keeps field wiring clean and service-friendly.

Typical applications include pump start/stop status, limit switches, valve end-position feedback, motor protection relays, MCC status, and interlocks. One thing I appreciate is the straightforward LED indication per channel—it seems simple, but maintenance teams often prefer that quick visual check during commissioning and fault finding.

Order Placement Process and Guarantees

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

Key Features

• 24 VDC discrete inputs – Designed for common plant contact signals (proximity, dry contact via wetting, relay outputs).
• High channel density – Typically a multi-channel card (often up to 32 inputs) to reduce cabinet footprint and wiring complexity.
• Opto-isolation and noise immunity – Helps withstand electrical noise in MCC rooms and long cable runs, improving reliability.
• Front-panel status LEDs – Quick indication of channel state and module health for faster troubleshooting.
• INFI 90 backplane integration – Seamless with ABB controllers and engineering tools used on Symphony/INFI 90 systems.
• Termination unit wiring – Field signals land on the TU; the module connects via ribbon cable, which typically speeds up replacements.
• Input filtering – Debounce/filtering functions commonly used to handle mechanical contact chatter.

Technical Specifications

Note: Channel count, isolation ratings, and exact consumption may vary by module revision and termination unit; if you share the TU model or a photo of the nameplate, we can confirm the precise figures.

Related or Supporting Products

• ABB IMDSO14 – Digital output module (24 VDC), complementary to IMDSI22 for driving solenoids and interposing relays.
• ABB IMASI23 – Analog input module, commonly paired in mixed I/O cabinets; higher-resolution AI for transmitters.
• ABB IMMFP12 / IMMFP13 – Multifunction processor modules for INFI 90; host control logic and manage I/O scanning.
• ABB INICT01 – Network interface for plant/host communications; often used to bridge INFI 90 to higher-level systems.
• ABB INNIS01 – Network interface module for peer-to-peer/plant network integration in many installations.
• Typical termination units (TU), e.g., NTDI/NTST series – Field wiring boards matched to the discrete input module and voltage.

Installation & Maintenance

• Cabinet & environment – Install in an ABB INFI 90 rack within a clean, dry control cabinet. Maintain ventilation and keep ambient within the specified temperature range.
• Wiring practice – Route discrete signal wiring separately from power cables. Use proper shielding and grounding for long runs; add surge protection for outdoor devices.
• Termination units – Land all field wires on the correct TU; verify channel mapping and polarity before applying power. Ribbon cables should be secured and strain-relieved.
• ESD & safety – Follow ESD handling; isolate field power before inserting/removing ribbon connectors. Module insertion/removal should follow plant MOC and lockout procedures.
• Commissioning – Check LED status per channel, validate scan state in the engineering tool, and confirm debounce settings for mechanical contacts.
• Routine maintenance – Periodically inspect terminal tightness, clean dust from the card guides, and check for any loose ribbon connections. Firmware isn’t usually updated on the I/O card itself; configuration resides in the controller.

A maintenance engineer told us they typically keep one spare IMDSI22 and one spare ribbon cable per cabinet. It’s not that they fail often—in many cases they run for years—but spares cut recovery time dramatically when a field wiring fault takes out a channel group.

Quality & Certifications

• Manufacturer: ABB, industrial-grade design for INFI 90/Symphony systems
• Certifications: Typically CE compliant (EMC/Low Voltage); many units are UL Recognized. RoHS compliance depends on production year/revision.
• Warranty: 365 days (hardware)