Description
Key Technical Specifications
| Parameter | Detail |
|---|---|
| Model | DSSR122 |
| Part Number | 48990001-NK |
| Manufacturer | ABB |
| Product Type | Solid-State Relay (SSR) Digital Output Module |
| System Platform | ABB Bailey INFI 90 / Harmony |
| Installation | Rack-mounted plug-in card |
| Logic Power | Backplane powered (typical 5 VDC from rack) |
| Field Load Supply | Commonly 24 VDC (depends on wiring scheme) |
| Output Type | SSR digital outputs, optically isolated |
| Operating Temperature | 0 to +55 °C |
| Communication | Backplane interface only (no external serial/Ethernet port on module front) |
| HS Code | 8537.10 (Boards/panels for electric control, ≤1000 V) |
Product Introduction
Replacing a failed output card in a Bailey INFI 90 rack is one of those moments where you need the exact right part — not something “close enough.” The ABB DSSR122 (part number 48990001-NK) is a solid-state relay (SSR) digital output module designed for ABB’s Bailey INFI 90 and Harmony rack-mounted I/O systems. It plugs directly into the backplane of a standard INFI 90/Harmony cabinet and provides optically isolated discrete output channels for switching field loads.
Solid-state relay outputs eliminate the mechanical contact wear that plagues traditional relay output cards. In continuous-duty applications — pump permissives, solenoid drivers, lamp stacks, valve actuators — SSR outputs deliver silent switching, faster response times, and longer service life with zero contact bounce. The DSSR122 draws its logic power from the rack backplane (typically 5 VDC), while field-side load power is supplied externally, commonly at 24 VDC. Front-panel status LEDs (revision-dependent) provide at-a-glance diagnostics for each output channel.
QA/QC Transparency SOP
If you are sourcing this from a surplus supplier, here is what a competent vendor should verify before shipping:
- Intake & Origin Verification — Confirm the model “DSSR122” and part number “48990001-NK” are legible on the module label. Check for physical damage: bent connector pins, cracked housing, burnt traces, or corrosion on the backplane edge connector. Cross-reference any date codes or revision markings.
- Visual & Mechanical Inspection — Verify the card edge connector is intact with no missing or pushed-back pins. Confirm the module seats properly in a compatible INFI 90/Harmony rack slot without binding. Check that mounting hardware (if applicable) is present.
- Live Functional Testing — Seat the module in a powered INFI 90/Harmony test rack. Verify the module powers up from the backplane without fault indicators. Command each output channel from the controller and confirm the corresponding status LED responds. Measure output voltage at the terminal block under no-load and loaded conditions.
- Electrical Parameter Tests — Using a multimeter or megger, verify isolation resistance between field-side outputs and logic-side circuits. Check for short circuits between adjacent output channels. Confirm output switching response time falls within expected parameters.
- Final QC & Anti-Static Packaging — Photograph the module label and connector condition. Log test results with date and technician ID. Package in an anti-static bag with foam support to protect the backplane connector pins during transit.
Field Engineer Gotchas
- Misclassified Listings — Multiple surplus sellers list this same part number as a “power module,” “processor module,” or “safety relay.” If a listing describes OSSD outputs, SIL 3 ratings, or ARM processors, that is not this module. Trust the part number and the INFI 90/Harmony platform association, not the seller’s description.
- Backplane Compatibility — This card is designed for the Bailey INFI 90 / Harmony backplane. It will not work in ABB AC800M, S800 I/O, or Advant OCS racks. Verify your rack platform before ordering.
- Field Power Wiring — The module draws logic power from the backplane, but field load power must be wired separately. Missing or reversed field power is the most common reason a “new” output module appears dead on the bench. Check your wiring diagram.
- Output Revision Differences — Front-panel LED count and labeling vary by hardware revision. Do not assume a specific number of output channels based solely on photos from a different revision. Confirm channel count against your system configuration documentation.
- ESD Sensitivity — Like all solid-state output modules, the DSSR122 is sensitive to electrostatic discharge. Handle with proper ESD precautions during installation. A careless touch to the backplane pins can kill the output drivers.
ABB DSSR122 48990001-NK
Application Scenarios
- Power Generation — Turbine Auxiliary Switching: INFI 90 systems in fossil and combined-cycle power plants use SSR output modules like the DSSR122 to control turbine auxiliary equipment — lube oil pumps, cooling fans, and breaker permissives — where silent, wear-free switching reduces maintenance intervals.
- Oil & Gas — ESD and Valve Actuation: In process safety-adjacent applications, modules provide discrete output signals to valve actuators and burner management system interfaces within the INFI 90 architecture.
- Chemical Processing — Interlock and Alarm Signaling: Batch chemical reactors and continuous process lines use SSR outputs to drive alarm stacks, interlock relays, and motor control contactors from the DCS rack.
- Water & Wastewater — Pump Station Permissives: Municipal pump stations running legacy INFI 90 controllers use these modules to provide on/off commands to pump contactors and panel indication lamps.
Note: No verified real-world case study specific to the 48990001-NK was found in available sources. The scenarios above reflect typical deployment contexts for ABB Bailey INFI 90 SSR output modules.
FAQ
It is a solid-state relay (SSR) digital output module for the ABB Bailey INFI 90 / Harmony rack-mounted I/O platform. It provides optically isolated discrete outputs for switching field loads.
Why do some sellers call it a “power module” or “processor”?
Because surplus listing quality is inconsistent. Multiple sellers copy-paste generic descriptions or misidentify the module type. The “DSSR” prefix in ABB’s naming convention points to solid-state relay output. Trust the platform association (INFI 90/Harmony) and the part number, not the seller’s title.
What rack platforms is this compatible with?
ABB Bailey INFI 90 and Harmony rack systems. It is not compatible with ABB AC800M, S800 I/O, or other ABB controller families.
What voltage does it need?
Logic power comes from the rack backplane (typically 5 VDC). Field-side load power is wired externally, commonly 24 VDC. The exact field voltage depends on your wiring scheme and load requirements.
Is this part still manufactured?
The Bailey INFI 90 platform is a legacy system. This module is available through surplus and aftermarket channels. New OEM supply may be limited or unavailable — confirm with your ABB representative.
How do I verify the channel count on my unit?
Channel count can vary by hardware revision. Check the module label for revision codes and cross-reference against your INFI 90 system configuration database or hardware manual. Do not rely on photos from other revisions.
Can I hot-swap this module in a live rack?
Verify with your INFI 90 system documentation. Hot-swap capability depends on the specific rack configuration, node controller firmware, and whether the slot supports live insertion. Pulling or inserting I/O cards in a powered rack without proper procedure can damage the backplane or adjacent modules.
