Product Core Brief
- Model: IMASI23
- Brand: ABB
- Series: Harmony / Infi90 legacy HR rack analog input family, predecessor to SPASI23
- Core Function: Convert multi-type field analog sensor signals to digital values for Symphony DCS controllers via ModuleBus backplane
- Product Type: Single-width hot-swappable HR rack plug-in analog input PCB
- Key Specs: 16 independent channels | 24-bit dedicated per-channel A/D | Built-in cold junction compensationCondition: New Original (New Surplus) | Factory Sealed; EOL legacy hardware, OEM support available through 2032
Key Technical Specifications
| Parameter | Value |
|---|---|
| Compatible Hardware | Symphony Harmony/Infi90 HR racks, paired with SPBRC410 CPU; incompatible with AC800M, UNITROL, Freelance DCS platforms |
| Supported Field Signals | TC (B/E/J/K/N/R/S/T), Pt100/Pt1000 RTD, ±20mV, 0/4–20mA, ±10VDC analog voltage |
| A/D Resolution & Architecture | 24-bit dedicated converter per channel, no shared multiplexer lag |
| Galvanic Isolation | 1500 VAC channel-to-logic isolation barrier |
| Cold Junction Compensation | Onboard precision CJC circuit, factory calibrated ±0.1°C TC accuracy |
| Full Rack Scan Time | 180 ms for all 16 input channels |
| Backplane Power Draw | 500 mA @ 5 VDC rail, total 6.2 W full channel load |
| Hot Swap Rating | HR rack certified hot-swap; parallel CMA198 power supplies maintain rack operation during swap |
| Termination Hardware Requirement | Matched NTAI06 field termination unit for sensor wiring breakout |
| Operating Ambient Temp | 0 °C to +60 °C full rated precision; linear accuracy derate above 60 °C |
| Storage Temperature | -40 °C to +70 °C, 5–95% RH non-condensing |
| Mechanical Size | 28 mm W × 185 mm H × 128 mm D single HR slot; 0.77 kg weight |
| Compliance | CE, UL, RoHS, IEC 61000-6-2 Class A industrial EMC |
Product Introduction
This legacy analog input PCB is built exclusively for older Harmony/Infi90 Symphony DCS cabinets to capture temperature, pressure, flow, and level sensor signals across boiler and turbine plant assets. Each channel carries independent signal conditioning to eliminate cross-talk between mixed sensor types.Its dedicated 24-bit per-channel converters remove the measurement skew common on older shared-mux IMASI03 and IMASI13 cards. Integrated cold junction circuitry eliminates external TC transmitters, cutting cabinet wiring count and reducing nuisance temperature drift alarms in high-EMI turbine hall environments.
QA & Testing SOP (Transparency Building)
- Incoming Inspection: Cross serial numbers against ABB Symphony legacy OEM trace databases. Inspect gold HR backplane edge connector for oxidation, six-pin channel jumper blocks for damage, front power/fault LED for dead segments. Verify unbroken factory anti-static seal for surplus inventory.
- Live Testing: Seat the PCB in a populated HR test rack loaded with SPBRC410 CPU and multi-signal sensor simulators (TC, RTD, 4–20mA, ±10V). Run 24-hour continuous full 16-channel cyclic sampling. Simulate open-circuit sensor faults to validate diagnostic flag output. Track 5 V backplane stability with a Fluke 115 precision multimeter for the full test window.
- Electrical Testing: Execute 1500 VAC megger insulation test between all field input circuits and chassis PE ground; pass threshold set at >10 MΩ. Validate reverse backplane polarity protection triggers without damaging 24-bit A/D converters.
- Firmware/Config Backup: Record factory calibrated CJC offset and channel gain values. Document six-pin jumper block signal configuration templates for NTAI06 termination wiring reference.
- Final QC & Packaging: Wipe gold backplane connector pins to remove storage oxidation. Encase the PCB in anti-static foam inside shock-resistant export cartons. Apply physical QC Passed labels listing serial number and completed test metrics. Bench oscilloscope calibration logs available for pre-shipment review upon request.
Installation Pitfalls & Guide (Engineer to Engineer)
❗Firmware Mismatch Risk: This hardware uses legacy Infi90 ModuleBus firmware; pairing it with newer SPASI23-focused controller firmware creates unreadable analog channel values.Risk Outcome: Zero valid temperature/pressure readings visible on DCS HMI screens.Prevention Step: Confirm SPBRC410 CPU firmware revision supports IMASI-series legacy I/O before rack power-up; archive old firmware backup for retrofit racks.
❗DIP/Jumper Error Risk: The unit uses six-pin channel jumper blocks, unlike four-pin blocks on IMASI13. Reusing old IMASI13 jumper settings produces invalid signal scaling.Risk Outcome: Severe measurement offset, false high/low process alarms.Prevention Step: Photograph jumper block layouts on the original card before removal; follow NTAI06 wiring schematics for six-pin configuration mapping.
❗Wiring Incompatibility Risk: Non-matching NTAI06 termination units lack the required CJC routing traces for thermocouple sensors.Risk Outcome: Uncompensated TC readings with 10°C+ permanent offset.Prevention Step: Deploy only OEM NTAI06 terminal assemblies paired with the device; third-party generic termination blocks are not validated.
❗Power Draw Miscalculation Risk: Six of these high-current analog cards exceed single CMA198 supply’s 4 A continuous output rating.Risk Outcome: Persistent backplane voltage sag, reduced A/D resolution, intermittent sensor open-circuit false alarms.Prevention Step: Maintain minimum 20% power overhead per supply; split dense I/O loads across multiple parallel rack power PCBs.
❗ESD Dangers: Static discharge from dry boiler control room air damages precision 24-bit A/D converter circuits on the PCB. A single ungrounded handling incident renders all 16 channels uncalibrated.Risk Outcome: Permanent channel offset drift with no visible exterior hardware damage.Prevention Step: Touch bare cabinet ground metal for three full seconds before handling backplane edge connectors and jumper blocks.
4-Step Replacement Guide
- Pre-install: Confirm rack holds at least two parallel CMA198 power supplies to avoid full rack analog signal loss during swap. Capture photos of all six-pin channel jumper positions on the old card.
- Removal: Unlatch the HR card slot release tab, pull straight outward without twisting the PCB to avoid bending gold edge contact pins.
- Install: Align the new unit’s edge connector with the rack backplane, push fully seated until the latch clicks locked; replicate all jumper configurations from the photographed reference.
- Power-on Test: Monitor front power LED steady green; cycle all analog channel simulation signals to confirm consistent, drift-free measurements and functional open-sensor fault diagnostics.
FAQ
Q: I maintain an aging Harmony boiler control rack with failing IMASI13 analog input cards paired with SPBRC410 controllers. Can the device serve as a direct drop-in replacement without termination rewiring?A: Mechanical rack form factor and backplane pinout match fully for drop-in installation, but six-pin jumper blocks differ from IMASI13 four-pin layouts. No field cable rewiring on the terminal base is required, only jumper reconfiguration per OEM schematic.Q: What lead times apply for stocked hardware versus pre-calibrated custom variants?A: Standard in-stock PCB assemblies ship within 3–5 business days via global air freight. Custom factory pre-calibrated CJC offset variants carry a 12–16 week OEM lead time and are not stocked as surplus inventory.Q: Does the 12-month warranty cover damage from misconfigured channel jumpers or ungrounded ESD handling?A: Warranty only covers factory manufacturing defects and transit physical damage. Incorrect jumper signal configuration, ungrounded static handling, and installation on incompatible non-HR rack backplanes fall outside covered failure modes. Paid remote analog channel configuration support is available post-install.Q: Can this legacy analog card be swapped for SPASI23 during a rack upgrade project without reworking all termination wiring?A: No. SPASI23 uses revised backplane communication timing and different channel conditioning circuitry; the two models require separate termination base wiring rework and full S+ Composer control logic reconfiguration. This unit remains the direct like-for-like spare for original IMASI-series hardware.Q: Is this analog input PCB rated for Class 1 Div 2 hazardous cabinet installation inside refinery MCC rooms?A: No. The open HR slot PCB design lacks intrinsic safety ratings for classified explosive atmosphere locations. ABB manufactures separate IS-certified analog I/O hardware lines for hazardous area cabinet deployments.Q: Can thermocouple, RTD, and 4–20mA pressure sensors run on separate channels of one card without cross-talk interference?A: Yes. Hardware assigns fully isolated signal conditioning and independent 24-bit A/D converters to every channel with 1500 V galvanic separation between signal groups; no external signal isolator hardware is required for mixed-sensor cabinet layouts.Q: What QA documentation ships with each unit for plant maintenance record retention?A: Every PCB includes a physical QC Passed label stamped with serial number and completed test checklist metrics. Digital copies of 24-hour full-channel cyclic load logs, 1500 V insulation megger reports, and cold junction calibration validation data can be emailed prior to shipment upon buyer request.
