Overview
The IMFEC12 is a dedicated analog input module for ABB’s INFI 90® OPEN Strategic Process
Management System, designed to acquire analog process data from conventional transmitters (e.g.,
pressure, temperature, level transmitters) and standard analog devices, then transmit this data to INFI
90 control modules (Multi-Function Processor/IMMFP01/02/03, Multi-Function
Controller/IMMFC03/04/05). As a counterpart to the IMFEC11 (which adds smart transmitter support),
the IMFEC12 focuses on reliable, high-precision analog signal acquisition for industrial control
applications, with no support for FSK digital communication or smart devices.
Physically, the IMFEC12 occupies one slot in a standard INFI 90 Module Mounting Unit (MMU) and
features a single printed circuit board (PCB) with integrated analog-to-digital (A/D) conversion, signal
conditioning, and communication circuitry. It provides 15 independent analog input channels
(configurable for current or voltage signals) and uses three card-edge connectors for power (P1: ±15
VDC, +5 VDC), I/O Expander Bus communication (P2), and analog input signals (P3, via termination
devices). The front panel includes two status LEDs (red/green) for operational feedback—simplifying
on-site monitoring and troubleshooting.
Key design features include high noise immunity (90 dB common mode rejection at 50/60 Hz), wide
input compatibility (4–20 mA, 1–5 VDC, 0–1 VDC, 0–5 VDC, 0–10 VDC, -10 to +10 VDC), and
compliance with industrial safety standards (CSA C22.2 No. 1010.1-92 for non-hazardous locations,
FM Class I Division 2 Groups A–D). It operates in harsh environments (0–55°C ambient temperature, 5–
95% non-condensing humidity) and is a direct replacement for the legacy IMASI02 analog input
module (without supporting baseband communications). The module relies on termination devices
(NTAI05 Termination Unit, NIAI04 Termination Module) for field wiring and uses Function Code (FC)
132 in the control module configuration for signal access and channel setup.
Core Functionality
2.1 15-Channel Analog Signal Acquisition
The IMFEC12’s primary role is to accurately capture analog process signals from conventional transmitters and convert them to digital data for INFI 90 control modules, with key capabilities tailored to industrial measurement needs:
Multi-Signal Compatibility: Supports a wide range of standard analog inputs to match common industrial transmitter outputs:
Current signals: 4–20 mA (system-powered or externally powered).
Voltage signals: 1–5 VDC, 0–1 VDC, 0–5 VDC, 0–10 VDC, -10 to +10 VDC (single-ended or differential).
Input configuration is managed via termination devices (NTAI05/NIAI04), with dipshunts selecting signal type for each channel (no on-module jumpers required for the IMFEC12).
High-Precision A/D Conversion: Uses a 12-bit dual-slope A/D converter with integrated signal conditioning, achieving ±0.1% full-scale range (FSR) accuracy at 25°C (77°F). The converter samples each channel 5 times per second to ensure real-time data capture, with built-in overvoltage protection (±30 VDC) to shield circuitry from field transients.
Noise Rejection: Two-pole low-pass filters per channel reduce input noise, while differential signal processing provides 90 dB common mode rejection (CMR) at 50/60 Hz—critical for minimizing interference from industrial power lines and nearby electrical equipment. Common mode voltage range is -12 VDC to +15 VDC, ensuring stable operation in grounded or floating field configurations.
2.2 Control Module Communication & Data Handling
The IMFEC12 operates as a slave device on the INFI 90 I/O Expander Bus (12-line synchronous parallel bus), enabling bidirectional data exchange with control modules:
Address & Function Code Integration: A unique 6-bit address (0–63, set via 8-position dipswitch S1; Positions 3–8 for address, Positions 1–2 = closed) links the module to the control module. Control modules access the IMFEC12 via Function Code (FC) 132 (specification S1 = module address), configuring input type (current/voltage), range, and scaling for each channel.
Data Transmission:
Analog Input Data: After A/D conversion, digital values (12-bit resolution) are stored in on-board RAM. The control module reads this data via the I/O Expander Bus, with a first-in-first-out (FIFO) buffer ensuring smooth data transfer even during high-speed control cycles.
Status Feedback: The module transmits a 3-byte status report to the control module, including channel quality flags (good/bad), module identification (4 MSBs), and calibration status. A “bad quality” flag is set if a channel is out of range, the A/D converter fails, or the input signal is interrupted—enabling the control module to trigger alarms or fail-safe actions.
Auto-Calibration: The A/D converter uses internal reference voltages (±10 VDC) for periodic self-calibration, correcting for drift caused by temperature variations (±0.002% FSR/°C). This eliminates the need for manual potentiometer adjustments, reducing maintenance requirements.
2.3 Front-Panel Status Monitoring & Fault Detection
The IMFEC12 includes intuitive indicators and built-in diagnostics to ensure operational reliability and simplify troubleshooting:
Module Status LEDs:
Green ON, Red OFF: Normal operation (enabled, communicating with the control module, all channels checked good).
Red ON, Green OFF: I/O Expander Bus failure (no communication with the control module; check address, dipshunts, or bus connection).
Both OFF: No power (check P1 connections) or module not seated properly in the MMU.
Green Blinking (6 times/minute): Hardware failure (e.g., A/D converter error, RAM fault); replace the module.
Channel-Level Diagnostics: The module continuously checks each input channel for signal integrity. If a channel is out of the configured range (e.g., <4 mA or >20 mA for current inputs), the module marks it as “bad quality” and updates the status report. The control module can access this status via operator interfaces (OIS, EWS) to identify faulty transmitters or wiring.
Control Module Error Reporting: If the IMFEC12’s address (S1) does not match FC 132 specification S1, or if the I/O Expander Bus dipshunt is missing, the control module generates a “MISSING I/O MODULE” error. This error is logged in the control module’s status bytes (byte 3 = 03, bytes 4–5 = block number), guiding technicians to resolve addressing or bus issues.
2.4 Termination & System Integration
The IMFEC12 integrates seamlessly with INFI 90 termination devices and standardized cabling for flexible deployment:
Termination Device Compatibility:
NTAI05 Analog Input Termination Unit (panel-mounted, uses NKTU01 cables): Configures each channel for current/voltage via dipshunts, provides surge protection, and converts 4–20 mA current signals to voltage for the module.
NIAI04 Analog Input Termination Module (rack-mounted, uses NKTM01/NKTU02 cables): Similar to the NTAI05 but designed for dense rack installations, with dipswitches for input type selection and terminal blocks for field wiring.
No on-module jumpers are required for the IMFEC12—all input configuration is handled by the termination device, simplifying setup and reducing human error.
I/O Expander Bus Scalability: The bus can be extended to 6 MMUs via cables, supporting large-scale system configurations. A custom gate array in the module handles address detection, function code decoding, and data filtering—ensuring synchronous, noise-free communication with control modules.
2.5 Hot-Swappable & Low-Maintenance Design
Hot-Swapping: The module can be installed or removed from the MMU without powering down the INFI 90 system. Captive front-panel latches secure the module, and no pre-operational calibration is needed—minimizing downtime for maintenance or replacement.
Preventive Maintenance: Requires only periodic cleaning (static-safe vacuum for PCB/MMU dust removal) and tightening of power/ground connections (every 6 months or plant shutdown). Edge connectors can be cleaned with an 80/20 isopropyl alcohol/distilled water mixture to maintain signal integrity.
Legacy Compatibility: Directly replaces the IMASI02 analog input module, with identical mounting, power requirements, and FC 132 configuration—enabling easy upgrades of existing INFI 90 systems without reconfiguring control logic. It also works with all INFI 90 control modules (IMMFP, IMMFC) running compatible firmware (e.g., IMMFP01/02 E.1+, IMMFC03 L.1+).
ABB Bailey INFI 90 Series: System Structure & Key Components
The ABB Bailey INFI 90 series is a modular distributed process control system (DCS) tailored for
industrial automation and safety-critical scenarios, featuring a hierarchical architecture that connects
field equipment, slave modules, master controllers, and operator interfaces. At its core, the system
relies on master-slave communication to enable process monitoring and control: the Multi-Function
Processor (MFP: IMMFP01/02) and Network 90 Multi-Function Controllers serve as central master
units, while the IMASI02 (Analog Slave Input Module) acts as a dedicated slave component that
inputs 15 channels of analog signals from field devices (e.g., sensors, Bailey smart transmitters) to the
master controllers. Critical supporting components include termination devices (NTAI05 Termination
Unit, NIAI04 Termination Module) that configure and route field signals to the IMASI02 via specialized
cables (NKTU01, NKTM01), and the Slave Expander Bus (a backplane-mounted parallel bus in the
Module Mounting Unit/MMU) that enables real-time data exchange between the IMASI02 and MFP.
Operator interfaces like the Operator Interface Station (OIS), Configuration and Tuning Terminal (CTT),
and Smart Transmitter Terminal (STT) further integrate with the system—allowing users to configure
the MFP (via FC 132/133), send commands to smart transmitters through the IMASI02, and monitor
process status, while the Controlway and INFI-NET/Plant Loop provide redundant, plant-wide
communication for seamless scalability.
