ABB LOMI4 367

1. Product Overview

The ABB LOMI4 367 is a high-precision analog output module designed for ABB’s distributed control systems (DCS) and programmable logic controllers (PLC). Part of the robust LOMI series, this module converts digital control commands into smooth, continuous analog signals for modulating final control elements such as variable frequency drives, valve positioners, and chart recorders. With its 4-channel design and exceptional signal integrity, the LOMI4 367 is trusted in continuous process industries where accuracy and noise immunity are critical.

2. Structure & Composition

The LOMI4 367 is housed in a shielded, powder-coated metal casing that provides superior electromagnetic interference (EMI) protection. Key internal components include:

• Dual 16-bit DACs (digital-to-analog converters) – two channels per DAC for synchronized output
• Per-channel output buffer – low-impedance drivers capable of driving up to 750Ω loads
• Galvanic isolation barrier – 1500Vrms isolation between field side and logic side
• Self-recovering fuses – one per channel, resettable after overcurrent events
• Front panel – 20-pin hinged terminal block with transparent cover and individual channel status LEDs

The module mounts directly onto an ABB S800 I/O backplane and communicates via the ModuleBus protocol.

3. Technical Parameters 

4. Key Features

• HART protocol pass-through on all four channels for smart device communication
• Open-circuit detection on voltage outputs and short-circuit protection on current outputs
• Output ramping configurable via software to prevent process shock
• Redundant power input with automatic failover
• Diagnostic LEDs – green (normal), yellow (warning), red (fault) per channel
• Cold junction compensation for thermocouple simulation applications
• Conformal coating on PCB for moisture and dust resistance

5. Installation & Maintenance

Installation:

• Insert the LOMI4 367 into any free slot of an ABB S800 I/O station (e.g., CI801, CI853).
• Secure the module with the two captive screws (torque 0.4 Nm).
• Connect field wiring to the removable terminal block using 0.5–1.5 mm² (20–16 AWG) wire.
• Assign I/O addresses using ABB Control Builder or 800xA configuration tool.

Maintenance:

• No periodic calibration required under normal conditions (recommended interval: 3 years for critical loops).
• Clean the front label and terminal block with isopropyl alcohol and a lint-free cloth.
• If a channel LED shows red, perform a loop test: disconnect the field device and measure output with a multimeter.
• Replace the module only after removing loop power and backplane power.

6. Application Fields

• Continuous chemical reactor temperature control (to a I/P converter)
• Paper machine headbox pressure regulation via servo valve
• Pharmaceutical bioreactor pH adjustment (acid/base dosing pumps)
• Power plant boiler feedwater control valve positioning
• Water treatment plant chemical metering pumps
• HVAC chilled water valve control in large commercial buildings

7. Additional Information

• Certifications: ATEX Category 3 (Zone 2), IECEx, CSA Class I Div 2, RoHS
• MTBF: >600,000 hours (per Siemens SN 29500)
• Ambient temperature: –40°C to +70°C (operating); –40°C to +85°C (storage)
• Humidity: 5–95% non-condensing
• EMC compliance: EN 61326-1 (Industrial immunity)
• Software compatibility: ABB 800xA, Symphony Plus, Compact Control Builder AC 800M
• Warranty: 18 months from shipment

The ABB LOMI4 367 delivers laboratory-grade analog output accuracy in a rugged, industrial package, making it the ideal choice for mission-critical loop control in refineries, power stations, and water facilities.