Schneider Electric Modicon MA Series Modules: MA-0185-100 LINE TAP / COAX CBL SYS —

Technical Dossier

Product Details And Specifications

Schneider Electric Modicon MA Series Technical Notes

The Schneider Electric Modicon MA Series represents a foundational layer of coaxial cable tap and line interface hardware deployed across global heavy industry. Installations span petrochemical refineries, nuclear power generation facilities, offshore oil platforms, and large-scale chemical processing plants where Modicon Quantum and Modicon 984 PLCs form the backbone of distributed control. The MA Series coaxial bus tap components — including the MA-0185-100 LINE TAP / COAX CBL SYS — provide the physical-layer connectivity between Modicon remote I/O drops and the coaxial trunk cable. Their role is infrastructure-critical: a failed tap or cable system segment can isolate an entire remote I/O rack from the host processor. Because these components are embedded in long-lifecycle plant designs, demand for exact-replacement parts persists well beyond the series' active production window.

The Evolution of Modicon MA Series Architecture

The Modicon MA Series coaxial tap hardware was developed in parallel with the Modicon 984 and early Quantum remote I/O architecture, which used RG-6 or RG-11 coaxial cable as the physical medium for the Modicon Remote I/O (RIO) network. This network operates at 57.6 kbps or 115.2 kbps and uses a proprietary token-passing protocol. The MA Series taps provide the T-connection between the trunk coaxial cable and the drop cable leading to each remote I/O adapter (BM•CRA or equivalent).

Early MA Series components were designed for the Modicon 984 controller family (A120, A984, PC-E984). As Schneider Electric transitioned the platform to the Modicon Quantum (140-series) in the 1990s, the coaxial RIO infrastructure remained backward-compatible, and MA Series taps continued to be specified in new Quantum installations through the 2000s. The Modicon M340 and later Ethernet-based I/O architectures (Modbus TCP, EtherNet/IP) represent the modern replacement path, but the installed base of coaxial RIO systems remains extensive. Plants operating on 20–40 year maintenance cycles continue to require MA Series hardware for like-for-like replacement without system-wide migration.

Compatibility note: MA Series taps are passive RF components. They are compatible across all Modicon coaxial RIO generations provided the impedance (75 Ω) and connector type (F-type or BNC, depending on variant) match the installed trunk cable specification.

Modicon MA Series Full Catalog & Functionalities (SKU List)

Coaxial Line Tap & Cable System Components

• MA-0185-100: LINE TAP / COAX CBL SYS — Standard coaxial line tap assembly for Modicon RIO trunk cable, 75 Ω, single-drop configuration.
• MA-0185-001: Coaxial line tap, single port, for RG-6 trunk cable, F-connector termination.
• MA-0185-002: Coaxial line tap, dual port, for branched drop configurations on RIO segment.
• MA-0186-100: Coaxial cable tap system, extended drop length variant, for remote I/O drops up to 300 m.
• MA-0187-100: Trunk cable terminator, 75 Ω, end-of-segment resistive termination for coaxial RIO bus.
• MA-0188-100: Coaxial cable splice kit, field-installable, for trunk cable repair or extension.

Remote I/O Drop Cable Assemblies

• MA-0190-100: Drop cable assembly, 1 m, RG-6, F-connector to BNC, for RIO adapter connection.
• MA-0190-300: Drop cable assembly, 3 m, RG-6, F-connector to BNC.
• MA-0190-500: Drop cable assembly, 5 m, RG-6, F-connector to BNC.
• MA-0191-100: Drop cable assembly, 1 m, RG-11, heavy-duty, for high-noise industrial environments.
• MA-0192-100: Coaxial patch cable, 1 m, BNC-to-BNC, for test and diagnostic use on RIO segments.

Bus Repeaters & Signal Conditioning

• MA-0200-100: Coaxial RIO bus repeater, extends segment length beyond standard 1500 m limit.
• MA-0201-100: Bidirectional coaxial repeater, for multi-segment RIO networks with more than 31 drops.
• MA-0202-100: Signal conditioner / line driver, compensates for cable attenuation on long trunk runs.

Mounting & Accessory Hardware

• MA-0210-100: DIN rail mounting bracket kit for MA Series tap assemblies, 35 mm rail compatible.
• MA-0211-100: Weatherproof enclosure kit for outdoor or wash-down MA Series tap installations.

Quality Control for the Modicon MA Series Range

Coaxial tap and cable system components present specific test challenges compared to active electronic modules. DriveKNMS applies the following verification procedures to all MA Series inventory:

• Impedance verification: Each tap is tested at 75 Ω ± 2% using a calibrated vector network analyzer (VNA). Deviation beyond tolerance indicates internal damage or counterfeit construction.
• Insertion loss measurement: Signal attenuation through the tap is measured across the 10 MHz–200 MHz band to confirm the component meets the Modicon RIO frequency response specification.
• Connector integrity inspection: F-type and BNC connectors are inspected for pin straightness, thread condition, and dielectric integrity. Corroded or deformed connectors are rejected.
• Cable assembly continuity and shield test: Drop cable assemblies are tested for center conductor continuity, shield continuity, and center-to-shield isolation (minimum 100 MΩ at 500 VDC).
• Physical inspection: Housings, strain reliefs, and mounting hardware are inspected for cracks, UV degradation, and mechanical deformation consistent with improper storage or installation.

Units that pass all five stages are tagged with a DriveKNMS QC reference number and are eligible for shipment. Units with any out-of-tolerance result are quarantined and not offered for sale.