Metso D201925

Technical Specifications

• Model Series: ACN CS D2019 Field Bus Interface Subseries
• Power Input: 24 VDC ±10%, rated power consumption 12.5 W
• Field Bus Communication Interfaces: 2 × isolated RS485 field bus channels
• Supported Field Bus Protocols: Metso Neles Fieldbus, Modbus RTU, HART pass-through
• Backplane Bus: Metso proprietary ACN high-speed internal bus
• Onboard Memory: 256 KB RAM, 512 KB Flash protocol storage
• Single Bus Node Capacity: Max 32 field devices per RS485 channel
• Bus Baud Rate Range: 1200 bps – 115200 bps auto-adaptive
• Operating Temperature Range: -20 °C to +60 °C
• Storage Temperature Range: -40 °C to +85 °C
• Relative Humidity Tolerance: 5%–95% non-condensing
• Protection Grade: IP20 module body; IP54 when fully installed in standard Metso control rack
• Dimension: 220 mm (H) × 160 mm (W) × 35 mm (D)
• Net Weight: 0.77 kg

Functional Features

1. Dual independent isolated RS485 field bus channels supporting parallel device networking
2. Native compatibility with all Metso Neles intelligent valve positioners and process transmitters
3. Built-in HART signal pass-through circuit for configuration of HART-compatible field instruments
4. Real-time bus node fault scanning with individual channel LED fault indication on front panel
5. Onboard Flash memory permanently stores bus protocol mapping and device tag configurations
6. Full hot-swap compatible with all slots of Metso ACN CS rack backplane
7. Hardware bus short-circuit protection that automatically isolates faulty bus branches without rack-wide communication failure
8. Bidirectional data forwarding between field bus nodes and rack master processor D201832 / D201832L

Performance Parameters

• Bus Communication Latency: ≤ 1.5 ms per device data polling cycle
• Channel Isolation Voltage: 1500 VAC between field bus circuit and ACN backplane bus
• Surge Withstand Capacity: 2 kV ESD contact discharge, 4 kV electrical fast transient
• Vibration Resistance: 10–150 Hz, 1 g continuous operation without bus signal distortion
• Maximum Field Bus Cable Length: 150 m shielded twisted pair per RS485 channel
• Data Transmission Error Rate: ≤ 10⁻¹² under standard industrial cabinet grounding conditions

Material Composition

• Main Circuit Substrate: FR4 high-Tg industrial multi-layer fiberglass PCB with low signal crosstalk design
• Field Bus Terminal Connectors: Gold-plated phosphor bronze screw terminal blocks with anti-loosening spring washers
• Isolation Components: High-speed optocoupler isolation chips for each RS485 channel
• Signal Shielding Layer: Single-layer 0.8 mm cold-rolled steel partial signal isolation shield
• Mounting Frame: Black extruded aluminum alloy with hard anodized anti-corrosion coating
• Core Processing Chip: Wide-temperature industrial 32-bit communication microcontroller

Structural Characteristics

• Standard 1U rack plug-in card structure with dual side locking latches for fixed rack installation
• Front panel segmented layout: power LED, channel 1 bus status LED, channel 2 bus status LED, general fault LED
• Rear edge gold finger connector for direct electrical docking with ACN backplane bus slot
• Physically separated wiring terminal compartments for Channel 1 and Channel 2 field bus cables to avoid cross-channel interference
• Independent internal isolation barriers between field bus analog/digital circuits and rack backplane digital circuits
• Built-in micro ventilation slits on front panel for passive heat dissipation without auxiliary fans

Working Principle

Advantage Highlights

1. Dual independent bus channel design realizes segmented field device networking to reduce single-point bus failure impact
2. Native Neles Fieldbus compatibility eliminates third-party protocol conversion hardware for Metso valve equipment
3. Integrated HART pass-through function removes need for separate HART modem devices in control cabinets
4. Channel-level short-circuit isolation prevents total field bus communication collapse during field wiring faults
5. Hot-swap maintenance capability allows module replacement without powering down the entire control rack or disconnecting field instruments
6. Pre-programmed protocol mapping templates for all standard Metso process instruments reduce on-site commissioning time
7. Compact single-slot form factor minimizes rack slot occupation compared to external multi-channel bus gateways

Applicable Industries

• Mining & mineral processing: intelligent flotation valve, thickener actuator and crusher condition monitoring instrument networking
• Pulp & paper manufacturing: digester, bleaching line and stock flow intelligent valve positioner bus connection
• Chemical & petrochemical processing: reactor pressure/temperature transmitters and control valve field bus networking
• Municipal industrial wastewater treatment: dosing valve, flow meter and water quality sensor centralized bus communication
• Cement production: rotary kiln temperature transmitters and exhaust gas control actuator bus integration

Installation Requirements

1. Install exclusively within Metso standard ACN CS series 8-slot or 16-slot control rack empty slave slots
2. Maintain a minimum 10 mm vertical ventilation gap between D201925 and adjacent rack modules for heat dissipation
3. All field bus wiring must use double-shielded twisted pair communication cables; cable shielding shall be single-point grounded at cabinet PE terminal only
4. Cabinet main PE grounding resistance shall not exceed 4 Ω to fully activate EMC anti-interference performance
5. Verify stable 24 VDC backplane bus power supply before executing hot-swap replacement of the module
6. Separate field bus signal cable routing from high-power motor, inverter and power cable wiring channels inside control cabinets
7. Limit each RS485 channel to maximum 32 connected field devices to avoid bus polling delay overload

Operation & Maintenance Precautions

1. ESD anti-static wrist strap and conductive anti-static mat are mandatory during module disassembly, wiring modification and parameter configuration
2. Strictly prevent liquid splashing, conductive dust and metal debris accumulation on PCB circuit surfaces
3. Conduct semi-annual inspection of all field bus terminal block screw tightness to eliminate loose contact induced communication faults
4. Do not install D201925 adjacent to high-frequency variable frequency drive modules to avoid electromagnetic signal interference
5. Spare D201925 modules shall be stored in sealed anti-static packaging bags with silica gel desiccant packs to prevent humidity circuit corrosion
6. Cut off all field bus external cable power supply before disassembling field wiring terminal blocks
7. Complete full backup of field bus device tag and protocol mapping parameters before module replacement to avoid reconfiguration workload
8. Avoid mixing different protocol devices on the same RS485 channel to prevent bus polling conflict and data loss