Honeywell 2MLI-A21C – Discrete Digital Input Module | TDC-3000 DCS Platform
Engineering Background: The Honeywell TDC-3000 (Total Distributed Control) system has been the backbone of process automation in refining, petrochemical, and power generation facilities for decades. The 2MLI-A21C is a discrete digital input module designed specifically for the TDC-3000 I/O subsystem, enabling reliable acquisition of on/off field signals from switches, contactors, and relay outputs into the DCS control loop.
Product Positioning: This module is the preferred choice for maintenance engineers and procurement specialists seeking a verified, drop-in replacement or expansion card for existing TDC-3000 infrastructure. It eliminates costly system migrations by extending the operational life of proven DCS architectures.
Complete Technical Specifications
- Part Number / SKU: 2MLI-A21C
- Manufacturer: Honeywell Process Solutions
- Series / Platform: TDC-3000 / TotalPlant Solution (TPS)
- Module Type: Discrete (Digital) Input Module
- Input Channel Count: 16 channels (typical for MLI series)
- Input Signal Type: Discrete / Digital (dry contact or voltage)
- Communication Bus: Local Control Network (LCN) / Data Hiway
- Form Factor: Card-cage plug-in module
- Weight: Approx. 220 g
- Country of Origin: United States
- HS Code: 8537.10
Proven Application Environments
- Petroleum refining and upstream oil & gas facilities
- Petrochemical and specialty chemical plants
- Power generation (coal, gas, nuclear auxiliary systems)
- Pulp & paper and continuous process manufacturing
- Pharmaceutical batch and continuous production lines
- Any facility running Honeywell TDC-3000 or TPS DCS architecture
Engineering Advantages
- Direct Compatibility: Plug-and-play replacement within TDC-3000 card cages — no firmware reconfiguration required in most installations.
- Signal Integrity: Designed for industrial noise immunity, suitable for field environments with high EMI/RFI exposure.
- Extended Asset Life: Enables continued operation of TDC-3000 systems without full DCS migration, protecting capital investment.
- Proven Reliability: Honeywell MLI-series modules are field-proven across thousands of installations globally over 20+ years.
- Reduced Downtime: Stocked and ready to ship — critical for minimizing unplanned outage duration.
System Architecture & Signal Flow
The 2MLI-A21C resides in the TDC-3000 I/O card cage and interfaces directly with the Local Control Network (LCN) or Data Hiway backplane. Field discrete signals (e.g., valve open/closed, motor run/stop, alarm contacts) are wired to the module’s terminal block. The module conditions and digitizes these signals, transmitting status data to the associated Process Manager (PM) or Advanced Process Manager (APM) controller node for logic execution and historian archiving.
Sourcing & Quality Verification
- All units sourced from verified industrial surplus, OEM-authorized channels, or decommissioned plant inventories.
- Each module undergoes visual inspection, label verification, and functional bench testing prior to shipment.
- Traceability documentation available upon request for regulated industries.
- Packaging: ESD-safe anti-static bag + foam-lined carton for international transit protection.
Procurement Process
- Confirm Part Number: Verify 2MLI-A21C matches your TDC-3000 I/O slot requirement and firmware revision compatibility.
- Request Quote: Contact support@konmask.com with quantity, required lead time, and destination port.
- Order Confirmation: Purchase order accepted via email; proforma invoice issued within 24 hours.
- Shipment: DHL / FedEx / UPS international express; EXW Xiamen or CIF destination available.
- Documentation: Commercial invoice, packing list, and test report included; CO and FORM E available on request.
Technical FAQ
Q: Is the 2MLI-A21C compatible with both TDC-3000 and TPS systems?
A: Yes. The MLI-series modules are compatible across TDC-3000 and its successor TotalPlant Solution (TPS) platforms, provided the card cage and backplane revision are compatible.
Q: Can this module be used as a direct replacement without reconfiguration?
A: In most cases, yes — the module is a drop-in replacement. However, engineers should verify the specific I/O slot assignment and channel configuration in the system database before hot-swapping.
Q: Do you provide a warranty?
A: Yes. Konmask.com provides a 90-day functional warranty on all tested modules. Extended warranty options are available for volume orders.
Q: What is the typical lead time?
A: In-stock units ship within 1–3 business days. For out-of-stock items, sourcing lead time is typically 2–4 weeks.
Q: Can you provide a test report or inspection certificate?
A: Yes. A functional test report is available upon request. Third-party inspection (SGS, BV) can be arranged for large orders.
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