2. Model Definition

51304443: Base model for 16-channel compact TC/RTD LLAI FTA, dedicated pairing with MC-AIL72 low-level temperature IOP module

-200: Medium heavy reinforced industrial PCB grade

Medium heavy-duty full-board conformal coating, excellent resistance to sustained high humidity, heavy dust and mild acidic/alkaline corrosive vapors

High-capacity bidirectional transient, ESD and wiring fault surge suppression diodes with elevated energy absorption

Multi-stage cascaded ultra-low-noise differential EMI filter network for heavily electrically noisy industrial environments

Precision reinforced balanced ultra-low-noise differential trace layout optimized for weak millivolt thermocouple signals

High-precision per-channel integrated Cold Junction Compensation (CJC) sensing elements

Matched IOP Hardware: MC-AIL72 (Compact UCN bus 16-point high-density TC/RTD analog input IOP card)

Incompatible Hardware: HLAI high-level analog input FTA, HLAO analog output FTA, discrete DI/transistor/relay DO FTA, pulse counter FTA, serial communication FTAs

3. Technical Specifications

Channel Count: 16 independent low-level temperature input channels

Supported Field Sensors

Thermocouple (TC): J, K, T, E, R, S, B, N type mV signals

RTD: Pt100, Pt1000 (2-wire & 3-wire resistance temperature detectors)

FTA Structure: Passive termination block; built-in per-channel high-precision CJC for TC cold junction correction; RTD excitation current fully supplied by MC-AIL72 IOP

PCB Protection: Medium heavy-duty full conformal coating; flammability rating UL94 V0

Terminal Type: Compression screw terminals, compatible with solid/stranded copper wire up to 14 AWG

Form Factor: Standard Size B footprint, snap-on quick DIN rail installation for 35 mm standard rails

Operating Ambient: 0℃ ~ +60℃ (indoor cabinet only); broader tolerance for high humidity, dust and mild corrosion than -100/-150 grades

Circuit Architecture

Ultra-low-noise symmetric balanced differential signal routing to minimize attenuation of tiny TC millivolt outputs

Multi-stage per-channel low-pass EMI filtering to eliminate severe plant switching noise from VFDs, contactors and switchgear

High-energy bidirectional transient overvoltage surge suppression

High-precision integrated CJC temperature sensors for accurate thermocouple offset correction

Matched impedance layout with thick reinforced physical channel partition barriers to eliminate inter-channel signal crosstalk

Redundancy Compatibility: Fully supports primary/standby redundant MC-AIL72 IOP architecture; hot-swap IOP card replacement permitted

Approximate Unit Weight: 0.360 kg

4. Interface & Communication Configuration

Inner IOP Connection: Locking flat ribbon cable connector directly mates to MC-AIL72 pin headers. Integrated reinforced cable strain relief prevents pin header deformation or fracture caused by long-term pulling tension on delicate TC/RTD extension wiring harnesses. No independent communication chip; calibrated temperature process variable values transmit over UCN control bus to DCS controller via MC-AIL72.

Field Outer Terminals: Distinct silkscreened terminal zones separated for TC ± wiring and 2/3-wire RTD connections, with clear CJC reference marking. Thick physical channel separation drastically reduces inter-channel low-level signal interference.

Reference Power Supply: Cabinet 24VDC system power provides RTD excitation current through the MC-AIL72 IOP interface.

5. Core Functions

Cable Strain Relief: Reinforced strain relief protects fragile MC-AIL72 IOP pin headers from mechanical stress, bending and fatigue breakage under continuous field wiring tension.

Multi-Stage Advanced Low-Noise Signal Preservation: Reinforced symmetric differential trace routing fully preserves weak thermocouple millivolt signals, delivering stable high-precision temperature readings even in heavy EMI environments.

Multi-Tier EMI Noise Rejection: Cascaded high-performance filters suppress extreme interference from large VFD banks, high-current contactors and medium-voltage switchgear, nearly eliminating temperature PV drift and fluctuation to secure control loop stability.

Reinforced Surge & Transient Protection: High-capacity clamping diodes absorb intense induced voltage spikes, wiring fault transients and minor lightning induction surges, robustly safeguarding the ultra-sensitive low-level input front-end of MC-AIL72.

Medium Heavy-Duty Environmental Barrier: Thick conformal coating fully encapsulates PCB substrates, solder pads, copper traces and passive components. It enables stable 24/7 uninterrupted temperature monitoring operation in cabinets with long-term high humidity, heavy dust accumulation and trace mild acidic/alkaline corrosive fumes.

Isolated Single-Channel Maintenance: Separated terminal layout allows sensor replacement, full loop resistance verification, precision field calibration and fault troubleshooting for one channel without disrupting measurement performance of the remaining 15 temperature monitoring circuits.

Redundancy Hot-Swap Capability: Standby MC-AIL72 IOP cards can be replaced online without halting critical furnace, reactor, boiler and heat exchanger temperature safety interlock and closed-loop control logic.

6. Application Scenarios

Applicable Industries

Petrochemical complexes, chemical processing plants, thermal power stations, oil & gas refineries, pulp & paper mills, water treatment facilities, medium-to-high humidity pharmaceutical batch production lines.

Temperature Measurement Loops

Reactor vessel skin temperature, boiler/furnace tube temperature, distillation column tray temperature, extrusion/injection mold temperature, heat exchanger inlet/outlet temperature, sterilizer batch temperature tracking, furnace safety skin temperature monitoring.

Cabinet Deployment

Dedicated compact terminal base for 16-point low-level temperature analog input slots inside high-density space-saving DCS I/O control cabinets.

7. Operation, Wiring & Maintenance Instructions

Wiring Standards

Thermocouple circuits must use matching-type TC extension wire; strictly maintain polarity to avoid large thermal offset measurement errors.

For 3-wire RTD installation, use equal-length, identical-gauge lead wires to balance line resistance for precise resistance measurement.

Deploy shielded twisted-pair cable for long-distance field runs; apply single-point shield grounding exclusively at the cabinet FTA side to prevent ground loop interference.

Route low-level temperature cables physically separate from high-current AC power cables to minimize electromagnetic coupling noise.

Spare Part Interchangeability

51304443-200 shares identical core low-noise temperature circuit topology with -100/-150 variants for direct emergency field substitution. The -200 medium heavy-duty grade is selected for cabinets with obvious high humidity, heavy dust or trace corrosive gas environments requiring elevated long-term reliability.

Standard Fault Troubleshooting Flow

Abnormal/unstable temperature PV → Retighten compression terminal screws → Verify TC/RTD sensor continuity and physical integrity → Inspect extension wire polarity & total loop resistance → Confirm ribbon cable fully seated and locked into IOP header → Diagnose operational health of paired MC-AIL72 IOP card.