2. Model Definition

51304441: Base model for 16-channel compact HLAI FTA, dedicated pairing with MC-AIH70 high-level analog input IOP module

-175: Intermediate reinforced industrial PCB grade

Medium-thick reinforced full-board conformal coating, superior resistance to sustained high humidity, heavy dust and mild corrosive vapors vs -100/-125

High-capacity bidirectional transient surge suppression diodes with elevated energy absorption rating

Multi-stage cascaded low-pass EMI filter network for heavily electrically noisy plant environments

Precision balanced matched impedance trace layout for uniform sampling accuracy across all 16 channels

Matched IOP Hardware: MC-AIH70 (Compact UCN bus 16-point high-density 4–20mA / 0–10V analog input IOP card)

Incompatible Hardware: LLAI TC/RTD FTA, HLAO analog output FTA, discrete DI/transistor/relay DO FTA, pulse counter FTA, serial communication FTAs

3. Technical Specifications

Channel Count: 16 independent high-level analog input channels

Supported Input Signals

4–20mA DC current loops (2-wire & 4-wire field transmitters)

0–10V DC voltage analog signals

FTA Structure: Passive termination assembly; 2-wire transmitter loop excitation power supplied via MC-AIH70 IOP

PCB Protection: Medium-thick reinforced 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 DIN rail mounting for 35 mm standard rails

Operating Ambient: 0℃ ~ +60℃ (indoor cabinet only); extended tolerance for high humidity, dust and mild corrosion compared to -100/-125

Circuit Architecture

Multi-stage per-channel low-pass EMI filtering to eliminate severe industrial switching noise

High-energy bidirectional transient overvoltage surge suppression

Uniform balanced impedance routing to guarantee identical signal response, gain and sampling speed for every channel

Reinforced physical channel partition barriers to suppress inter-channel analog crosstalk

Redundancy Compatibility: Fully supports primary/standby redundant MC-AIH70 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-AIH70 pin headers. Integrated cable strain relief prevents pin header deformation or fracture caused by long-term pulling tension from field instrument wiring harnesses. No standalone communication processor; calibrated process variable values transmit over UCN control bus to DCS controller via MC-AIH70.

Field Outer Terminals: Clearly silkscreened positive/negative signal terminals, with dedicated loop power taps for 2-wire transmitters. Thick physical channel separation minimizes analog crosstalk between adjacent measurement loops.

Loop Power Supply: Cabinet 24VDC system power delivers excitation current for 2-wire 4–20mA transmitters through MC-AIH70 IOP interface.

5. Core Functions

Cable Strain Relief: Protects delicate MC-AIH70 IOP pin headers from mechanical stress and breakage induced by continuous wiring tension.

Multi-Stage Enhanced EMI Noise Rejection: Cascaded high-performance filters suppress heavy interference from large VFD banks, high-current contactors and medium-voltage switchgear, stabilizing PV fluctuation and significantly improving PID closed-loop stability compared to -100/-125 grades.

Reinforced Surge & Transient Protection: High-capacity clamping diodes absorb intense induced voltage spikes, wiring fault transients and minor lightning induction surges, robustly safeguarding the sensitive analog input front-end of MC-AIH70.

Improved Reinforced Environmental Barrier: Medium-thick conformal coating fully encapsulates PCB substrates, solder pads, copper traces and passive components. It enables reliable 24/7 continuous measurement operation in cabinets with long-term high humidity, heavy dust and trace mild acidic/alkaline corrosive fumes.

Uniform Channel Sampling Consistency: Precision balanced impedance layout ensures matching response speed, measurement accuracy and noise immunity across all 16 high-density input channels.

Isolated Single-Channel Maintenance: Separated terminal layout allows transmitter replacement, full loop resistance testing, mA/voltage calibration and fault troubleshooting for one channel without disrupting measurement performance of the remaining 15 process loops.

Redundancy Hot-Swap Capability: Standby MC-AIH70 IOP cards can be replaced online without interrupting critical flow, pressure, level, temperature control and safety interlock 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.

Analog Measurement Loops

Differential pressure flow transmitters, gauge/absolute pressure transmitters, radar/displacer level transmitters, signal-converted RTD/thermocouple assemblies, pH/ORP/conductivity analytical transmitters, valve position feedback 4–20mA signals.

Cabinet Deployment

Dedicated compact terminal slot for 16-point HLAI inside high-density space-saving DCS I/O control cabinets.

7. Operation, Wiring & Maintenance Instructions

Wiring Standards

Strictly follow positive/negative signal polarity marked on terminals; reversed polarity leads to no valid PV or failure of 2-wire transmitters to power up.

Verify total loop resistance per channel stays within MC-AIH70’s 4–20mA drive load range for 2-wire instruments.

Use shielded twisted-pair instrument cable for all field runs; implement single-point shield grounding only at cabinet FTA side to eliminate ground loop currents.

Route analog signal cables physically separated from high-current AC power cables to reduce electromagnetic noise coupling.

Spare Part Interchangeability

51304441-175 shares identical core analog input circuit topology with -100/-125/-200 variants for direct emergency field substitution. The -175 grade is selected for cabinets with obvious elevated humidity, heavy dust or trace corrosive gas where basic -100/-125 lack reliability margin, while more cost-effective than full heavy-duty -200.

Standard Fault Troubleshooting Flow

No PV / fluctuating inaccurate analog readings → Retighten compression terminal screws → Measure mA/V output at transmitter terminals → Check 24V loop power integrity → Test loop open/short resistance → Confirm ribbon cable fully seated and locked into IOP header → Diagnose operational health of paired MC-AIH70 IOP card.