2. Model Definition

51304685: Base model for 16-channel non-isolated HART analog input FTA

-200: Medium heavy-duty reinforced PCB protection grade

Medium-thick reinforced full-board conformal coating with enhanced resistance to high humidity, heavy dust and mild-moderate corrosive gas

High-capacity bidirectional TVS surge suppression for transients, ESD and line faults, higher impact energy tolerance than -100/-150

Three-stage cascaded RC differential EMI filter optimized for high-noise plant areas with dense MCC and large VFD clusters

Global common ground bus for all 16 channels, no independent galvanic isolation barriers

Precision tight-tolerance loop current limiting resistors for uniform short-circuit overload protection of transmitters and IOP inputs

Extra-thick reinforced plastic channel baffles to eliminate inter-channel analog/HART signal leakage and measurement crosstalk

3. Technical Specifications

Channel Count: 16 common-ground channels, no per-channel galvanic isolation

Compatible Field Devices

Two-wire HART smart transmitters: pressure, differential pressure, mass/vortex/turbine flow, radar/float level, RTD/TC temperature, pH, ORP, dissolved oxygen, conductivity analytical transmitters

Backward compatible with conventional non-HART 4–20mA two-wire transmitters

FTA Structure: Passive non-isolated termination board without built-in power supply; integrated per-channel HART coupling, three-stage differential filtering, high-energy surge protection and short-circuit current limiting

PCB Protection: Medium-thick reinforced conformal coating; flammability UL94 V0

Terminal Type: Compression screw terminals compatible with solid/stranded copper wire up to 14 AWG; each channel has Ch+ / Loop– terminal pair sharing a unified ground bus

Form Factor: Standard B-size footprint, snap-on DIN rail mounting for standard 35 mm rails

Operating Ambient: 0℃ ~ +60℃ indoor cabinet; superior humidity, dust and mild corrosion tolerance versus -100/-150; not designed for continuous salt fog environments (select -325/-375 for coastal/offshore salt fog scenarios)

Circuit Architecture Parameters

Three-stage low-pass differential filtering to suppress severe EMI interference from large VFD systems, motor control centers and medium-voltage switchgear while fully preserving HART carrier amplitude

High-energy bidirectional TVS suppresses positive/negative transient high voltage on each shared-ground input loop

Common ground layout; ground potential offset between field and DCS leads to measurement drift and unstable HART communication

Calibrated tight-tolerance current-limit resistors prevent transmitter burnout and IOP high-impedance input damage during field short faults

Extra-thick baffles fully block inter-channel analog bleed and HART signal crosstalk

Redundancy Support: Fully compatible with primary/standby redundant non-isolated HART AI IOP; hot-swap FTA replacement without process shutdown is permitted

Approximate Unit Weight: 0.360 kg

4. Interface & Communication Configuration

Inner IOP Connection: Locking heavy-duty flat ribbon cable directly mates to non-isolated HART AI IOP pin headers. Reinforced cable strain relief prevents pin header deformation or fracture under sustained tension of long multi-core field instrument wiring harnesses.

Field Outer Terminals: Independent Ch+ / Loop– terminals for each two-wire transmitter loop; all loops share one unified ground bus aligned with DCS control ground potential.

Signal Mechanism: 4–20mA DC analog measurement signals overlaid with FSK HART digital signals via frequency division; passive low-distortion HART coupling integrated per channel.

HART Access: No dedicated auxiliary communication port; handheld HART communicator clamps directly across Ch+ and Loop– field terminals for commissioning, calibration and diagnostic data reading.

5. Core Functions

Common-ground HART mixed-signal transmission: Cost-effective single-ground architecture supporting mixed installation of HART smart and conventional 4–20mA transmitters.

Three-stage heavy EMI noise rejection: Suppresses intense electromagnetic interference from VFD banks, MCCs and medium-voltage switchgear to eliminate measurement jitter, fluctuation and frequent HART poll retries.

High-energy surge & short-circuit fault protection: Withstands lightning-induced line transients, equipment startup surges and field short-circuit high voltage to protect costly sensitive IOP high-impedance input circuits and field transmitters.

Uniform loop overload protection: Precision matched current limiting equally safeguards all connected transmitters against burnout from accidental wiring shorts.

Consistent channel linearity and HART matching: Ultra-precision passive components deliver identical measurement response and stable HART handshake across all 16 channels to reduce bulk calibration workload.

Redundant hot-swappable maintenance: Seamlessly follows primary/standby IOP switching logic; single-channel disconnection and troubleshooting do not affect operation of the remaining 15 measurement loops.

6. Application Scenarios

Applicable Industries

Petrochemical complexes, medium-heavy chemical plants, combined heat & power stations, large oil & gas refineries, pulp & paper mills, high-humidity wastewater treatment, medium-to-high humidity pharmaceutical batch production lines

Typical Measurement Loops

Emergency safety pressure/differential pressure HART monitoring transmitters

High-flow process HART flow transmitters

Large storage tank HART level transmitters

Furnace/reactor RTD/TC high-temperature HART transmitters

Mildly corrosive media pH/DO/conductivity HART analytical transmitters

Suitable for single-ground plant layouts, VFD-dense process areas, cabinets with long-term high humidity and heavy dust accumulation, and atmospheres containing mild-moderate acidic/alkaline volatile vapors. Not applicable for offshore platforms or coastal sites with continuous salt fog exposure; upgrade to -325/-375 ultra-heavy-duty grades for extreme salt fog environments.

7. Wiring Standards

Two-wire transmitter wiring: Transmitter positive → FTA Ch+, transmitter negative → FTA Loop– (connected to shared ground bus); reversed polarity creates measurable PV offset and degraded HART waveform integrity.

Cable specification: Shielded twisted-pair instrument cable for all field wiring runs; cable shield grounded solely at DCS cabinet FTA side with field equipment end ungrounded to fully suppress ground loop noise.

Power cable segregation: Physically separate analog instrument cables from high-voltage AC power, MCC and VFD output wiring to minimize capacitive and inductive EMI coupling interference.

8. Incompatible Hardware

All isolated AI/AO FTAs (51304644, 51304640, 51304648, 51304650), non-isolated non-HART AI (51304672), non-isolated AO FTAs, discrete DI/DO termination boards, TC/RTD dedicated FTAs, pulse counter termination blocks and serial communication terminal assemblies cannot be paired with this non-isolated HART AI IOP card.