2. Model Definition

51304718: Base model for 16-channel non-isolated HART analog output FTA

-375: Extreme heavy-duty top-level reinforced PCB protection grade

Multi-layer marine-grade full-board conformal coating with industry-leading resistance to extreme humidity, conductive heavy dust, severe corrosive chemical vapors and continuous salt fog

Multi-tier composite ultra-high-energy bidirectional surge absorption stack (TVS+fast transient absorber+gas discharge auxiliary), far higher transient withstand energy than -325 and all lower grades

Three-stage fully symmetrical cascaded RC differential EMI filter, precision calibrated for ultra-high-noise heavy industrial zones with massive VFD clusters, full MCC banks and medium-voltage switchgear, zero attenuation and zero distortion to HART FSK carrier waveform

Global unified common ground bus for all 16 channels; no independent galvanic isolation barriers between individual output loops

Oversized high-current reinforced flyback freewheeling diode arrays to fully dissipate extreme back-EMF spikes from extra-large inductive heavy-load actuator coils

Ultra-precision ultra-tight tolerance series damping resistors for perfectly uniform full-range 4–20mA linear stroke response across all 16 channels

Extra-wide ultra-thick flame-retardant reinforced plastic channel partition baffles to completely eliminate inter-channel analog leakage and HART signal crosstalk

3. Technical Specifications

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

Compatible Field Devices

Two-wire critical heavy-duty HART smart valve positioners, ultra-high-load electro-pneumatic HART I/P transducers, oversized linear/rotary HART modulating actuators

Backward compatible with conventional non-HART 4–20mA pneumatic positioners and standard I/P converters

FTA Structure: Passive non-isolated termination board with no internal power supply; integrated per-channel low-distortion HART coupling, three-stage symmetrical differential filtering, multi-tier ultra-high-energy surge protection and extreme heavy inductive kickback suppression

PCB Protection: Multi-layer marine reinforced conformal coating; flammability UL94 V0

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

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

Operating Ambient: 0℃ ~ +60℃ indoor control cabinet; best-in-class tolerance for extreme humidity, conductive heavy dust, severe corrosion and continuous coastal salt fog among the series; still not suitable for multi-ground plant layouts (isolated FTA required for multi-ground sites)

Circuit Architecture Parameters

Three-stage symmetrical low-pass differential filtering suppresses extreme industrial EMI without distorting HART waveform or 4–20mA analog drive amplitude

Multi-tier composite bidirectional surge stack clamps positive/negative extreme transient high voltage on every shared-ground output loop

Shared common ground design; ground potential discrepancies between field and DCS will still induce slight stroke drift and minor HART instability

Ultra-tight precision tolerance damping resistors completely eliminate valve hunting and stabilize full-span 4–20mA linear output performance

Oversized high-current flyback diodes rapidly absorb extreme back-EMF energy generated by extra-large heavy inductive actuator coils

Ultra-thick flame-retardant baffles fully block inter-channel analog bleed and cross-channel HART signal interference

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

Approximate Unit Weight: 0.365 kg

4. Interface & Communication Configuration

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

Field Outer Terminals: Independent Ch+ / Loop– terminals for each two-wire actuator loop; all loops reference one unified ground bus matched to DCS control ground potential.

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

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 mixed HART/standard heavy-load actuator drive: Cost-effective single-ground layout supporting mixed deployment of critical heavy-duty HART smart actuators and conventional non-HART 4–20mA loads within the same cabinet.

Three-stage symmetrical ultra-heavy EMI noise rejection: Suppresses extreme intense electromagnetic interference from large VFD systems, MCC banks and medium-voltage switchgear to eliminate valve hunting, severe setpoint fluctuation and frequent HART communication retries.

Multi-tier ultra-high-energy surge & short-circuit fault protection: Withstands lightning-induced line transients, high-magnitude equipment startup surges and field short-circuit high voltage to protect expensive sensitive IOP output power semiconductors and critical heavy-duty field actuators.

Extreme heavy-duty uniform inductive load protection: Oversized flyback diode arrays evenly safeguard all channels from coil back-EMF damage for uninterrupted long-term critical process operation.

Consistent channel linearity & stable HART synchronization: Ultra-precision matched passive components deliver identical valve stroke response and reliable HART handshake across all 16 channels to reduce bulk calibration workload.

Redundant hot-swappable operation: Seamlessly synchronizes with primary/standby IOP switching logic; single-channel disconnection and troubleshooting do not impact operation of remaining 15 critical control loops.

6. Application Scenarios

Applicable Industries

Overseas offshore platforms, coastal refineries, large integrated petrochemical complexes, heavy-duty chemical synthesis plants, combined heat & power generation stations, massive oil & gas refineries, pulp & paper mills, high-humidity industrial wastewater treatment, heavy-batch pharmaceutical manufacturing lines, coastal chemical storage facilities

Typical Control Loops

Critical emergency safety shutoff system extreme heavy-duty HART smart valve positioners

High-pressure large-flow process throttle HART modulating actuators

Oversized furnace draft air damper ultra-high-load HART I/P transducers

High-volume process blending control valve heavy smart HART positioners

High-pressure reduction large modulating HART actuators

Ideal for single-ground plant layouts, ultra-dense VFD heavy-noise process areas, cabinets with persistent extreme high humidity and heavy conductive dust accumulation, atmospheres containing severe acidic/alkaline volatile vapors, offshore platforms and coastal sites with continuous heavy salt fog exposure. Not suitable for multi-ground plant layouts (must select isolated FTA models for multi-ground systems).

7. Wiring Standards

Two-wire actuator wiring: Actuator positive → FTA Ch+, actuator negative → FTA Loop– (shared ground bus); reversed polarity reduces kickback suppression efficiency and impairs HART waveform integrity.

Cable specification: Marine-grade heavy-duty 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 HART analog control 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 HART AI (51304685), non-isolated non-HART AI (51304672), non-isolated non-HART AO (51304690), 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 AO IOP card.