2. Model Definition

51304728: Base model for 16-channel galvanically isolated HART analog output FTA

-125: Mild reinforced PCB protection grade

Medium-upgraded full-board conformal coating with improved resistance to humidity, dust and weak corrosive vapors versus -100 baseline

Moderate high-energy bidirectional TVS transient, ESD and line fault surge protection with per-channel isolation

Dual-stage cascaded RC differential EMI filter precisely tuned to retain full HART carrier amplitude without attenuation

Independent galvanic isolation barrier for each channel, no shared ground between field and DCS sides

Reinforced capacity flyback freewheeling diode arrays to fully dissipate back-EMF spikes from inductive actuator coils

Precision calibrated series damping resistors for uniform 4–20mA linear stroke response across all channels

Thickened plastic channel baffles to reduce inter-channel analog and HART signal crosstalk & leakage

3. Technical Specifications

Channel Count: 16 fully independent channels, complete galvanic isolation per loop

Compatible Field Devices

Two-wire HART smart valve positioners, electro-pneumatic HART I/P transducers, linear/rotary HART modulating actuators

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

FTA Structure: Passive isolated termination board with no internal power supply; integrated per-channel HART coupling, dual-stage differential filtering, medium-energy surge protection and heavy inductive kickback suppression

PCB Protection: Medium-upgraded conformal coating; flammability UL94 V0

Terminal Type: Compression screw terminals for solid/stranded copper wire up to 14 AWG; each channel has isolated Ch+ / Loop– field terminals separated from DCS ground

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

Operating Ambient: 0℃ ~ +60℃ indoor control cabinet; wider tolerance for humidity, dust and weak corrosion compared to -100; not rated for continuous salt fog or strong corrosive chemical fume environments

Circuit Architecture Parameters

Dual-stage low-pass differential filtering suppresses medium-level EMI from medium VFD and MCC loads while preserving intact HART waveform

Medium-energy bidirectional TVS clamps positive/negative transient high voltage on every isolated output loop

Per-channel galvanic isolation eliminates measurement drift and HART dropouts caused by field-to-DCS ground potential differences

Tight-tolerance damping resistors eliminate minor valve hunting and stabilize full-range 4–20mA linearity

Reinforced flyback diodes rapidly absorb large back-EMF generated by heavy inductive actuator coils

Thickened baffles minimize inter-channel analog bleed and cross-channel HART signal interference

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

Approximate Unit Weight: 0.359 kg

4. Interface & Communication Configuration

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

Field Outer Terminals: 16 groups of independent isolated Ch+ / Loop– terminals; each loop is electrically separated from DCS control ground and other channels.

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

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

5. Core Functions

Per-channel galvanic isolation: Eliminates ground loop interference, stable operation for multi-ground plant layouts.

Dual-stage medium EMI noise suppression: Reduces moderate electromagnetic interference from VFD and MCC equipment to eliminate valve hunting, setpoint drift and frequent HART poll retries.

Medium-strength surge & inductive kickback protection: Absorbs larger wiring transients and switching arcs to protect sensitive IOP output power semiconductors and field actuators from surge damage.

Uniform linear output performance: Precision matched passive components deliver consistent valve stroke response and stable HART handshake across all 16 channels to reduce bulk calibration workload.

Balanced inter-channel signal isolation: Thickened partition baffles restrain analog and HART crosstalk between adjacent control loops.

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

6. Application Scenarios

Applicable Industries

General petrochemical auxiliary zones, medium chemical plants, standard power plant auxiliary control, municipal wastewater treatment, mild-humidity pharmaceutical batch production lines

Typical Control Loops

General process throttle/shutoff HART smart valve positioners

Furnace & ventilation damper HART I/P transducers

Blending loop modulating HART actuators

Pressure reduction HART control valves

Utility system conventional I/P mixed with HART smart positioners

Fit for multi-ground and single-ground plant layouts, medium-noise VFD process zones, cabinets with mild elevated humidity and moderate dust accumulation, atmospheres with low-concentration weak acid/alkaline volatile vapors. Not applicable for continuous salt fog or heavy corrosive chemical workshop cabinets.

7. Wiring Standards

Two-wire actuator wiring: Actuator positive → isolated FTA Ch+, actuator negative → FTA Loop–; reversed polarity weakens kickback suppression efficiency and degrades 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 suppress residual 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

Non-isolated AI/AO FTAs (51304718, 51304685, 51304672, 51304690), isolated HART AI (51304644), isolated non-HART AI (51304650), isolated non-HART AO (51304640), discrete DI/DO termination boards, TC/RTD dedicated FTAs, pulse counter termination blocks and serial communication terminal assemblies cannot be paired with this isolated HART AO IOP card.