2. Model Definition

51304640: Base model for 16-channel galvanically isolated non-HART analog output FTA

-175: Mid-heavy reinforced industrial PCB grade

Medium-thick reinforced full-board conformal coating, superior humidity/dust/mild corrosion resistance vs -100/-150

High-capacity bidirectional TVS transient, ESD and wiring fault surge suppression per isolated channel

Three-stage cascaded RC EMI filter network for severe VFD/MCC high-noise plant zones

Independent per-channel galvanic isolation barriers to eliminate field-DCS ground loop circulating currents

Oversized reinforced freewheeling diode arrays for full inductive coil back-EMF dissipation

Precision tight-tolerance isolated current-damping resistors for perfectly matched 4–20mA linearity across all channels

Extra-thick reinforced physical channel isolation partitions to block inter-channel signal leakage and false cross-switching

Matched IOP Hardware: Honeywell 16-channel galvanically isolated non-HART 4–20mA analog output UCN IOP card

Incompatible Hardware: Isolated HART AO (51304516), non-isolated AO series, isolated/non-isolated AI FTAs, discrete DI/DO, TC/RTD LLAI, pulse counter, serial communication FTAs

3. Technical Specifications

Channel Count: 16 fully galvanically isolated non-HART 4–20mA analog output channels

Supported Field Loads

2-wire standard 4–20mA electro-pneumatic I/P transducers, conventional pneumatic valve positioners, air damper actuators

Resistive indicator lamps, small-to-medium inductive control coils (no HART communication capability)

FTA Structure: Passive isolated termination block; galvanic isolation barrier separates DCS IOP side and field load side; per-channel filtering, surge, kickback protection integrated

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

Terminal Type: Compression screw terminals, solid/stranded copper wire up to 14 AWG; each channel has independent isolated terminal pair

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

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

Circuit Architecture

Three-stage low-pass EMI filtering to suppress heavy switching noise from large VFD banks, motor control centers and medium-voltage switchgear

High-energy bidirectional transient overvoltage surge suppression on each isolated field output pair

High-power flyback diodes to eliminate large inductive coil back electromotive force voltage spikes

Galvanic isolation barrier eliminates ground potential offset errors between multi-grounded field equipment and DCS cabinet ground

Calibrated isolated damping resistors guarantee uniform actuator pull-in current and full-range linear stroke response

Thickened isolation partitions to eliminate inter-channel analog bleed and output drift interference

Redundancy Compatibility: Fully supports primary/standby redundant isolated non-HART AO IOP architecture; hot-swap IOP card replacement permitted

Approximate Unit Weight: 0.360 kg

4. Interface & Communication Configuration

Inner IOP Connection: Locking heavy-duty flat ribbon cable directly mates to isolated non-HART AO IOP pin headers. Reinforced cable strain relief prevents pin header deformation or fracture under long-term tension of field multi-core wiring harnesses. Isolated pure DC 4–20mA drive signals pass through galvanic barriers, three-stage filters and high-energy surge networks to field load terminals. The isolated AO IOP generates on/off analog setpoint drive logic, receives control commands from Experion PKS controller via UCN bus; no onboard signal amplification or logic processing.

Field Outer Terminals: Every channel features independent isolated Ch+ / Loop– terminals; field 24VDC load power circuit is fully galvanically separated from DCS control ground potential.

Drive Power Source: Regulated isolated 4–20mA drive power sourced exclusively from paired isolated non-HART AO IOP card through FTA passive protection networks.

5. Core Functions

Cable Strain Relief: Heavy-duty reinforced strain relief protects fragile isolated AO IOP pin headers from mechanical stress, bending and fatigue fracture caused by continuous pulling force of multi-core field control cables.

Three-Stage Advanced EMI Noise Rejection: Three-layer cascaded filter architecture outperforms single (-100) and dual-stage (-150) variants, fully eliminating valve hunting, output jitter and unstable actuator stroke in high-noise motor/VFD and power switchgear zones.

Reinforced Surge & Inductive Kickback Protection: High-capacity TVS clamping diodes absorb large induced voltage spikes, wiring short-circuit transients and switching arcs; oversized freewheeling diodes fully dissipate heavy coil back-EMF, robustly protecting sensitive isolated IOP output drive semiconductors.

Mid-Heavy Anti-Corrosion Environmental Barrier: Medium-thick reinforced conformal coating fully encapsulates PCB substrate, solder pads, copper traces and all passive components. Delivers stable 24/7 analog control under long-term elevated humidity, heavy dust accumulation and trace mild acidic/alkaline corrosive fumes.

Full Galvanic Ground Loop Elimination: Independent per-channel galvanic isolation completely stops circulating ground loop currents from differing field equipment and DCS cabinet ground potentials, solving unstable valve stroke common in multi-ground plant layouts.

Uniform Isolated Drive Consistency: Precision calibrated isolated damping resistors deliver identical drive strength, pull-in speed and linear stroke performance across all 16 channels for matched I/P and valve positioner operation.

Isolated Single-Channel Maintenance: Independent isolated terminal blocks support I/P/actuator replacement, full loop resistance/insulation testing and fault troubleshooting for one control loop without disrupting the other 15 critical process, safety and interlock output circuits.

Redundancy Hot-Swap Capability: Standby redundant isolated non-HART AO IOP cards can be replaced online without losing critical flow, pressure, level valve setpoints, safety trip relay drive signals or damper control outputs.

6. Application Scenarios

Applicable Industries

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

Isolated Non-HART Analog Control Loops

Conventional electro-pneumatic I/P transducers, standard pneumatic valve positioners, furnace draft air damper actuators, blending control valves, pressure reducing valve coils, cooling water flow control actuators, boiler feedwater modulating valve positioners.

Cabinet Deployment

Dedicated compact slot for 16-point mid-heavy isolated non-HART analog output inside high-density space-saving critical DCS I/O control cabinets for moderately harsh cabinet atmospheres.

7. Wiring, Operation & Maintenance Guidelines

Wiring Standards

Load wiring: Connect actuator/I/P positive to isolated FTA Ch+, load negative to isolated Loop–; reversed polarity degrades kickback diode performance and accelerates component aging.

Deploy shielded twisted-pair multi-core control cable for all field runs; implement single-point shield grounding only at DCS cabinet FTA side to eliminate ground loop noise and valve hunting.

Route isolated AO analog cables physically separated from high-current AC power, MCC and VFD output wiring to minimize EMI coupling interference.

Spare Part Interchangeability

51304640-175 shares identical isolated non-HART analog output core circuit topology with -100/-150/-200 variants, fully electrically interchangeable for emergency field substitution. The -175 mid-heavy reinforced grade is selected for cabinets with obvious high humidity, heavy dust or trace corrosive gas where -100/-150 lack long-term stability margin, at lower cost than full heavy-duty -200/-250 units.

Standard Fault Troubleshooting Flow

Valve hunting / no actuator stroke / saturated output / unstable PV → Retighten compression terminal screws → Measure isolated 24VDC loop drive current at load terminals → Test actuator/I/P coil continuity and insulation resistance → Inspect wiring for opens/shorts or moisture ingress → Confirm ribbon cable fully locked into isolated non-HART AO IOP header → Diagnose operational health of paired isolated AO IOP card.