Description
Honeywell 8C-PAOHA1
Technical Specifications
- Channel count: 8 analog output channels
- Signal type: 4–20 mA DC current loop
- HART support: HART 5 master mode
- Resolution: 12-bit DAC
- Channel isolation: 500 VAC group isolation
- Backplane interface: C300 I/O subrack bus
- Maximum loop load: 500 Ω
- Operating temperature: 0 °C to +60 °C
- Hot swap support: Online card replacement
Functional Features Bidirectional HART communication, reads smart valve positioner feedback, travel percentage and diagnostic alerts. Per-channel short circuit protection, limits output current on field wiring faults. Output readback sampling, compares commanded output to actual loop current, triggers fault on mismatch. Configurable fail-safe output value on controller stop, places valves in safe position. Digital output filter smooths control signal variation. On-board LEDs indicate card power, communication and fault status.
Application Scenarios Smart control valve positioner drive loops Variable speed drive speed reference output Process flow and pressure control modulation Spare part replacement for HART analog output card faults C300 system process control loop integration
Performance Parameters
- Output accuracy: ±0.2% full scale
- Update rate: 10 ms per channel
- Short circuit current limit: 25 mA
- HART update rate: 500 ms per channel
- Mean time between failures: 550,000 hours
Material Composition FR4 flame retardant PCB substrate 12-bit DAC chip Output operational amplifier array HART modem circuit Group isolation optocouplers TVS protection diodes Gold-plated backplane edge fingers
Structural Features Standard C300 I/O card form factor. Front detachable terminal block for 8 channel output wiring. Isolation barrier separates field output side and backplane side. Front status LEDs show card run and fault. Anti-keying notch prevents mis-slot insertion.
Working Principle The C300 controller sends setpoint values over the subrack bus to the card. Each channel routes the value to a 12-bit DAC, converting digital commands to analog current signals. The HART modem superimposes digital signals on the 4–20 mA loop, communicating with connected smart positioners. Output readback samples actual loop current; deviation between command and measured value triggers a channel fault alarm. On controller stop, outputs default to the pre-configured fail-safe value.
Installation Requirements Insert the card into a dedicated analog output subrack slot. Wire smart positioners and actuators to labeled output terminals. Configure fail-safe output value and HART device settings in Control Builder software. Verify output current scales correctly from 4 mA to 20 mA during commissioning.
Usage Notes Loop load impedance must not exceed 500 Ω, higher impedance causes output voltage droop. Never short-circuit output terminals repeatedly; repeated short circuits damage the output driver. HART communication requires shielded twisted pair cable. Never apply external power to output terminals, reverse voltage destroys the DAC chip.
