Honeywell HC900 Modules: 8C-TAOX61/51306981-175 Analog Output Module

Technical Dossier

Product Details And Specifications

Honeywell HC900 Series Technical Notes

The Honeywell HC900 Hybrid Controller is a distributed control system (DCS) platform deployed extensively across global heavy industry, including petrochemical refineries, chemical processing plants, power generation facilities, and offshore platforms. Its modular rack-based architecture supports mixed analog/digital I/O, redundant CPU configurations, and peer-to-peer Ethernet communication, making it a long-cycle asset in facilities where replacement of the entire control system is cost-prohibitive. The HC900 occupies a critical position in the installed base of process automation infrastructure, with thousands of active installations requiring ongoing spare parts support.

The Evolution of HC900 Architecture

The HC900 platform was introduced by Honeywell as a hybrid controller bridging traditional PLC discrete logic and DCS continuous process control. Early revisions used proprietary backplane communication at fixed baud rates with limited peer networking. Subsequent hardware generations introduced dual-redundant CPU modules (8C-PCNT0x series), expanded the I/O module count per rack, and migrated the supervisory interface to Ethernet/IP. The 8C- module prefix denotes the HC900 I/O family, distinguishing it from the legacy HC-900 rack components. Compatibility between hardware revisions requires attention to firmware version alignment: older I/O modules may not initialize correctly under later CPU firmware without a configuration database migration. As the HC900 platform has entered its mature/end-of-active-development phase, Honeywell's primary support posture is sustaining engineering — new installations are directed toward the Experion PKS platform. This makes long-term spare parts availability from specialist distributors a critical operational requirement for existing HC900 sites.

HC900 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked HC900 module types. Each entry reflects a distinct functional role within the HC900 rack architecture.

Analog Output Modules

• 8C-TAOX61/51306981-175: 6-channel 4–20 mA analog output, HART-capable, isolated
• 8C-TAOX11/51306980-175: 1-channel analog output, 4–20 mA, non-isolated
• 8C-TAOX21/51306982-175: 2-channel analog output, 4–20 mA, isolated per channel

Analog Input Modules

• 8C-TAIX51/51306983-175: 8-channel analog input, 4–20 mA / 1–5 V, HART pass-through
• 8C-TAIX11/51306984-175: 4-channel analog input, thermocouple/RTD universal
• 8C-TAIX31/51306985-175: 16-channel analog input, single-ended, 4–20 mA

Digital Input Modules

• 8C-TDIL01/51306986-175: 32-channel 24 VDC digital input, sink/source configurable
• 8C-TDIL11/51306987-175: 16-channel 120 VAC digital input, optically isolated
• 8C-TDIL21/51306988-175: 16-channel 24 VDC digital input, high-speed pulse capable

Digital Output Modules

• 8C-TDOB01/51306989-175: 32-channel 24 VDC digital output, transistor sourcing
• 8C-TDOB11/51306990-175: 16-channel relay output, Form C contacts, 2 A per channel
• 8C-TDOB21/51306991-175: 8-channel high-current relay output, 5 A per channel

CPU / Controller Modules

• 8C-PCNT01/51306992-175: HC900 primary CPU module, 256 MB memory, Ethernet supervisory port
• 8C-PCNT02/51306993-175: HC900 redundant CPU module, hot-standby failover, matched firmware required

Communication & Power Modules

• 8C-CPNT01/51306994-175: Remote I/O communication adapter, fiber optic, 100 Mbps
• 8C-PWR01/51306995-175: HC900 rack power supply, 24 VDC input, 40 W output
• 8C-PWR02/51306996-175: HC900 redundant power supply module, hot-swap capable

Quality Control for the HC900 Range

HC900 modules present specific test challenges due to their backplane-dependent initialization sequence and HART communication layer. DriveKNMS applies the following test protocol to all HC900 modules prior to shipment: bench power-up verification against HC900 rack backplane at rated voltage; functional I/O channel scan using calibrated signal sources (4–20 mA loop calibrator for analog modules, 24 VDC switching for digital modules); HART device descriptor polling on HART-enabled analog output modules including the 8C-TAOX61; firmware version readback and logging; and visual inspection of backplane connector pins, conformal coating integrity, and capacitor condition. Modules that fail any stage are quarantined and not returned to inventory.