Product Overview

The Honeywell 8C-TDOD51 (Order Code: 51306975-175) is a high-density digital output module engineered for the Experion® Process Knowledge System (PKS) and Series C/C300 distributed control platform. As a core component of the Honeywell Series C I/O family, this module translates controller logic commands into physical switching signals to drive field actuators including solenoid valves, motor contactors, pilot relays, and alarm indicators. The Honeywell 8C-TDOD51 ensures reliable execution of discrete control strategies in mission-critical industrial processes.

The Honeywell 8C-TDOD51 is available in multiple channel configurations and output types to suit diverse application requirements. Depending on the specific variant, the module provides 8, 16, or 32 channels of digital output with either relay contacts or transistor sinking/sourcing outputs. The relay output variant of the Honeywell 8C-TDOD51 features Form C (SPDT) contacts rated at 2A per channel, supporting both AC and DC load switching without additional interposing relays. The transistor output variant delivers fast 24V DC switching with response times under 1 ms for high-speed sequencing applications. All versions of the Honeywell 8C-TDOD51 feature full galvanic isolation (up to 2500V) between field circuits and the control backplane, protecting sensitive system electronics from field wiring faults and electromagnetic interference. The module’s intelligent diagnostic capabilities include per-channel open circuit detection, short circuit protection, and overcurrent monitoring, with fault status communicated directly to the DCS operator console for rapid troubleshooting.

 

Technical Specifications

Parameter Name	Value
Product Model	Honeywell 8C-TDOD51
Order Number	51306975-175
Manufacturer	Honeywell Process Solutions
Product Type	Digital Output Module / IOTA Module
System Platform	Experion PKS, Series C, C300 Controller
Channel Count	8 / 16 / 32 (depending on variant)
Output Type	Relay (SPDT Form C) or Transistor (SINK/SOURCE)
Contact Rating (Relay)	2A @ 30V DC / 2A @ 250V AC (resistive)
Output Current (Transistor)	0.5A per channel (0.1A for 32-channel variant)
Voltage Range	24V DC (18-32V DC) / 125V AC/DC (relay variant)
Isolation	2500V RMS channel-to-backplane
Response Time	≤10 ms (relay), ≤1 ms (transistor)
Operating Temperature	-40°C to +70°C
Storage Temperature	-40°C to +85°C
Power Consumption	<3W (typ.), 150mA @ 24V DC
Dimensions	12 cm × 7 cm × 5 cm (8-channel) / Standard Series C form factor
Weight	0.24 kg – 0.7 kg (depending on variant)
Protection Rating	IP20 (cabinet installation)
Coating	G3 Conformal Coating (8C variant)
Approvals	CE, UL, CSA, Class I Division 2, TÜV SIL 3

 

Main Features and Advantages

Relay Output with High Load Capacity:
The Honeywell 8C-TDOD51 relay output variant provides 16 channels of SPDT (Form C) contacts rated at 2A per channel, capable of switching both 30V DC and 250V AC loads. This high current capacity enables direct control of solenoid valves, motor starters, and other inductive loads without requiring external interposing relays. The mechanical contact design eliminates leakage current concerns common with solid-state outputs, ensuring reliable operation in safety-critical applications. The Honeywell 8C-TDOD51 relay contacts are fully field-replaceable, extending module service life and reducing maintenance costs.

Channel-to-Channel Galvanic Isolation:
Every output channel on the Honeywell 8C-TDOD51 is electrically isolated from the system backplane and from other channels with a rating of 2500V RMS. This comprehensive isolation architecture prevents fault propagation: a short circuit or overvoltage condition on one field device will not affect other channels or the controller itself. The Honeywell 8C-TDOD51 maintains stable operation in high-EMI environments, including installations near variable frequency drives and heavy switchgear. This isolation capability is essential for maintaining system integrity in SIL-rated safety instrumented functions.

Intelligent Diagnostics and Status Monitoring:
The Honeywell 8C-TDOD51 incorporates per-channel diagnostic intelligence that continuously monitors output state, current draw, and contact health. Built-in open circuit detection, short circuit protection, and overcurrent monitoring alert operators to field wiring issues before they escalate into process disruptions. Each channel on the Honeywell 8C-TDOD51 features individual LED status indicators that provide immediate visual confirmation of output state and fault conditions. When used in redundancy configurations, the Honeywell 8C-TDOD51 supports bumpless switchover with zero output gap, ensuring continuous operation during module replacement.

Hot-Swap and Redundancy Support:
The Honeywell 8C-TDOD51 is designed for live insertion and removal in active control systems. Maintenance personnel can replace a faulty module without powering down the I/O rack or interrupting process operations. For applications requiring the highest availability, the Honeywell 8C-TDOD51 supports 1:1 hardware redundancy with automatic switchover between primary and backup modules. The module’s fail-safe architecture ensures outputs transition to predefined safe states in the event of communication loss or internal fault detection.