Product Overview
The Honeywell 8C-TDIL11 (51306858-175) is a 32-channel, 24 VDC digital input module and input/output termination assembly, or IOTA, for Honeywell Experion PKS Series C and C300 control architectures. It acquires discrete on/off signals from limit switches, pushbuttons, relay contacts, motor-starter auxiliary contacts, proximity sensors, valve-position switches, and emergency-stop or interlock contacts. The conditioned signals are transferred to the C300 controller through the Series C I/O backplane, providing reliable state information for interlocking, sequencing, alarms, and event analysis.
The Honeywell 8C-TDIL11 is distinguished by its combination of high channel density, redundant-IOTA capability, and sequence-of-events functionality. It supports three operating modes: normal mode with a 20 ms process-variable scan, low-latency mode with a 5 ms scan, and SOE mode with 1 ms event-resolution time-tagging. These characteristics make the Honeywell 8C-TDIL11 51306858-175 suitable for applications where engineers must determine the exact order of trips, valve movements, contactor operations, or safety-related state changes.
A key architectural advantage is that redundancy is implemented at the IOTA level. Two input I/O modules can occupy one IOTA, allowing the control system to maintain signal acquisition when a single IOM fails. The Honeywell 8C-TDIL11 provides galvanic isolation between field terminals and the system backplane, optical isolation within the IOM, onboard excitation power, and internal diagnostics. The “8C” prefix indicates a corrosion-resistant coating for demanding control-room and enclosed-cabinet environments; the uncoated equivalent is 8U-TDIL11.
Because the module is part of a mature platform, replacement requires exact verification of the IOTA kit number, module revision, controller firmware, termination type, field-power selection, and project configuration. The Honeywell 8C-TDIL11 51306858-175 is therefore a strategic spare for maintaining system availability, but it is not a universal 24 VDC input device.
Technical Specifications
| Parameter | Value |
|---|---|
| Product Model | 8C- |
| Assembly/Order Reference | 51306858-175 |
| Manufacturer | Honeywell |
| Product Type | Digital input IOTA / digital input board |
| Platform | Honeywell Experion PKS Series C, Series 8, C300 I/O |
| Input Channels | 32 |
| Nominal Input Voltage | 24 VDC |
| Input Voltage Range | 18–30 VDC |
| Guaranteed ON Threshold | ≥13 VDC or ≥3 mA |
| Guaranteed OFF Threshold | ≤5 VDC or ≤1.2 mA |
| Input Impedance | 4.2 kΩ |
| Field Resistance, Guaranteed ON | ≤300 Ω at 15 VDC |
| Field Resistance, Guaranteed OFF | ≥30 kΩ at 30 VDC |
| Normal PV Scan Period | 20 ms |
| Fast/Low-Latency PV Scan | 5 ms |
| SOE Resolution | 1 ms |
| Absolute Input Delay | 5 ms ±20% |
| Galvanic Isolation | 1500 VAC RMS or ±1500 VDC |
| Isolation Method | Optical isolation in IOM |
| Field Power Selection | Internal or external |
| Excitation Power | Onboard, non-incendive field power |
| Diagnostics | Open wire, short circuit, module health, communication and power faults |
| Redundancy | Optional 1:1 redundant IOM on one IOTA |
| Hot-Swap Capability | Yes, in supported redundant configuration |
| Operating Temperature | 0 °C to +60 °C for standard control environment; coated assembly supports extended-temperature documentation in some Series 8 references |
| Storage Temperature | -40 °C to +85 °C |
| Relative Humidity | 5% to 95%, non-condensing |
| Protection Rating | IP20, cabinet/enclosure mounted |
| Dimensions | 51 × 267 × 178 mm |
| Weight | Approximately 0.5 kg |
| Certifications | CE, UL, CSA, ATEX/IECEx where system and marking permit |
