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Honeywell 8C-TDILA1
Product Name: Series 8 Non-Redundant 32-Channel 24 VDC Digital Input IOTA (G3 coated)
Product Introduction: The 8C-TDILA1 (part number 51307141-175) is a high-density digital input termination assembly within the Honeywell Experion PKS Series 8 / C300 DCS family. It provides the physical wiring interface and mounting carrier for the 8C-PDILA1 digital input I/O module, supporting 32 channels of 24 VDC discrete input from field contacts such as push-buttons, limit switches, and motor-starter auxiliary contacts. The assembly features factory G3 conformal coating.
Detailed content
Technical Specifications:
- Product type: Non-redundant Digital Input IOTA (baseplate-integrated)
- Compatible I/O module: 8C-PDILA1
- Input channels: 32 digital inputs
- Input voltage rating: 24 VDC nominal
- DI power voltage range: 18–30 VDC (user-supplied field power)
- Module current: 95 mA
- Input type: Dry contact / 24 VDC voltage input
- ON sense: 13 VDC (min) or 3 mA (min)
- OFF sense: 5 VDC (max) or 1.2 mA (max)
- Input impedance: 4.2 kΩ
- Absolute delay across filter & isolation: 5 ms ± 20%
- Field resistance — guaranteed ON @ 15 VDC: 300 Ω max
- Field resistance — guaranteed OFF @ 30 VDC: 30 kΩ min
- Channel scanning (PV) — Normal mode: 20 ms
- Channel scanning (PV) — Low Latency mode: 5 ms
- SOE resolution: 1 ms
- Galvanic isolation: 1000 VAC RMS or ±1000 VDC (any input terminal to common); optical isolation technique
- Field power: Internal or external selectable
- Onboard excitation power: Yes (no marshalling power required)
- Input indication: Direct / Reverse configurable
- Hot-swap (RIUP): Supported
- Self-diagnostics: Extensive internal diagnostics for data integrity
- Operating temperature: 0 °C to +60 °C
- Storage temperature: -40 °C to +85 °C
- Operating modes: Normal / SOE / Low Latency (3-mode selectable)
- Agency certifications: Class I, Div. 2, Groups A/B/C/D, T4; Class I, Zone 2, AEx/Ex nA IIC T4
- Standards compliance: ISA, CE, UL, CSA, FM
- Weight: 0.65 kg
- Dimensions: 120 × 300 × 110 mm
- Terminal type: Screw compression terminals
- Redundancy: Non-redundant (this variant)
Functional Features:
- 32-channel single-ended interface with common return, maximizing wiring density
- G3 conformal coating resists H₂S, Cl₂, and other corrosive gases
- Three selectable operating modes: Normal, SOE (Sequence-of-Events), and Low Latency
- 1 ms SOE resolution for event timing capture
- Selectable internal/external field power; onboard excitation eliminates marshalling power requirement
- Direct/reverse input indication configurable
- Extensive self-diagnostics
- Hot-swap support for online maintenance without disturbing field wiring
Application Scenarios: Acquisition of discrete status signals — limit-switch positions, ESD valve feedback, motor-starter auxiliary contacts, push-button states — in process automation. Particularly suited to oil refineries and chemical processing plants where G3 corrosion protection is mandatory.
Structural & Material Characteristics: The IOTA is built on a G3-coated baseplate with screw compression terminals for 32 field wires, a multi-pin I/O module socket, and internal 24 VDC distribution bus. Its vertical form factor maximizes cabinet density. The board layout incorporates optical isolators for channel-to-system galvanic isolation.
Working Principle: Field contacts or 24 VDC voltage signals arrive at the screw terminals. The IOTA distributes 24 VDC excitation to the field contacts. The signal passes through input filtering and optical isolation before reaching the mated 8C-PDILA1 I/O module, which scans the channels at the configured rate (20 ms normal, 5 ms low-latency) and transmits state changes to the C300 controller. In SOE mode, state transitions are time-stamped with 1 ms resolution.
Installation Requirements:
- Mount on Series 8 carrier; insert 8C-PDILA1 into the IOTA socket
- Provide 18–30 VDC field power (internal or external selectable via IOTA wiring)
- Use fine-stranded wire with ferrules for all connections to compression terminals
- Clear labeling and organized wire ducting are essential to prevent cross-talk
- Ensure panel DC power is isolated before mounting
Usage Notes:
- This IOTA is non-redundant. For redundant 32-channel DI monitoring (two modules on the same field points), use the redundant IOTA variant 8C-TDILB1.
- Select operating mode (Normal / SOE / Low Latency) based on application timing requirements
- Configure FAILOPT and direct/reverse indication per channel as needed
- Periodically inspect coating integrity in highly corrosive atmospheres
