Honeywell 8C-TDODA1 32-Ch 24VDC Sourcing DO IOTA Termination Assembly

Core Definition & Distinction

Model Code Meaning

• 8C: PCB conformal coated (G3 anti-corrosion coating, suitable for chemical/refinery corrosive cabinets)
• TDODA1: Non-redundant 9-inch IOTA terminal board for 32-channel sourcing digital output
• Matching redundant version: 8C-TDODB1 (12-inch redundant IOTA base)
• Part number: 51307149-175

1. Key Electrical Parameters

• Total channels: 32 independent 24VDC sourcing digital outputs
• Output type: Sourcing (source positive 24VDC to field loads)
• Single channel max load: 100mA (0.1A); total module max load 3.2A
• Rated field voltage: 24VDC, maximum allowable load voltage 30VDC
• Galvanic isolation: 1000VAC channel-to-backplane isolation, eliminate ground loop interference
• Off-state leakage current ≤5μA; switch response time ≤10ms
• Power consumption of IOTA base: ~105mA
• Per-channel independent short-circuit & overcurrent protection

2. Hardware & Wiring Structure

1. Terminal Design
    
   Dense screw compression terminal blocks, clearly labeled D01~D32 channel numbering; bussed field power distribution design to simplify external 24VDC wiring.
2. Interface Connection
    
   Upper dedicated ribbon cable connector to plug into 8C-PDODA1 logic module; two auxiliary power plug terminals for external field 24VDC power supply.
3. Diagnostic Indicators
    
   On-board green LED group for channel status feedback, quickly judge output on/off state and wire break fault.
4. Mechanical Specs
   • Form factor: Standard 9-inch single-slot Series 8 rack mounting
   • Net weight: ~1.0kg
   • Protection grade: IP20 (indoor control cabinet only)
   • Hot-swap support: Online replaceable without powering down the entire rack

3. Environmental & Reliability

• Operating temperature: 0℃ ~ +60℃; storage -40℃ ~ +85℃
• Humidity: 5%–95% RH non-condensing
• PCB conformal coating: Resist moisture, dust, chemical vapor, salt fog for coastal/refinery sites
• Certifications: CE, UL, CSA industrial safety compliance

4. Core Matching Combination

1. Logic control card: 8C-PDODA1 (backplane communication, execute DCS output logic)
2. Wiring terminal base: 8C-TDODA1 (field cable termination, power distribution, isolation circuit)
    
   One-to-one paired installation on C300 Series 8 I/O rack.

5. Main Functions

1. Physical wiring interface between DCS control module and field discrete equipment
2. Distribute isolated 24VDC sourcing switching signals to drive:
   • Solenoid valves, pneumatic actuator coils
   • Auxiliary small relays, motor starter control coils
   • On-site alarm lights, audible buzzers, local interlock switches
3. Per-channel open-circuit/short-circuit fault detection, upload abnormal status to Experion operator station
4. Support FAILOPT fail-safe configuration: define channel output state when communication fails

6. Key Advantages

1. 32-channel high-density layout, greatly reduce rack slot occupation for multi-point discrete control
2. Integrated field isolation circuit, stable signal under strong EMI from inverters and large motors
3. Conformal coated circuit board, suitable for harsh petrochemical, power plant environments
4. Separated IOTA terminal base, replace wiring board without removing core logic module
5. Centralized bus power terminals, simplify cabinet field power wiring layout

7. Typical Application Scenarios

• Petrochemical refinery, natural gas plant pipeline valve on/off control
• Thermal power boiler, turbine auxiliary equipment interlock logic
• Chemical reactor batch production sequence control
• Water treatment pump, fan, dosing valve switching control
• All continuous production DCS systems based on Honeywell Experion PKS C300 controller