Description
Hard-Numbers: Technical Specifications
- Protocol Support: Dual redundant IONet Ethernet
- Port Count: 2 × 100Mbps RJ45 IONet ports
- Output Channels: 12 isolated discrete outputs (dry contact)
- Output Rating: 24V DC, 0.5A per channel (max 6A total)
- Isolation Rating: 1500V rms field-to-backplane
- Response Time: 6 ms channel-to-channel update
- Operating Temperature: -40°C to +70°C
- Power Draw: 4.8 W typical
- Connector: 37-pin D-Sub field termination
- Environmental: G3 conformal coating, Class I Div 2 hazardous location rated
IS420YDOAS1B
The Real-World Problem It Solves
Unisolated digital output cards pass ground potential differences and induce cross-talk between field circuits. This causes intermittent relay chatter and false trip signals in high-noise industrial cabinets.
Where you’ll typically find it:
- Gas/steam turbine emergency stop (ETS) logic racks
- Refinery process valve solenoid control panels
- Combined-cycle plant auxiliary system interlock circuits
Bottom line: It eliminates ground-loop faults and stabilizes binary control signals in electrically harsh power and process environments.
Hardware Architecture & Under-the-Hood Logic
This pack uses an onboard BPPC microprocessor for local command execution, reducing controller bus loading. Each output channel has independent optical isolation and solid-state drive circuitry.
- Control commands arrive via redundant IONet Ethernet to the onboard processor.
- Processor validates command integrity and routes signals to output driver stages.
- Isolation barriers block common-mode voltage and electrical noise from field wiring.
- Solid-state switches energize field relays/valves; per-channel LEDs confirm ON state.
- Output status and fault data feed back to the controller for diagnostics.
Field Service Pitfalls: What Rookies Get Wrong
Overloading Single Output ChannelsTechs exceed 0.5A per channel by driving high-inrush contactors. This burns internal driver FETs and causes dead channels with no fault indication.
- Field Rule: Use interposing relays for loads >0.5A; never exceed 6A total module current.
Incorrect Power Polarity on Field TerminationsReversing 24V DC polarity on output circuits locks channels in OFF state. No fault log records the wiring error—only dark LEDs.
- Quick Fix: Verify 24V+ to terminal +V, 0V/common to GND; label field wiring before connection.
Mixing Revision Levels in TMR RacksInstalling alongside older YDOA revisions creates mismatched voting logic. This triggers intermittent “output discrepancy” faults.
- Field Rule: Maintain identical hardware revisions across all three TMR I/O packs; check suffix codes before installation.
IS420YDOAS1B
Commercial Availability & Pricing Note
Please note: The listed price is for reference only and is not binding. Final pricing and terms are subject to negotiation based on current market conditions and availability.
