Component Snapshot At-a-Glance
- Model: 8306A
- Alt. P/N: No direct OEM cross; 8301A is mainframe DC PSU, pinout and output curve differ, cannot blind field swap into remote expansion rack
- Product Series: Triconex Tricon SIL3 TMR RXM remote expansion rack power family
- Hardware Type: Hot-swappable rack mount DC-DC switching supply built exclusively for 8111/8112 remote I/O chassis
- Key Feature: Tuned output rail regulation optimized for long cable-induced voltage drop on field-mounted remote racks
- Primary Field Use: Converts field 24VDC UPS feed into stabilized backplane DC rails to power all remote rack DI/DO/AI/AO modules.
Hard-Numbers: Technical Specifications
- DC Input Range: 20VDC ~ 30VDC nominal 24V industrial field source
- Max Continuous Output Rating: 85W steady rated at 60°C ambient, linear thermal derate above threshold
- Internal Output Rails: +5V, +24V, ±12V fixed regulated backplane outputs
- Isolation Rating: 2000VDC dielectric isolation between input field wiring and internal secondary output circuitry
- Operating Temperature: -20°C ~ +70°C continuous run; -40°C ~ +85°C non-operational storage
- Typical Idle Power Draw: 9W from 24VDC input source
- Hot-Swap Status: Full live hot-swap permitted on powered remote expansion rack without remote I/O faulting
- Fault Output: Form-C dry contact rated 24VDC/1A for remote cabinet fault alarm routing to central DCS
- Safety Certification: IEC61508 SIL3, UL Class I Div2, ATEX Zone2 hazardous location certified
The Real-World Problem It Solves
Standard 8301A mainframe PSU lacks voltage compensation for long field wiring runs; remote rack cable resistance causes low-side voltage sag and intermittent analog channel dropouts on field-mounted I/O. Generic third-party DC supplies have no matched load sharing, single unit failure cuts entire remote safety rack offline instantly.
Where you’ll typically find it:
- Refinery FCC field-mounted explosion-proof RXM racks positioned hundreds of meters from central control room SIS mainframe
- Coal plant boiler BMS remote I/O cabinets installed outdoors near furnace draft fan and fuel valve field equipment
- Onshore gas compressor station field HIPPS racks set inside process hazardous area buildings
Rail tuning for field cable loss eliminates costly intermediate local UPS setup for distant remote SIS I/O installations.
Hardware Architecture & Under-the-Hood Logic
No embedded onboard microcontroller; all DC conversion and passive load-sharing built with discrete analog PWM circuits calibrated for field remote rack load characteristics.
- Incoming site 24VDC first passes EMI choke and surge suppression components to block VFD and field motor switching noise.
- Isolated DC-DC transformer splits filtered input into three separate regulated output branches for independent backplane voltage control.
- Per-rail OVP/OCP protection cuts only faulty output instead of full module shutdown during single channel short events.
- Edge interlock pins enable passive automatic load balancing between paired redundant 8306A without external jumper wires.
- Internal NTC thermistor reduces output power progressively above 58°C core temperature to slow electrolytic capacitor degradation in sealed field cabinets.
- Front panel LED mapping: solid green = all rails nominal; amber = thermal derate active; red = full fault with remote alarm contact open.
Field Service Pitfalls: What Rookies Get Wrong
Blind Replacement With Main Chassis 8301A DC SupplyNew maintenance staff swap 8301A into remote rack 8306A slot. Output voltage profile mismatches remote rack load curve leading to chronic under-voltage and random remote I/O communication loss.
- Field Rule: Label all remote rack power slots exclusively for 8306A; store 8301A spares only for central main SIS chassis use.
Dual Redundant Units Tied To Single 24V Source FeedTechnician runs both redundant 8306A input cables off one shared UPS branch. Single source fuse blow takes both power supplies down and forces full remote rack shutdown.
- Quick Fix: Route each 8306A input from electrically isolated separate 24VDC UPS distribution circuits per site design specs.
Input Wiring Run Parallel Alongside Field 480V Motor Power TraysField installers route unshielded 24V input cabling next to high-current three-phase motor conduit. Induced AC ripple distorts DC feed and triggers intermittent PWR FAULT blink during large compressor startup spikes.
- Field Rule: Separate all 24VDC supply wiring minimum 30cm away from high voltage power cables; add ferrite clamp on input terminal for high EMI field cabinets.
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.
