Component Snapshot At-a-Glance

• Model: 336A4940DNP508TX, OEM N-Tron 508TX, GE internal reference IS420ESWAH3A
• Alt. P/N: 336A4940DNP516TX (16-port variant, larger footprint, higher power draw, not direct drop-in)
• Product Series: GE Vernova Speedtronic Mark VI / Mark VIe gas & steam turbine control platform
• Hardware Type: DIN rail mount unmanaged industrial Ethernet switch, sealed metal convection-cooled chassis
• Key Feature: 8 galvanically isolated RJ45 ports, Class I Div 2 hazardous area certification, wide 10–30VDC control power input
• Primary Field Use: Star topology network hub for Mark VIe IONet, interconnects turbine controllers, remote I/O packs, HMIs and historian nodes inside control cabinets

Hard-Numbers: Technical Specifications

• Protocol Support: IEEE 802.3u 10/100Base-TX auto-negotiation, unmanaged layer 2 switching, IONet compatible
• Port Count: 8 × RJ45 copper ports, 1 terminal block DC power input
• Baud/Data Rate: 10 Mbps / 100 Mbps auto-sense per port, wire-speed packet forwarding
• Operating Temperature: -40°C to +85°C cabinet operational; -40°C to +85°C storage, non-condensing
• Isolation Rating: Each RJ45 port 1500VDC galvanic isolation to block cross-chassis ground loop noise
• Power Draw: 0.5A max at 24VDC nominal, 10–30VDC wide DC input range
• Cable Distance Limit: 100m max per port with CAT5e UTP/STP
• Certifications: Class I Div 2 Zone 2, UL, CE, T4 temperature rating
• Cooling: Passive convection, no internal fans
• Mechanical Mount: Standard 35mm DIN rail clip mount, aluminum alloy enclosure

The Real-World Problem It Solves

Consumer-grade office switches lack port isolation and hazardous area ratings; VFD EMI creates packet loss, broken IONet communication, and frozen turbine HMI screens in turbine cabinets.Smaller 5-port industrial switches run out of ports on full-size Mark VIe racks, forcing daisy-chained I/O packs that introduce single points of network failure.Separate DIN rail power terminals add loose vibration-prone wiring taps; this unit accepts standard 28VDC rack control power direct from IS200JPDHG1AAA distribution cards.Where you’ll typically find it:

• Combined cycle power plant Mark VIe gas turbine main control cabinets, star hub for TMR controllers and vibration/temperature I/O packs
• Refinery compressor turbine DCS racks for SIL-rated ESD safety I/O and plant historian data links
• Cogeneration boiler turbine remote I/O panels fed by 342A4922P28V500DH 28V power suppliesThis 8-port isolated industrial switch eliminates consumer network hardware failures, fits standard turbine cabinet DIN rail layouts, and runs on native 28VDC control power without auxiliary power adapters.

Hardware Architecture & Under-the-Hood Logic

This unmanaged switch has no user-configurable CPU or software; it uses fixed layer 2 switching ASIC with isolated magnetics on every copper port.

1. 24–28VDC control power feeds internal EMI filter and isolated DC-DC converter, stabilizing supply voltage against rack power ripple from 342A4922P28V500DH power modules.
2. Discrete 1500V isolation transformers on each RJ45 port break ground loop paths between controller chassis and remote I/O field cabinets.
3. Fixed switching ASIC forwards Ethernet packets wire-speed without latency, no VLAN or ring management logic required for Mark VIe IONet star topology.
4. Passive convection cooling via top chassis ventilation slots dissipates low switching heat without fan noise or moving parts prone to dust clogging.
5. Front panel per-port link/activity LEDs provide instant visual fault identification for dead I/O pack or controller Ethernet runs.

Field Service Pitfalls: What Rookies Get Wrong

Swapping 16-port 336A4940DNP516TX as a direct cabinet replacement

The 16-port model draws higher continuous current and occupies extra DIN rail space; overloaded JPDH distribution channels trigger persistent fuse trips and low 28V rail voltage.

• Field Rule: Use 336A4940DNP508TX for standard Mark VIe racks with ≤7 network devices; reserve 16-port units only for large multi-turbine shared control rooms.

Running unshielded CAT5 office cable parallel to VFD and 480V power wiring

Unshielded cable picks up high-frequency switching noise, causing intermittent port flapping and missing turbine SOE fault event data on the HMI.

• Quick Fix: Run industrial shielded CAT5e cable; single-point ground shield only at the switch cabinet end, leave remote I/O cabinet shield floating to avoid dual ground loops.

Blocking top ventilation slots with cable bundles or blank filler plates

Trapped heat pushes internal temperature above +85°C threshold, triggering silent port isolation and random IONet communication dropouts with no visible fault alarm.

• Field Rule: Leave minimum 25mm clear vertical space above and below the switch; secure all cable harnesses away from chassis vent grilles.

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.