Application Scenarios:
A 3,800 t/d cement plant in Southern China still runs its kiln inlet / preheater / cooler sequencing on a S5-155U central rack (18 slots, CPU 948) commissioned in 1997. By 2018 the rack was full — 12 SM321/322 DI/DO, 4 SM331/332 AI/AO, 1 CP443, 1 FM355 — and the plant wanted to add a secondary bag-filter pressure-loop and a new stack-draft PID without touching the central rack’s proven program. The integrator hung a Siemens 6ES5185-3UA13 off the S5-155U via a 6ES5 727 EU cable: 21 fresh slots, 5 V/18 A backplane power (shared load with the central PS935 — the EG 185U’s PSU feeds only its own 21-slot backplane, not the central rack), integrated fan pulling 18.75 kg of steel-and-copper behind the existing cabinet cutout. Five years later, the Siemens 6ES5185-3UA13‘s fan started audibly bearing-growling during summer peaks (cabinet ambient 52°C), and the 5 V test-socket green LED flickered — a prelude to backplane ripple that would eventually have tripped the CP443’s EU heartbeat. The plant swapped the whole Siemens 6ES5185-3UA13 during a 4-hour kiln-hold (the unit is heavy and the EU cable needs careful reseating), and the 5 V ripple returned to <30 mV. For any S5-135U/155U plant — power-gen turbine aux, cement kiln, steel-rolling, large batch-pharma — where the 18-slot central rack is maxed and the “add one more FM” conversation has come up, the Siemens 6ES5185-3UA13 is the reason you don’t have to migrate the whole bay yet.
Parameter:
| Main Parameters | Value/Description |
|---|---|
| Product Model | Siemens 6ES5185-3UA13 |
| Manufacturer | Siemens AG (SIMATIC S5-135U/155U family) |
| Product Category | EG 185U Expansion Unit with Integrated Power Supply |
| Input Voltage | 120 / 230 V AC (selectable, 1-phase) |
| Output 5 V (backplane) | 5 V DC, 18 A (feeds the 21-slot EU backplane for S5 modules) |
| Output 15 V | 15 V DC, 0.5 A (aux, e.g. selected analog SM referencing) |
| Output 24 V | 24 V DC, 1 A (aux, +25%/–20% tolerance, test-socket green LED) |
| Number of Slots | 21 (S5-100U/300U/400U modules mount here via EU expansion bus) |
| Cooling | Integrated fan submodule (230 V AC variant, 6ES5 988-3LA11 class) |
| Backup Battery | None — battery resides on central S5-135U/155U rack (PS935 area) |
| Mounting | S5 expansion rail / 19″ cabinet bay |
| Dimensions (W×H×D) | ~450 × 265 × 280 mm (21-slot S5 euro-format, fan protrusion included) |
| Weight | ~18.75 kg (heavy — steel chassis + PSU + fan + copper) |
| Operating Temperature | 0 °C to +60 °C (fan-assisted; de-rate if ambient >50°C) |
| Ingress Protection | IP20 (control cabinet) |
| Certifications | CE, UL 508, CSA C22.2 No.142 |
| Commodity / ECCN | 85369095 |
Technical Principles and Innovative Values:
- Innovation Point 1: One-box expansion: 21 slots + PSU + fan, no separate S5-100U rack + PS935 + fan submodule to source. The Siemens 6ES5185-3UA13 collapses what would be three S5 line-items (empty 21-slot rack + PS935 5 V/18 A + fan submodule) into a single EG 185U BOM line. For S5-135U/155U plants adding a satellite I/O/CP/FM cluster 3–15 m away from the central rack (EU cable max ~3 m for 5 V backplane integrity, longer runs need repeater), this is the cleanest grow-path — one unit, one power feed, one fan speed, one set of test-socket LEDs.
- Innovation Point 2: 5 V/18 A backplane with test-socket green LED on 24 V/15 V aux. The Siemens 6ES5185-3UA13 brings out “V o/p2 — 24 V/15 V o.k.” as a green LED + test sockets on the front fascia, so a maintenance tech can DMM-probe the 5 V/15 V/24 V rails without pulling the unit — a small but critical detail when diagnosing “why did the FM355 on Slot 19 just throw a watchdog” 25 years into service.
- Innovation Point 3: Battery-less by design — backup lives upstream. Because the Siemens 6ES5185-3UA13 is an expansion, not a central rack, it deliberately carries no lithium backup battery (that lives on the S5-135U/155U’s PS935 + 6ES5 370 battery cassette). This avoids the “two batteries, one dead, which one is holding the CPU RAM” confusion that plagues mixed-age S5 bays. Power loss on the EG 185U just kills its own 21 slots — the central CPU RAM stays alive on the central rack’s battery.
- Innovation Point 4: Fan-integrated in the same 21-slot footprint. A 5 V/18 A linear PSU + 21 S5 modules (especially if some are FM/CP class draw) generates real heat — the Siemens 6ES5185-3UA13 bakes the fan submodule (230 V AC, 6ES5 988-3LA11 equivalent) into the unit rather than making it a separately-ordered submodule. At 18.75 kg, most of that mass is heatsink + transformer + fan shroud — this thing is built for 1990s-vintage cabinet ambient (sometimes 55°C) without complaint.
