A control cabinet can be full of premium PLCs, motion drives, and Ethernet hardware, yet still behave like a haunted radio if the 24 V DC rail is unstable. Random CPU resets, intermittent I/O faults, nuisance safety trips, and communication dropouts often trace back to power that technically meets the label but fails during inrush, load steps, or brief mains dips. The Siemens 6EP1336-2BA10, part of the SITOP PSU100S family, is built specifically to make industrial 24 V power boring again: stable regulation, cabinet-ready diagnostics, and protection behavior designed for real automation loads.
This model provides a regulated and isolated 24 V DC output with a rated current of 20 A (up to 480 W), targeting applications such as PLC and remote I/O power distribution, industrial networking devices, HMIs, sensors, and actuator circuits that demand predictable DC under changing conditions.
What makes 6EP1336-2BA10 practical in the field
Automatic 120/230 V AC range selection (single-phase).
The input is specified for a 1-phase AC network with automatic range selection and two defined operating ranges: 85–132 V AC and 176–264 V AC, with nominal 120/230 V operation. This is useful for global equipment designs that may ship into different facilities without swapping power supplies.
Hold-up time to ride through short power interruptions.
Siemens specifies a minimum buffering time of 20 ms at rated load during a brief power failure (at Vin = 120/230 V). In practice, this can help prevent controller reboots during short dips that are common when large loads switch on the same feeder.
Adjustable output voltage for long cable runs.
The output is adjustable via potentiometer, allowing 24–28 V DC (with max. 480 W). That adjustment range can compensate for voltage drop across long distribution wiring, diode modules, or high-current terminal blocks—without needing a separate booster supply.
Built-in status and alarm signaling.
Besides a green “24 V OK” LED, the unit includes a relay contact (NO) rated 50 V DC / 0.3 A for “24 V OK” signaling—handy for SCADA alarms, PLC diagnostics, or maintenance panels.
Overload and short-circuit behavior engineered for automation loads.
The rated output current is 20 A, and Siemens lists an overload capability of 150% of rated current up to 5 s/min in normal operation. For short-circuit events, the datasheet specifies a typical 35 A short-circuit current (both at start-up and during operation) with 100 ms duration, and electronic shutdown with automatic restart.
Technical Specifications Table (Key Data)
| Category | Specification (Siemens 6EP1336-2BA10) |
|---|---|
| Product family | SITOP PSU100S |
| Input supply | 1-phase AC, automatic range selection |
| Rated input voltage | 120 V / 230 V AC |
| Input voltage range | 85–132 V AC and 176–264 V AC |
| Line frequency | 47–63 Hz (50/60 Hz nominal) |
| Input current (rated) | 7.5 A at 120 V; 3.5 A at 230 V |
| Inrush current limiting | 11 A max at 25 °C; I²t 10 A²·s max |
| Buffering / hold-up time | 20 ms minimum at rated load |
| Output type | Controlled, isolated DC voltage |
| Rated output | 24 V DC / 20 A |
| Output adjustment | 24–28 V via potentiometer; max 480 W |
| Voltage tolerance | 3% overall tolerance |
| Ripple / peak | Ripple 150 mV max; peak 240 mV max |
| Efficiency | 90% |
| Power loss (typ.) | 53 W at rated output |
| Overload / protection | 150% Iout rated up to 5 s/min; electronic shutdown, auto restart |
| Short-circuit (typ.) | 35 A for 100 ms (startup/operation) |
| IP rating | IP20 |
| Status / signaling | Green LED “24 V OK”; relay NO contact 50 V DC / 0.3 A |
| Operating temperature | 0–70 °C (natural convection) |
| Terminals | Screw terminals; output has two + and two − terminals |
| Dimensions (W×H×D) | 115 × 145 × 150 mm |
| Net weight | 2.5 kg |
| Mounting | Snap-on DIN rail EN 60715 |
| Recommended clearances | Top 50 mm, bottom 50 mm, sides 0 mm |
| Approvals (examples) | CE, UL/cULus Listed (UL 508 / CSA), UKCA, EAC |
| Reliability indicator | MTBF at 40 °C: 1,778,916 h |
Installation guidance that prevents “mystery failures”
Mounting orientation and airflow are not optional details.
The operating instructions recommend DIN rail mounting with at least 50 mm clearance above and below the unit, supporting natural convection cooling. The same document also describes mounting with terminals positioned at the bottom and warns to follow the documented safety notes during installation and commissioning.
Feeder protection should match real-world cabinet behavior.
The datasheet references recommended feeder protection such as a 10 A miniature circuit breaker with characteristic C (and also cites specific Siemens breaker options depending on 120 V vs 230 V operation). This matters because undersized or overly sensitive protection can cause nuisance trips during inrush or heavy load transients.
Use voltage adjustment for engineering reasons, not vibes.
The output adjustability (24–28 V) is a powerful tool when distributing 20 A across a cabinet. Adjusting slightly upward can compensate for cable drop at the load end, but it should be done with downstream device limits in mind—especially if you power mixed loads like PLC electronics, sensors, and relays from the same rail. The official instructions also caution that voltage setting should be performed only for first installation and not in potentially explosive atmospheres.
Where 6EP1336-2BA10 fits best
This power supply is a strong match when you need a robust 24 V DC backbone for:
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PLC, remote I/O, and fieldbus couplers that must not brown out during load steps
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HMI panels and industrial Ethernet switches that are sensitive to undervoltage resets
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Mixed sensor/actuator systems where ripple and transient response affect signal quality
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Control cabinets that benefit from alarm contacts and simple “24 V OK” diagnostics
Because the unit includes a “24 V OK” relay contact and defined overload/short-circuit behavior, it also supports maintainability: you can wire health signals into a PLC input, log events, and reduce the mean time to diagnose intermittent power issues.
Summary
Siemens 6EP1336-2BA10 (SITOP PSU100S) is a cabinet-grade 24 V / 20 A DIN-rail power supply built for industrial automation stability: single-phase input with automatic 120/230 V range selection, regulated and isolated output with 24–28 V adjustment, 20 ms minimum hold-up time, clear “24 V OK” indication plus relay signaling, and protection behavior designed to survive overloads and shorts without turning your control system into a reboot festival.
