Siemens 6ES7515-2FM02-0AB0 is a SIMATIC S7-1500F (fail-safe) central processing unit designed for mid-range motion, process, and safety-related automation where deterministic Ethernet networking and integrated diagnostics matter. In practical terms, it’s the kind of CPU you choose when you want one controller to run your standard machine logic and your safety logic side-by-side, while still keeping cycle times tight and troubleshooting sane.
This model is identified in its data sheet as CPU 1515F-2 PN and (in many catalogs) is marked as a spare part. It includes 750 KB work memory for program and 3 MB work memory for data, and it requires a SIMATIC Memory Card for load memory and operation.
What makes this CPU “feel fast” in real machines
Automation performance is rarely about one headline number; it’s about how quickly the CPU can chew through logic, how predictably it can exchange I/O, and how confidently you can scale the system without turning it into a spaghetti monster.
On the CPU side, Siemens specifies typical processing times such as 30 ns for bit operations, 36 ns for word operations, 48 ns for fixed-point arithmetic, and 192 ns for floating-point arithmetic.These figures are useful because they translate directly into how much logic you can execute per cycle when your program contains a lot of comparisons, interlocks, counters, and numeric calculations.
On the network side, the CPU provides two PROFINET interfaces. The first interface is PROFINET IRT with a 2-port switch, and the second interface is PROFINET RT. This dual-interface approach is a big deal in the field: it lets you segment traffic (for example, keep time-critical drives and remote I/O on one side, and SCADA/MES/engineering access on the other) without immediately resorting to extra switches and “why is the line down” meetings.
Key specifications at a glance
| Item | Specification |
|---|---|
| Order number | 6ES7515-2FM02-0AB0 |
| Product type designation | CPU 1515F-2 PN |
| Work memory | 750 KB program, 3 MB data |
| Load memory | SIMATIC Memory Card, up to 32 GB (max.) |
| Supply voltage | 24 V DC (19.2…28.8 V permissible) |
| Current consumption | 0.8 A rated (max. 1.1 A) |
| Integrated display / keys | 6.1 cm display, 8 keys, 2 mode buttons |
| PROFINET interfaces | 2 interfaces; X1 has 2 ports with integrated switch; X2 has 1 port |
| Physical dimensions (listed by distributor) | 70 × 129 × 147 mm |
Deterministic PROFINET behavior (IRT/RT) for modern plants
If your automation network is “best effort,” you eventually discover the hard way that physics plus Ethernet jitter can ruin your day. This CPU supports PROFINET IO Controller and PROFINET IO Device roles, includes a web server, and supports media redundancy using MRP (IEC 62439-2).
For applications that require more deterministic exchange, Siemens lists isochronous capabilities. The CPU supports isochronous mode (distributed and central), and it provides typical update-time ranges for PROFINET IRT and RT based on send cycles. In plain language: you can build networks where motion-related devices get predictable time slots, while less critical devices ride along without disrupting the schedule.
PROFINET features table
| Networking / diagnostics feature | Notes |
|---|---|
| PROFINET IO Controller | Supported |
| PROFINET IO Device | Supported |
| IRT capability | Supported on the PROFINET interface |
| Web server | Supported (useful for quick diagnostics) |
| Open IE communication | Supported; can be encrypted (optionally) |
| Media redundancy | MRP Automanager per IEC 62439-2 |
| Time synchronization | NTP supported |
Capacity and scalability (the “how big can I build this?” question)
The 1515F-2 PN is positioned as a mid-range CPU with practical scaling headroom. Siemens specifies support for up to 8,192 I/O modules, with 32 KB inputs and 32 KB outputs in the I/O address area, and up to 64 distributed I/O systems (architecturally defined in the S7-1500 ecosystem).
This CPU also supports substantial program structuring: Siemens lists a total of 8,000 block elements (OB/FB/FC/DB/UDT combined) and large maximum block sizes (up to 500 KB for OB/FB/FC). That matters when you’re building modular codebases with reusable function blocks, safety blocks, diagnostics blocks, and comms blocks without running into artificial ceilings too early.
Memory and program structure table
| Resource | Specification |
|---|---|
| Work memory (program/data) | 750 KB / 3 MB |
| Load memory | Memory Card required; up to 32 GB |
| Retentive data (standard) | Up to 512 KB (incl. timers/counters/flags etc.) |
| Number of timers/counters | 2,048 S7 timers; 2,048 S7 counters (IEC versions limited by memory) |
| Block element capacity | 8,000 total (OB/FB/FC/DB/UDT) |
Safety integration: why the “F” matters
The “F” in S7-1500F indicates a fail-safe CPU intended for safety-related automation architectures. In a typical Siemens distributed safety setup, fail-safe digital input modules capture safety sensor states and send safety frames to the F-CPU, while fail-safe digital output modules drive safety actuators (for example, contactors or STO-capable drive interfaces).
A very common pattern is emergency stop (E-Stop) functionality implemented using PROFINET with the PROFIsafe profile, where a fail-safe S7 CPU acts as IO controller and distributed fail-safe I/O sits on the network. Siemens application documentation describes this approach explicitly for achieving high safety levels (e.g., SIL 3 / PL e) in appropriate designs.
Typical safety architecture (conceptual)
| Layer | Typical elements |
|---|---|
| Safety CPU layer | S7-1500F CPU executing safety and standard programs |
| Safety I/O layer | Fail-safe DI/DO modules exchanging safety frames with the F-CPU |
| Network layer | PROFINET plus PROFIsafe for safety messaging (system design dependent) |
| Actuation layer | Contactors, safety relays, safe drive functions, or other certified safety actuators |
Engineering, commissioning, and maintenance realities
From an engineering workflow standpoint, Siemens notes that this CPU is configurable/integrated in STEP 7 (TIA Portal) from V17 (with FW V2.9) or V16 (with FW V2.8) and higher. It also supports I&M data (I&M0 to I&M3), which helps with asset management, replacement logistics, and traceability in regulated environments.
Operationally, the CPU includes a front display (6.1 cm) and physical keys, which is underrated until you’ve had to diagnose a cabinet in a noisy plant with a laptop battery dying at the worst possible moment.
Practical buying/installation checklist (to avoid the classic “we forgot the one thing”)
| Item to plan | Why it matters |
|---|---|
| SIMATIC Memory Card | The CPU requires it; also provides load memory up to 32 GB |
| 24 V DC power design | CPU rated 24 V DC; ensure supply margins and cabinet wiring are correct |
| PROFINET topology | Use dual interfaces intentionally (segmentation, IRT devices, redundancy strategy) |
| Safety system concept | Choose fail-safe I/O and PROFIsafe architecture appropriate to the required safety level |
| TIA Portal version alignment | Match project toolchain to firmware expectations (V16/V17+) |
Closing note
Siemens 6ES7515-2FM02-0AB0 is best viewed as a “balanced” fail-safe CPU: fast enough for demanding cyclic logic, built for deterministic PROFINET networks, and designed to integrate functional safety into the same controller platform rather than bolting it on as an afterthought. If your machine or line is heading toward more networked drives, more distributed I/O, and stricter safety requirements, this CPU sits in a sweet spot where performance, diagnostics, and safety architecture can scale together instead of fighting each other.
