At a Glance. The CPU 1511-1 PN (6ES7511-1AK02-0AB0) and CPU 1513-1 PN (6ES7513-1AL02-0AB0) are the two entry points of the SIMATIC S7-1500 family, and both program in the same TIA Portal environment with identical instruction sets and bit execution time (30 ns). The decision is therefore purely a resource question: the 1511 carries 150 KB program / 1 MB data memory and 1024 I/O, while the 1513 doubles the program memory to 300 KB, adds 1.5 MB data, 2048 I/O and motion control for up to 4 axes. Pick the 1511 for compact machines and single-panel OEM equipment; pick the 1513 when the program is growing, the I/O count crosses ~1000 points, or coordinated motion enters the picture.
1. Head-to-Head Specification Table
| Specification | CPU 1511-1 PN | CPU 1513-1 PN |
|---|---|---|
| Order number | 6ES7511-1AK02-0AB0 | 6ES7513-1AL02-0AB0 |
| Program memory | 150 KB | 300 KB |
| Data memory | 1 MB | 1.5 MB |
| Bit execution time | 30 ns | 30 ns |
| PROFINET interface | 1 (2-port switch) | 1 (2-port switch) |
| Max I/O | 1024 | 2048 |
| Motion control | Basic | Up to 4 axes |
| Programming | TIA Portal V15+ | TIA Portal |
| Certifications | CE, UL, cUL, FM, ATEX | CE, UL |
Note that raw speed is identical — 30 ns per bit operation on both CPUs. The 1513 buys you memory headroom, I/O headroom and multi-axis motion, not faster logic.
2. When the CPU 1511 Is Enough
The 1511-1 PN comfortably handles machines in the 100-500 I/O range: packaging sub-assemblies, single-line conveyors, pump skids, small water treatment panels and machine retrofits where the logic is sequential and motion is simple. Because both CPUs share the same TIA Portal instruction set, a project started on a 1511 migrates to larger CPUs without code rewrites — making the 1511 a safe, low-cost entry point with an upgrade path.
3. When to Step Up to the CPU 1513
Choose the 1513-1 PN when any of the following apply:
- I/O above roughly 1000 points — the 1024-point ceiling of the 1511 becomes a hard wall;
- Coordinated motion up to 4 axes — positioning, gearing or camming on servo drives;
- Large data sets — recipes, logging buffers or HMI archiving that stress the 1 MB data memory;
- Program growth risk — OEM platforms where customer options will keep expanding the code base.
4. A Proven System Pairing
Around either CPU, a typical mid-range SIMATIC automation stack looks like this:
- Drive: the SINAMICS G120C (6SL3210-5BE27-5UV0), a compact 7.5 kW 400 V inverter with built-in Class A EMC filter and Safe Torque Off (STO, SIL 3), talking PROFINET straight to the CPU;
- HMI: the KTP700 Comfort (6AV2124-0GC01-0AX0), a 7-inch 800x480 touch panel with 8 function keys, configured in the same TIA Portal project;
- Network: an SCALANCE XC208 (6GK5208-0BA10-2AA2) 8-port managed switch (PROFINET Conformance Class B, −40 °C to +70 °C) segments the PROFINET and office traffic;
- Soft starting: the SIRIUS 3RW5513 (3RW5513-1HA14), 15 kW at 400 V with integrated bypass and PROFINET communication, for pumps, fans and conveyors that must not hammer the mains.
All six order numbers above are in stock at Glorient and ship internationally with documentation.
5. Legacy Replacement: Migrating from S7-300 / S7-400
A large share of 1511/1513 demand comes from obsolescence-driven migration. Key points:
- One-way code port: S7-300 logic ports into TIA Portal with block-level rework; the 1513’s doubled memory absorbs the typical growth when step conversion inflates code size.
- PROFINET replaces PROFIBUS-DP: legacy CP cards and DP slaves map onto the CPU’s integrated 2-port PROFINET switch plus a SCALANCE switch layer.
- Panel consolidation: an MP277/OP-era HMI replaces cleanly with the KTP700 in the same project tree.
Send Glorient your existing S7-300/400 order numbers and rack layout; we will return a 1511-or-1513 migration bill of materials, including drive and HMI counterparts, within one business day.
6. FAQ
Can a CPU 1511 run a program written for a CPU 1513?
Almost always yes — both share the TIA Portal instruction set — provided the program stays within 150 KB code, 1 MB data and 1024 I/O. Motion beyond basic control requires the 1513.
What is the difference between 6ES7511-1AK02-0AB0 and 6ES7513-1AL02-0AB0?
The order numbers denote the two CPUs themselves: 1511-1 PN with 150 KB/1 MB/1024 I/O and the 1513-1 PN with 300 KB/1.5 MB/2048 I/O and up to 4 motion axes. Bit execution speed (30 ns) is identical.
Do both CPUs connect to a G120C drive and KTP700 panel?
Yes. The G120C, KTP700 and SCALANCE switches all communicate over PROFINET, so either CPU drives the same stack — the CPU choice does not change the peripheral selection.
Need a quote? Browse in-stock Siemens automation components — CPUs, SINAMICS drives, SIRIUS control gear, HMI panels and SCALANCE networking — or send your I/O list for a same-week system quotation.