At a Glance. Two CPUs in the SIMATIC S7-1500 family account for a large share of our quotations: 6ES7511-1AK02-0AB0, the CPU 1511-1 PN, and 6ES7513-1AL02-0AB0, the CPU 1513-1 PN. They share the same form factor, the same PROFINET port arrangement and the same engineering environment, so the decision comes down to memory, execution speed and motion capability — each of which has a straightforward test. Both are supplied through our Siemens stock, alongside peripherals such as the KTP700 Comfort HMI panel.
1. The comparison that matters
| Characteristic | CPU 1511-1 PN | CPU 1513-1 PN |
|---|---|---|
| Position in the family | Entry level | Mid range |
| Program memory | 150 KB | 300 KB |
| Data memory | 1 MB | 1.5 MB |
| Bit execution time | 30 ns | Faster |
| Integrated interface | PROFINET | PROFINET |
| Motion control | Basic | Enhanced |
Because both CPUs carry an integrated PROFINET interface, the network architecture is not a differentiator: either can act as the controller for remote I/O, drives and HMI panels on the same segment.
2. Three tests that decide it
Test 1 — Program size
Export the project and look at the actual memory consumption rather than the estimated lines of code. Library blocks, safety programs and communication blocks consume considerably more than the logic they appear to contain. If the existing program already sits above roughly half of the 150 KB available on the 1511-1 PN, plan on the 1513-1 PN, or above it again for larger machines.
Test 2 — Data volume and recipe handling
Data memory is what limits recipe storage, data logging and large arrays of process values. Machines that keep production records or handle many parameter sets exhaust data memory long before they exhaust program memory. The higher figure on the 1513-1 PN is often the real reason a project moves up a size.
Test 3 — Motion
If the machine needs coordinated motion, camming or interpolated axes, the enhanced motion capability of the 1513-1 PN is the deciding feature. For simple positioning with drives that handle their own motion internally, the 1511-1 PN is normally sufficient.
3. Peripherals that pair with either CPU
Both CPUs work with the same accessory families, which simplifies spares:
- HMI: SIMATIC HMI KTP700 Comfort, a 7-inch widescreen panel with PROFINET, 800 × 480 resolution and combined touch and key operation.
- Remote I/O: ET 200SP and ET 200MP stations on PROFINET.
- Motor starting: SIRIUS soft starters such as 3RW5513-1HA14, which reduce starting current on pumps, fans and conveyors without the mechanical shock of direct-on-line starting.
- Programming: TIA Portal, with the project version matched to the firmware in the CPU.
4. Practical notes for ordering
- Check the firmware. A CPU ordered with older firmware may need updating before it will open a project created in a newer TIA Portal version. State the required firmware when ordering if the project is fixed.
- Memory cards are separate. The S7-1500 uses a SIMATIC memory card as its program and data medium. It is not included and is not interchangeable with generic SD cards.
- Buy the spare the same way. For critical machines a spare CPU should carry the same article number and the same memory card image, so that a swap is a hardware task rather than an engineering task.
- Cross-generational projects. Where a machine was originally built around S7-300 or S7-400 hardware, the migration to S7-1500 involves more than a CPU substitution. Send the existing IO list and we can help map the configuration.
Browse the automation technology category or the Siemens brand page for current availability. If you need a quotation for a complete controller package — CPU, memory card, HMI and I/O — send the machine specification and we will assemble it as a single referenced list.