Siemens SIMATIC S7-300 CPU 315-2 DP

What the CPU 315-2 DP does

The CPU executes the S7-300 control program, manages the local rack, and coordinates configured communications and distributed I/O. Siemens documentation identifies CPU 315-2 DP versions within the standard S7-300 CPU family and describes a second interface for DP master/slave use on applicable revisions. In a drilling or industrial cabinet, the CPU may coordinate drives, remote I/O, operator interfaces, permissives, alarms, and equipment sequences.

The short model name is not a complete purchasing identity. Siemens published multiple CPU 315-2 DP order numbers over the life of the platform, with differences in memory, hardware, firmware, and engineering requirements. A label reading “315-2 DP” establishes the family but not necessarily an interchangeable spare. The installed STEP 7 hardware configuration and the exact order number remain controlling.

The complete Siemens order number matters

Record the full Siemens MLFB, normally beginning with 6ES7, exactly as printed. Keep every letter, digit, dash, and suffix. Also record the hardware release, firmware version, serial information, and the Micro Memory Card identification where applicable. A partial search such as Siemens 315 2DP can return several generations that look alike but are not automatically equivalent.

• Complete CPU order number and product designation.
• Hardware release and firmware version from the label or diagnostics.
• Memory card part number and a controlled backup of the program.
• Rack, power supply, signal modules, communications modules, and occupied slots.
• PROFIBUS network role, address, baud rate, and connected DP stations.
• STEP 7 project version, hardware catalog entry, and available source/comments.
• Current fault LEDs, diagnostic buffer information, and the event that started the inquiry.

Replacement, obsolescence, and migration planning

Siemens lifecycle information is order-number specific. Some CPU 315-2 DP products are listed as discontinued or spare parts, while later S7-300 variants have different phase-out histories. That is why ETSCO will not assign one lifecycle statement or one successor to every unit found through the short query CPU 315-2 DP obsolete.

An exact-spare request and a controls migration are different jobs. An exact spare still requires confirmation of firmware, memory card, project backup, and network configuration. A migration may affect the hardware catalog, program behavior, timing, communications, connectors, cabinet layout, and commissioning procedure. Even a Siemens-published successor or spare relationship should be checked against the actual application before the original CPU is removed.

Preserve a verified upload and the existing memory card before work. Do not assume that a program can be recovered from a failed or password-protected CPU. Where production risk is material, the owner should plan a bench test, rollback path, and controlled commissioning window.

What to send ETSCO

Send a straight-on photograph of the CPU label, the front with covers open, the memory card, the full rack, and the PROFIBUS connectors. Transcribe the complete order number in the message so it can be searched without relying on image quality. Include the STEP 7 project archive if the owner is authorized to share it, or state clearly that the project is unavailable.

Describe whether the CPU is running, faulted, physically damaged, or removed from service. Include the requested outcome: identical spare, contingency spare, bench evaluation, or migration planning. ETSCO can then separate identification from engineering work and confirm what support is currently possible. No stock, price, compatibility, or lead-time assumption is made from the family name.

Where it fits in legacy cabinet support

A CPU problem often involves more than the processor. ETSCO can review the surrounding PLC/server cabinet, remote-I/O path, control power, connectors, drive interfaces, and documentation package. The Allen-Bradley 1747-SN page addresses a comparable legacy remote-I/O concern, while the ABB FEN-31 page covers drive feedback hardware.

See ETSCO's Oil & Gas and Industrial pages for cabinet and system context. For an exact requirement, review OEM Parts, email sales@etsco.net, or use the Request a parts quote.

Frequently Asked Questions