Siemens 6ES7317-2FK14-0AB0 Retrofit-Compatible CPU for S7-300

Siemens 6ES7317-2FK14-0AB0 Retrofit-Compatible CPU for Legacy S7-300 Systems

The Siemens 6ES7317-2FK14-0AB0 is a high-performance CPU module from the SIMATIC S7-300 series, designed to serve as a direct retrofit-compatible replacement for aging or discontinued CPU units in legacy automation systems. As industrial facilities face increasing pressure to extend the operational life of existing control infrastructure while maintaining production continuity, the 6ES7317-2FK14-0AB0 offers a proven migration path that minimizes engineering risk, reduces downtime, and preserves existing program logic and field wiring investments.

This CPU module — part of the CPU 317F-2 DP/PN family — integrates dual communication interfaces supporting both PROFIBUS DP and PROFINET IO, making it uniquely suited for facilities transitioning from legacy fieldbus architectures to modern Ethernet-based control networks without requiring a full system overhaul. Whether you are replacing a failed CPU 315-2 DP, upgrading from a CPU 316-2 DP, or migrating an entire S7-300 rack to a more capable processor, the 6ES7317-2FK14-0AB0 provides the processing power, memory capacity, and communication flexibility required for demanding retrofit projects.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

A successful retrofit using the 6ES7317-2FK14-0AB0 begins well before the physical swap. Engineers must conduct a thorough pre-migration audit covering power budget, slot allocation, communication topology, and program compatibility. The following planning steps are critical to a smooth transition.

Power Supply Verification: The existing Siemens PS 307 5A (6ES7307-1EA01-0AA0) or PS 307 10A (6ES7307-1KA02-0AA0) power supply must be verified against the total current draw of the new CPU plus all installed I/O modules. The CPU 317F-2 DP/PN draws approximately 800 mA from the 5 VDC backplane bus. If the existing power supply is marginal, upgrading to a higher-capacity unit before the CPU swap prevents instability during commissioning.

Rack and Slot Configuration: The 6ES7317-2FK14-0AB0 occupies slot 2 on any standard S7-300 mounting rail. Existing SM 321 digital input modules, SM 322 digital output modules, SM 331 analog input modules, and SM 332 analog output modules remain fully compatible and do not require replacement. The CPU automatically recognizes the installed I/O configuration during startup, provided the hardware configuration in STEP 7 or TIA Portal is updated to reflect the new CPU type.

Communication Module Retention: If the existing system uses a CP 343-1 Lean (6GK7343-1CX10-0XE0) for Ethernet connectivity or a CP 342-5 (6GK7342-5DA03-0XE0) for PROFIBUS master functionality, these communication processors remain fully compatible with the 317F-2 DP/PN and can be retained in their existing rack positions. This eliminates the need to reconfigure network topology or re-address field devices.

Memory Card Migration: Program backup and transfer is performed via the SIMATIC Micro Memory Card (MMC). Before decommissioning the old CPU, the existing program should be uploaded to STEP 7 and archived. The new 6ES7317-2FK14-0AB0 ships without a pre-loaded program; a compatible MMC such as the 6ES7953-8LJ31-0AA0 (8 MB) should be prepared with the migrated and validated program before installation.

HMI and SCADA Compatibility: Existing Siemens TP700 Comfort or MP377 HMI panels connected via MPI or PROFIBUS DP will continue to communicate with the new CPU without driver changes, as the 317F-2 DP/PN maintains full MPI compatibility. For panels connected via PROFINET, the CPU’s integrated PN interface eliminates the need for a separate IE/PB Link PN IO gateway module, simplifying the cabinet layout.

Signal Isolation and Wiring Integrity: In environments with high electromagnetic interference — common in steel mills, chemical plants, and heavy manufacturing — it is advisable to inspect and, where necessary, replace aging signal isolators and surge protection modules on analog I/O channels during the CPU retrofit. This prevents signal drift and false triggering that can occur when a more sensitive CPU is installed in a previously marginal wiring environment.

Downtime Control During System Migration

Minimizing production interruption is the primary concern for any retrofit project involving a running S7-300 system. The following strategy has been validated across multiple industrial retrofit deployments and is recommended for facilities using the 6ES7317-2FK14-0AB0 as a replacement CPU.

Pre-Shutdown Preparation: Complete all hardware configuration changes, program compilation, and simulation testing in STEP 7 or TIA Portal before the scheduled maintenance window. Use the PLCSIM simulation environment to validate the migrated program against the original I/O list. Prepare the new CPU with the MMC pre-loaded and verified. Stage all replacement components — including the CPU module, MMC, and any updated terminal blocks — at the installation site before shutdown.

Controlled Shutdown Sequence: Place the existing CPU in STOP mode via the mode selector switch or through the programming interface. Document the current output states and any active interlocks. Power down the rack using the PS 307 power supply switch rather than disconnecting field wiring, preserving terminal block integrity and reducing reconnection errors.

Physical Replacement: Remove the existing CPU from slot 2. The 6ES7317-2FK14-0AB0 installs directly into the same slot using the standard S7-300 bus connector. No additional mounting hardware or rail modification is required. Insert the pre-loaded MMC before powering up.

Commissioning and Validation: After power-up, the CPU performs a self-test and loads the program from the MMC. Verify the hardware configuration download is accepted without module mismatch errors. Perform a controlled RUN mode test with outputs inhibited where possible, confirming all I/O addresses, analog scaling, and communication links are functioning correctly before releasing the system to production.

Program Logic Preservation: The original ladder logic, function block diagrams, and structured text programs developed in STEP 7 are fully compatible with the 317F-2 DP/PN without modification in most retrofit scenarios. Where the original CPU lacked failsafe capability, the F-CPU features of the 6ES7317-2FK14-0AB0 can be activated progressively, allowing safety functions to be integrated into the existing program structure during future planned maintenance windows rather than requiring immediate full-system reconfiguration.

Retrofit Support FAQ

Q1: Is the 6ES7317-2FK14-0AB0 a direct drop-in replacement for the CPU 315-2 DP or CPU 316-2 DP?
A: In most cases, yes. The 317F-2 DP/PN uses the same S7-300 rack slot, backplane bus connector, and STEP 7 programming environment. The primary differences are increased working memory, dual DP/PN communication, and failsafe capability. The existing hardware configuration must be updated in STEP 7 to reflect the new CPU type, but field wiring, I/O modules, and communication processors typically require no changes.

Q2: What testing is performed before shipment?
A: Every 6ES7317-2FK14-0AB0 unit supplied by NINERMAS undergoes functional power-on testing and communication interface verification before dispatch. Units are inspected for physical integrity, firmware version, and operational status. A 12-month warranty is provided from the date of shipment, covering manufacturing defects and functional failures under normal operating conditions.

Q3: Can the existing PROFIBUS DP network be retained when installing this CPU?
A: Yes. The integrated PROFIBUS DP interface on the 6ES7317-2FK14-0AB0 supports both master and slave operation and is fully compatible with existing DP field devices, distributed I/O stations such as the ET 200M or ET 200S, and third-party PROFIBUS devices. The DP network address and baud rate settings are configured in STEP 7 and transferred via the MMC, requiring no changes to field device addressing.

Q4: What is the long-term supply availability for this module?
A: NINERMAS maintains dedicated inventory of the 6ES7317-2FK14-0AB0 and related S7-300 components to support long-term retrofit and maintenance requirements. As Siemens has announced the phase-out of the S7-300 product line, securing verified replacement stock from a reliable distributor is essential for facilities that cannot yet migrate to S7-1500 or TIA Portal-based platforms. We provide ongoing supply support with consistent lead times and guaranteed 12-month warranty coverage on all units.