Siemens 6ES7952-1AS00-0AA0 S7-400 RAM Memory Spare Part

Overview

Siemens 6ES7952-1AS00-0AA0 S7-400 RAM Memory Spare Part: Maintenance-Proven for Factory Uptime

The Siemens 6ES7952-1AS00-0AA0 is a 16MB RAM Memory Card designed for the SIMATIC S7-400 programmable logic controller platform — one of the most widely deployed high-availability PLC systems in process automation, discrete manufacturing, and critical infrastructure. As a plug-in memory module, it stores the user program, data blocks, and system configuration directly on the CPU rack, enabling fast program reload after a CPU swap, battery failure, or firmware recovery event.

For maintenance engineers managing aging S7-400 installations, keeping a verified spare of the 6ES7952-1AS00-0AA0 on the shelf is a fundamental risk-reduction measure. Program loss due to a failed or corrupted memory card can extend unplanned downtime from minutes to hours — particularly when the backup program must be reloaded from an engineering workstation via STEP 7 or TIA Portal. A pre-tested, ready-to-install memory card eliminates that dependency and restores the line faster.

Procurement engineers sourcing long-term supply for S7-400 platforms should note that Siemens has announced end-of-production timelines for several S7-400 components. Establishing a multi-unit stock of the 6ES7952-1AS00-0AA0 now — alongside compatible CPU modules and power supply spares — is a proven strategy for extending system life without a full migration project.

Every unit supplied by KNMKS is sourced from verified industrial channels, subject to pre-shipment functional inspection, and covered by a support terms confirmed by quotation against defects in materials and workmanship.

Spare Maintenance Table

Maintenance Planning for Continuous Operation

When replacing the 6ES7952-1AS00-0AA0 during a scheduled or emergency maintenance event, a thorough inspection of the surrounding S7-400 system components is strongly recommended to prevent repeat failures and confirm system integrity before restart.

CPU and Backplane: Inspect the S7-400 CPU module (such as the CPU 414-3 or CPU 416-3) for firmware version compatibility with the replacement memory card. Check the backplane bus connectors and rack for oxidation or mechanical damage. A faulty backplane can cause intermittent memory card read errors that are difficult to diagnose without component-level isolation.

Power Supply Module: The S7-400 PS 407 or PS 405 power supply module should be verified for stable 24 VDC and 5 VDC rail output. Voltage fluctuations on the backplane supply are a known cause of memory card corruption and CPU faults. If the power supply is more than five years old or shows output ripple, include it in the replacement plan alongside the memory card.

Battery and Capacitor Backup: The S7-400 CPU relies on a backup battery or internal capacitor to retain RAM contents during power loss. If the battery (such as the 6ES7971-1BA00-0AA0 lithium battery) is at or near end of life, a power interruption will result in program loss even with a healthy memory card installed. Replace the battery as part of the same maintenance window.

I/O Modules and Signal Wiring: During the cabinet inspection, verify the status of digital and analog I/O modules (SM 321, SM 331, SM 332 series) for blown fuses, loose terminal connections, or degraded signal isolation. A corrupted program image on the memory card can sometimes be traced back to an I/O fault that caused a CPU STOP condition — resolving the root cause before reloading the program prevents recurrence.

Communication and Profibus Modules: If the S7-400 system uses CP 443-1 Ethernet or CP 443-5 Profibus communication processors, confirm that their configuration data is backed up separately. Memory card replacement restores the CPU program but does not automatically restore CP module parameters stored in separate flash memory.

Terminal Blocks and Fusing: Inspect the control cabinet terminal blocks (such as Weidmüller or Phoenix Contact DIN rail terminals) and associated fuse holders for signs of overheating, loose connections, or blown protection fuses. These are frequently overlooked during memory card replacement but are a common source of secondary faults after system restart.

Site Replacement Workflow

Step 1 — Program Backup: Before removing the existing memory card, use STEP 7 or TIA Portal to upload and save the current program from the CPU to the engineering workstation. Confirm the backup is complete and readable.

Step 2 — CPU Power Down: Switch the CPU to STOP mode, then power down the S7-400 rack via the PS module main switch. Do not remove the memory card while the CPU is in RUN mode.

Step 3 — Card Removal and Inspection: Remove the 6ES7952-1AS00-0AA0 from the CPU front panel slot. Inspect the card contacts and the CPU slot for contamination or mechanical damage. Clean with dry compressed air if required.

Step 4 — Replacement Card Installation: Insert the new 6ES7952-1AS00-0AA0 firmly into the CPU memory card slot until it clicks into position. Confirm the card is fully seated before applying power.

Step 5 — Program Download: Power up the rack and switch the CPU to STOP. Download the saved program from the engineering workstation to the CPU. Verify the download completes without errors.

Step 6 — System Restart and Verification: Switch the CPU to RUN mode. Monitor the diagnostic buffer for any fault entries. Confirm all I/O modules return to normal status and the process resumes correctly before releasing the line.

This workflow is compatible with both single-CPU and H-system (redundant) S7-400 configurations. For H-systems, follow the Siemens H-system switchover procedure to avoid process interruption during the replacement.

Spare Parts Support FAQ

Q: Is the 6ES7952-1AS00-0AA0 compatible with all S7-400 CPU models?
A: The 6ES7952-1AS00-0AA0 is compatible with the SIMATIC S7-400 CPU 41x family, including the CPU 412, 414, 416, and 417 series. Compatibility with specific firmware versions should be confirmed against the Siemens hardware compatibility list for your installed CPU. KNMKS can assist with compatibility verification prior to order.

Q: How is each unit tested before shipment?
A: Every 6ES7952-1AS00-0AA0 supplied by KNMKS undergoes pre-shipment inspection covering physical condition, contact integrity, and functional verification where test equipment is available. Units are packaged in anti-static protection to prevent ESD damage during transit.

Q: What is the support terms coverage and how is it claimed?
A: All units are covered by a support terms confirmed by quotation from the date of shipment. The support terms covers defects in materials and workmanship under normal operating conditions. To initiate a support terms claim, contact [email protected] with the order reference and a description of the fault observed.

Q: Can KNMKS support long-term or multi-unit procurement for S7-400 memory cards?
A: Yes. KNMKS maintains stock and can support blanket orders, scheduled releases, and multi-unit procurement for customers managing large S7-400 installed bases or planning extended system life programs. Contact our team to discuss volume pricing and supply agreements.

© 2026 KNMKS. All rights reserved.
Original Source: https://knmks.com
Contact: [email protected] | +86 18359268345

Product Identification

Brand / Ecosystem

Siemens
Siemens

Model / Series

6ES7952-1AS00-0AA0
SIMATIC Series

Product Family

PLCs & Controllers

Availability Status

Available on request after model and quantity confirmation

Inquiry Type

B2B RFQ, replacement inquiry and project spare-part request

Pre-Quote Check

Exact SKU, brand, series, quantity, nameplate photos and destination country are checked before quotation

Specification & Inquiry Focus

Control platform

PLC, PAC and modular controllers

Common needs

CPU, rack, power and I/O expansion

Project support

Replacement, cabinet build and maintenance

Inquiry Support

• Model cross-checking before quotation
• CPU, power, rack and expansion module matching
• Support for replacement and project inquiry

What to Send Us

• Brand and exact model number: Siemens 6ES7952-1AS00-0AA0
• Quantity and required delivery time
• Application, replacement requirement or nameplate photo
• Destination country and shipping preference