Description

The Siemens 6ES5951-7ND21 is a dedicated power supply module engineered for the Simatic S5-115U/H programmable logic controller (PLC) series. This unit serves as a critical component in legacy automation systems, converting an input voltage range of 19.2 to 30 VDC into a regulated 5 VDC output. Designed for high-availability industrial environments, it ensures stable power delivery to backplane components, effectively reducing the risk of system resets and unplanned downtime in critical control applications.

Features

• Designed specifically for the Simatic S5-115U/H rack-based architecture.
• Flexible output capacity: Delivers 7 A at 5 VDC as a standalone unit, or up to 15 A at 5 VDC when paired with a compatible fan subassembly.
• Optimized for high-density cabinet mounting within standard S5 rail configurations.
• Supports optional external battery integration for memory retention within the S5-115 rack environment.

Applications

This power supply module is primarily utilized in legacy industrial control systems where high-reliability power regulation is required. Common applications include petrochemical refineries, power generation plants, and large-scale mining operations where S5-115U/H systems remain in active service.

Technical Specifications

Installation Guidelines

• Ensure the PLC system is completely powered down before attempting to insert or remove the module from the rack.
• Verify that the mounting rail is properly grounded to the cabinet chassis to maintain EMI shielding.
• When high current demands are expected, ensure the appropriate fan subassembly is installed to reach the 15 A output capacity.
• Maintain adequate clearance around the module to allow for proper thermal dissipation, especially when operating at higher current loads.
• Handle with care to avoid damage to the backplane connector pins during insertion.

FAQ

Does this module include a backup battery?

No, the 6ES5951-7ND21 does not include an internal backup battery. However, it is designed to support the use of a standard size C lithium battery (such as the CA-6EW1000-7AA) for memory retention within the S5-115 rack.

Can I use this module without a fan?

Yes, the module functions as a standalone power supply providing 7 A at 5 VDC without an external fan. The fan is only required if the system configuration demands the increased 15 A output capacity.