Siemens 6ES5951-7LD21 is a SIMATIC S5 951 power supply module designed to power older S5 control racks, such as the S5-115U/H. It accepts a 120–230 VAC input, aligning with common mains standards for field installations, and provides the necessary backplane power for the 951 family of devices. This module is typically employed in repair, refurbishment, or expansion scenarios where continued operation of existing S5 systems is required and a 951 power supply is specified.
