6EP1931-2EC21 used Siemens powers supply Sitop 24V DC 15 ampere. Input is 24 V DC/16 ampere.
6EP1931-2EC21 used SITOP DC UPS MODULE 24 V/15 A UNINTERRUPTIBLE POWER SUPPLY WITHOUT INTERFACE INPUT: 24 V DC/16 A OUTPUT: 24 V DC/15 A
