SITOP PSE201U buffer module Buffer time 100 ms to 10 s depending on load current, E-Stand: 01. SITOP PSE201U buffer module Buffer time: 100 ms to 10 s depending on load current E-Stand: 01 6EP1961-3BA01 Siemens is a reliable power supply unit suitable for various industrial applications. It can be purchased at PLC2Day for all your power supply needs in industrial settings.