Amazon.com: Siemens 6ES7221-1BF30-0XB0 SIMATIC S7-1200, DIGITAL INPUT SM 1221, 8DI, 24V DC, SINK/SOURCE INPUT: Home Audio & Theater
Siemens 3RH2140-1AB00 4 pole 10 AMP Control Relay with 4 N.O. and contacts and a 24 volt AC coil - Screw Terminals: Amazon.com: Industrial & Scientific
LOGO 1.3A Power Supply 115/230V to 24vdc: Electronic Components: Amazon.com: Industrial & Scientific