plc BECKHOFF BECKHOFF PLC bus terminal DIGITAL DIGITAL OUTPUT KL2114 KL 2114 BECKHOFF ANALOG MODULE PLC KL2408 BECKHOFF KL2408 BECKHOFF KL 2408 ANALOG MODULE PLC KL2408 BECKHOFF PLC KL2408 BECKHOFF KL2114 beckhoff kl-2114 beckhoff 2114 kl2114 relay output beckhoff kl2114 4 channel beckhoff kl2114 4ch relay output