The KNC-PLC-KS122 series Expansion Modules can be attached to the KNC-PLC-KS CPUs or the KNC-HMI-MK HMI/PLC combo units to expand the I/O beyond the onboard inputs and outputs. The KNC-PLC-KS series can handle a maximum of 14 expansion modules while the KNC-HMI-MK can handle 8 modules. Available modules include Digital Outputs Only with Relay or Source Output Types. Each expansion module allows for a distributed installation using a standard Ethernet cable from unit to unit.