Program features 75 External controller interfaceGeneralThe drive can be connected to an external controller (such as the ABB AC 800M)using either fiber optic or twisted-pair cable. The ACS880 is compatible with both theModuleBus and DriveBus connections. Note that some features of DriveBus (such asBusManager) are not supported.TopologyAn example connection with either a ZCU-based or BCU-based drive using fiber opticcables is shown below.Drives with a ZCU control unit require an additional FDCO DDCS communicationmodule; drives with a BCU control unit require an RDCO or FDCO module. The BCUhas a dedicated slot for the RDCO – an FDCO module can also be used with a BCUcontrol unit but it will reserve one of the three universal option module slots. Ring andstar configurations are also possible much in the same way as with themaster/follower link (see section Master/follower functionality on page 68); thenotable difference is that the external controller connects to channel CH0 on theRDCO module instead of CH2. The channel on the FDCO communication modulecan be freely selected.The external controller can also be wired to the D2D (RS-485) connector usingshielded, twisted-pair cable. The selection of the connection is made by parameter60.51 DDCS controller comm port.The transfer rate can be selected by parameter 60.56 DDCS controller baud rate.CommunicationThe communication between the controller and the drive consists of data sets of three16-bit words each. The controller sends a data set to the drive, which returns the nextdata set to the controller.T = Transmitter; R = ReceiverACS880(BCU) Control unitRDCOCH0ControllerRT RTACS880(ZCU) Control unitFDCORT
