Drive-to-drive link 349Drive-to-drive linkWhat this chapter containsThe chapter describes the communication on the drive-to-drive link.GeneralThe drive-to-drive link is a daisy-chained RS-485 transmission line, constructed byconnecting the XD2D terminal blocks of the JCU control units of several drives. It isalso possible to use an FMBA Modbus adapter module installed into an option slot onthe JCU. The firmware supports up to 63 nodes on the link.The link has one master drive; the rest of the drives are followers. By default, themaster broadcasts control commands as well as speed and torque references for allfollowers. The master can send 8 messages per millisecond at 100/150-microsecondintervals. Sending one message takes approximately 15 microseconds, which resultsin a theoretical link capacity of roughly 6 messages per 100 microseconds.Multicasting the control data and reference 1 to a pre-defined group of drives ispossible, as is chained multicast messaging. Reference 2 is always broadcast by themaster to all followers. See parameters 57.11…57.14.Note: The drive-to-drive link can be used only if the embedded fieldbus interface isdisabled (see parameter 58.01 Protocol ena sel). WiringSee the Hardware Manual of the drive.
