One for each SI Cluster Master.
The SMA MC-PB multicluster piggyback board is designed to retrofit the Sunny Island inverters for communications capability with the multicluster box. Utilizing a controller area network (CAN) and RS485 this card enables communication between the main cluster and extension clusters. It also allows the Sunny Island inverters to communicate with other SMA inverters and communications devices. The MC-PB is compatible with the SI4545-US-10, SI5048-US, and the SI6048-US-10.