Multifunction Relay
Using two multifunction relays, each Sunny Island can control various functions and can display operating states and warning messages.
In an SMA Flexible Storage System with battery-backup function, the multifunction relays of the master are set permanently.
In multicluster systems with Multicluster-Box 12 (MC-BOX-12.3-20), multifunction relays 1 and 2 in the master of the main cluster and multifunction relay 2 in slave 1 of the main cluster are set permanently.
Possible function or output | Explanation |
|---|---|
Control of the tie switch and of the contactors for grounding | In the SMA Flexible Storage System with battery-backup function, the multifunction relays control the contactors for grid coupling and grounding. |
Switch cycles in the multicluster system | In multicluster systems with Multicluster-Box 12, multifunction relays control different switch cycles in the multicluster system. |
Controlling PV arrays | The multifunction relay activates if a PV array request is received from the Sunny Island inverter's generator management system. With the multifunction relay, you can control PV arrays with an electrical remote-start function or connect a signal generator for PV arrays with no autostart function ( > Connecting the Control Cable for Autostart Generators). |
Controlling load-shedding contactors | The multifunction relay is activated depending on the state of charge of the battery. Depending on the configuration, you can install a one-level load shedding with one multifunction relay or a two-level load shedding with two multifunction relays. You can also adjust the thresholds for the state of charge of the battery depending on the time of day ( > Connecting Load-Shedding Contactors). |
Time control for external processes | The multifunction relays can be time-controlled ( > Connecting the Time Control for External Processes). |
Display of operating states and warning messages | Each multifunction relay can display either one event or one warning message ( > Connecting Message Devices for Operating States and Warning Messages). |
Control of a battery-room fan | The multifunction relay is activated when the charging current causes the battery to emit gasses. A connected battery room fan is switched on for at least one hour ( > Connecting the Battery Room Fan). |
Control of an electrolyte pump | Depending on the nominal energy throughput, the multifunction relay is activated at least once a day ( > Connecting the Electrolyte Pump for the Battery). |
Use of excess energy | In off-grid systems with lead-acid batteries during the constant voltage phase, a multifunction relay is activated and thus controls additional loads that can put any excess energy to good use ( > Connecting the Control Cable for the Use of Excess Energy in an Off-Grid System). |