Sorry, don’t use NodeRed, but, from what I remember, others have implemented and posted here flows that call a command line utility and parse the result. Search for vreg.
LE:
Like this implementation here: Switching a relay on an MPPT charge controller using Node-Red on RPi - #46 by roeller
Only that the command, for VE.CAN, would be:
For disable: vreg -c socketcan:can0 -n xxx -s 0xD0E0 0
For enable: vreg -c socketcan:can0 -n xxx -s 0xD0E0 1
Where xxx is the network address of your Multi RS.
Also, the CAN network could be different, depending on where you have the Multi RS connected.