It is my understanding that the MAJ does a velocity move with the expectation that the motion will be stopped with an MAS instruction.
In that case, the RMC’s Move Velocity (37) command can be used, as it does the same thing. The Stop (Closed-Loop) (6) command can be used to stop the axis. As an alternative to the Move Velocity (37) command, you can use the Move Absolute (20) command, which also move the axis at some velocity, but includes a stopping position, which can ensure the axis stops even if the stop command isn’t sent for some reason.
Are you familiar with the AOI’s that Delta has developed? There is a project in this topic that contains the AOIs: https://forum.deltamotion.com/t/converting-from-hyd02-m02as-and-m02ae-to-the-rmc/1206. I believe it contains an AOI to mimic the MAJ instruction.
-Jacob