Mine

loadrt ddt names=dx,dy,dz,ddx,ddy,ddz
loadrt hypot names=xyvel,xyzvel

newsig Xvel float
newsig Xacc float
linksp Xpos => dx.in
linkps dx.out => Xvel
linksp Xvel => ddx.in
linkps ddx.out => Xacc
newsig Yvel float
newsig Yacc float
linksp Ypos => dy.in
linkps dy.out => Yvel
linksp Yvel => ddy.in
linkps ddy.out => Yacc
newsig Zvel float
newsig Zacc float
linksp Zpos => dz.in
linkps dz.out => Zvel
linksp Zvel => ddz.in
linkps ddz.out => Zacc

newsig XYvel float
linksp Xvel => xyvel.in0
linksp Yvel => xyvel.in1
linksp XYvel <= xyvel.out
newsig XYZvel float
linksp Zvel => xyzvel.in0
linksp XYvel => xyzvel.in1
linksp XYZvel <= xyzvel.out