diff_h(), diff_k(), diff_l(), fc_qx(), fc_qy(), fc_qz(), fc_psi()

diff_h()
diff_h() = value
diff_k()
diff_k() = value
diff_l()
diff_l() = value
diff_psi()
fc_qx()
fc_qx() = value
fc_qy()
fc_qy() = value
fc_qz()
fc_qz() = value
fc_psi()
fc_psi() = value

Moves to/returns h, k, l, psi.

e.g.:
* = diff_h()
diff_l() = 1

Note that there is the command move/h=.../k=... which moves the diffractometer to a point in q-space, with all motors driving simultaneously.