If all the needles, or a block of needles, were to be simultaneously selected, each would require its own actuator. It is much cheaper to select the needles at a single selection position in serial formation, using between one and six actuators, although the time interval between each selection impulse is shorter.
This sentences have been recited from Knitting Technology by David J Spencer. I think using between one and six actuators means first and sixth actuators are not used, rather second, third, fourth and fifth actuators are used.
Please say what it actually means.