42 in the left takeup position as viewed in fig1 toward the inside of the right flange when the initial pulse is received by the microprocessor 301 from the zl sensor 303 and assuming the distributor 201 is in the left mode as seen in fig1 the distribution counter which has been preloaded with the number n is reset to n and begins to count down the number n represents the number of pulses required to advance the distributor 201 from the zero left position to the inside of the spool flange each count down is a function of each motor pulse received and after the distributor 201 has been moved a specific distance toward the right flange of a spool 42 the counter sends a signal to the microprocessor 301 to indicate that right flange count down has been achieved as a result of having received that signal the microprocessor 301 controls the interface circuitry to cause the motor 207 to turn in an opposite direction through one of the inputs 378 or 379 to the stepper drive system 370 to move the distributor 201 toward the left flange at the same time the distribution counter is reset to the same starting reference number n the distributor 201 is moved by the rotation of the lead screw 204 and after it passes the interruptor 303 a signal is sent to the microprocessor 301 to cause the counter to begin its count down toward the left flange of the spool in the left hand takeup position as viewed in fig1 the control system 300 of this invention can be adjusted in that the distribution count which is loaded into a register in the microprocessor 301 can be decremented selectively in order to.