JPS57555A - Retreat detector - Google Patents

Abstract

PURPOSE:To detect retreat accurately by measuring retreat distance by the use of an up-down counter in a driving system for new traffic system vehicles. CONSTITUTION:Two speed pulses A, B are of such a phase relation that during advancing A is in phase advance by 90 deg. than B and the trailing edge of A and B superpose and that during retreating A is in phase delay by 90 deg. than B and the leading edge of A superposes on B. Pulses are outputted to F during advancing and to E during retreating by way of an inverter 1, differentiators 2, 3 and AND gates 4, 5. When an advance direction select switch 14 is at the advancing TF, a binary up- down counter circuit 15 down counts by an up-down control terminal UD, and when the count value from a clock pulse input terminal CK goes 0, the counting is stopped by a borrow terminal BR. In the case of the retreat time TB, the circuit 15 up count, and when the count value of the counter 15 attains the value of a set switch 17, a retreat signal is obtained from the output terminal OUT of a binary comparator 16.