GB1467406A - Counting circuit - Google Patents

Abstract

1467406 Predetermined counters HINKELMANN GmbH 23 March 1974 [23 March 1973] 12937/74 Headings G4A and G4D A predetermined counter uses a multiplexing arrangement to compare the count in a counter 201-203 with a value stored in a store 215 and issue a signal after a preselected number of pulses has been counted. The m-stage counter 201-203 has m binary coded decimal outputs 204-206 which are scanned cyclically and fed in succession to the output 200 under the control of a high speed clock 208. The individual releasing signals 210-212 being used also to operate the respective stage of an m-stage display 213 coupled to the output of the multiplexer and to release the respective digit from the store 215 to a comparator 221. When a digit in counter 201-203 corresponds to the respective value stored in 215 comparator delivers a pulse to a counter 225. Counter 225 is reset to zero after each cycle of the multiplexer (every m pulses of clock 208) by a divider 226. If counter 225 reaches a count of m before being reset, signifying, coincidence between the count and stored value it delivers an output pulse via a gate 239 and inhibits further input pulses by gate 231. In a modification (Fig. 5, not shown) the counter 225 &c. is replaced by a group of m bi-stable one of which is set for each coincident digit; when all are set an output pulse appears; also in this circuit three separate stores (316, 317, 318) 215 are shown with a programmer 320 for selecting them in sequence. In a third embodiment (Fig. 6, not shown) the inputs and outputs of all units within the module 243 are controlled by a common switching circuit (359) controlled by a decoder from a b.c.d. input signal allowing the module 243 to have various operating modes (not described). Various auxiliary circuits are described (Figs. 3a-3c, 7, 8, not shown) for use at the input, output and reset terminals of the module 243 to allow it to control an output relay in various ways, namely to energize the relay at the start of an input pulse and open it after the preselected number of clock pulses have been counted; to energize the relay at the start of the pulse and keep it energized until the number of clock pulses have elapsed after the end of the input pulse; or to energize the relay after the number of pulses is counted from the start of the input pulse and de-energize at the end of the pulse (Fig. 2, not shown). The module 243 may be made as an integrated circuit.