Machine control system with machine serializing and safety circuits

• US 4,071,911 A
• Filed: 04/09/1976
• Issued: 01/31/1978
• Est. Priority Date: 04/22/1975
• Status: Expired due to Term

• Current Assignee: Continental Can Company Incorporated (Dean Foods Company)
• Original Assignee: Continental Can Company Incorporated (Dean Foods Company)
• Inventors: Mazur, Richard A.
• Primary Examiner(s): Chapnick, Melvin B.
• Application Number:
  US05/675,692
• Time in Patent Office: 662 Days
• Field of Search: 340/172.5, 340/147 C, 445/1, 235/151, 235/151.1, 235/151.11, 235/152
• US Class Current: 700/1
• CPC Class Codes: G05B 19/414 Structure of the control system, e.g. common controller or multiprocessor systems, interface to servo, programmable interface controller
• CPC Class Codes: G05B 19/4181 characterised by direct numerical control [DNC]
• CPC Class Codes: G05B 2219/33182 Uart, serial datatransmission, modem
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A plurality of multi-functioning machines are simultaneously controlled by similar transmitter/receiver pairs, one of which is associated with a programmable controller and the other of which is associated with a machine. In the controller terminal, each transmitter of one such pair transmits a series of groups of serial command signals while its receiver receives corresponding groups of serial condition-responsive signals from the machine which update the controller. In the machine terminal, the transmitter of the other pair is connected to the controller receiver and the receiver is connected to the controller transmitter. Each transmitter derives input from a multiplexing matrix and each receiver outputs its information through a demultiplexer matrix. Each transmitter/receiver pair is driven by a free-running clock but the pair associated with the machine is slaved to the controller transmitter. Provision is made for connecting a series of machine pairs to a single controller pair, and data transfer between transmitter/receiver pairs is blocked upon detection of transmission breakdown.

Claims

1. A multiplexing machine control communications system for controlling a plurality of machines from a programmable controller, comprising

a multiplexer controller terminal for receiving condition-defining information signals representing the operational functions of a plurality of independently operable multifunctioning machines and transmitting predetermined command signals to control selected functions of each of said machines,

a programmable controller coupled to said multiplexer controller terminal to provide a source of said predetermined command signals for controlling said machines in response to said condition-defining information signals,

a plurality of multiplexer machine terminals, one coupled to each one of said plurality of independently operable multifunctioning machines to transmit condition-defining information signals responsive to the operational functions of a machine coupled thereto and to receive in response thereto selected ones of said predetermined command signals,

an input and output converter coupled between said multiplexer machine terminal and a machine coupled thereto for coupling said information and command signals therbetween,

respective transmission lines for connecting said multiplexer controller terminal in parallel with each of said multiplexer machine terminals,

said multiplexer machine terminals operating independently of each other for communication between said multiplexer controller terminal and each of said multiplexer machine terminals, and

safety circuit means for monitoring the transmission of data on said transmission lines and providing inhibit signals for inhibiting data transfer within the system when transmission on said lines is interrupted.

2. A system as in claim 1 including time delay means in said machine terminal for providing time delay at turn on of the said machine terminal for assuring that the machine terminal is in synchronism with the controller terminal before data is processed by the machine terminal.

3. A system as in claim 2 wherein said time delay means includes

a capacitor which begins to charge when the system is turned on and reaches a preset level of charge at a predetermined time after turn on,

gating devices connected to said capacitor for controlling the transfer of data through associated machine terminals,

said gating devices having distinct operating states responsive to the charge on said capacitor, and

said gating devices being shifted to an operating state for allowing data to pass therethrough only after said capacitor is charged to said preset level.

4. A system as in claim 1 wherein said safety circuit includes

capacitor storage means coupled to said transmission lines to be charged thereby during transmission of data signals,

means coupling said capacitor storage means to said transmission lines for discharging said capacitor storage means upon termination of data transmission, and

gate means coupled to said capacitor storage means for selectively gating the transmission of data signals through said transmission lines in response to the charge on said capacitor storage means.

5. A system as in claim 1 wherein said safety circuit includes

capacitor storage means for storing a charge in response to the transmission of data through said transmission lines,

means for discharging said capacitor storage means upon the interruption of transmission of data through said transmission lines,

gate means having first and second operating states connected to said capacitor means for selectively enabling the inhibiting transmission of data through said transmission lines in response to the level of charge on said capacitor storage means,

said first operating state of said gate means gating the transmission of data to and from said transmission lines, and

said second operating state of said gate means inhibiting the transmission of data to and from said transmission lines.

6. A system as in claim 4 wherein said safety circuit further includes manual reset means for manually controlling the resumption of operation of said system coupled to said gate means to enable the re-establishing of data transmission through said transmission lines upon the charging of said capacitor storage means to a predetermined level.

7. A system as in claim 4 wherein said safety circuits include shift register means coupled to said capacitor storage means, and

said shift register means being resettable in response to continuing data input through said transmission lines to the associated terminal for maintaining a predetermined charge on said capacitor storage means sufficient to enable continuous transfer of data.

8. A system as in claim 4 further including time delay means in said multiplexer machine terminal for providing time delay at turn on of said machine terminal for assuring that the machine terminal is in synchronism with the controller terminal before data is processed by the machine terminal, and

manual reset means for manually controlling the resumption of operation of said system coupled to said gate means to enable the re-establishing of data transmission through said transmission lines upon the charging of said capacitor storage means to a predetermined level to control the state of said gate means to re-establish data transmission through said transmission lines.

9. A system as in claim 2 wherein said safety circuit means includes

capacitor storage means coupled to said transmission lines to be charged thereby during transmission of data signals,

means coupling said capacitor storage means to said transmission lines for discharging said capacitor storage means upon termination of data transmission, and

gate means coupled to said capacitor storage means for selectively gating the transmission of data signals through said transmission lines in response to the charge of said capacitor storage means.

10. A system as in claim 9 further including manual reset means for manually controlling the resumption of operation of said system coupled to said gate means to enable the re-establishing of data transmission through said transmission lines upon the changing of said capacitor storage means to a predetermined level to control the state of said gate means to re-establish data transmission through said transmission lines.

11. A machine control communication system for controlling a plurality of machines from a programmable controller operating with a scan cycle of a plurality of distinct periods, comprising

a multiplexer controller terminal for receiving condition-defining information signals representing the operational functions of a plurality of independently operable multifunctioning machines and for transmitting predetermined command signals to control selected functions of each of said machines,

a programmable controller coupled to said multiplexer controller terminal to provide a source of said predetermined command signals for controlling said machine functions in response to said condition-defining information signals,

a plurality of multiplexer machine terminals, one coupled to each one of said plurality of independently operable multifunctioning machines to transmit condition-defining information signals responsive to the operational functions of a machine coupled thereto and to receive selected ones of said predetermined command signals,

an input and output converter coupled between each multiplexer machine terminal and a machine coupled thereto for coupling said information and command signals therebetween,

transmission lines connecting said multiplexer controller terminal with each of said multiplexer machine terminals for enabling communication between said multiplexer controller terminal and each of the multiplexer machine terminals,

a dependent multiplexer machine terminal serially connected with one of said multiplexer machine terminals to said multiplexer controller terminal,

said dependent multiplexer machine terminal being operable in series with said one multiplexer machine terminal, and

switch means for controlling the transmission and receipt of said signals from said one multiplexer machine terminal positionable to determine which of said serially connected multiplexer machine terminals is to operate during a given period of the scan cycle.

12. A communication system as in claim 11 wherein said switch means comprises a plurality of input lines each selectively receiving enabling signals during a given period of each scan cycle and an equal number of output lines for coupling signals therebetween,

a plurality of switches for coupling each inout line to a respective one of said output lines to couple said enabling signals thereto,

gate means connected to said output lines for coupling the output signals thereon as a single output signal from said gate means,

first and second logic circuit means respectively associated with said one and said dependent machine terminals and coupled to said gate means to be selectively energized thereby, and

said first and second logic circuit means being selectively energized during a selected period of said scan cycle by said output signal from said gate means when transmitting data from said multiplexer machine terminal asociated therewith.

13. A communication system as in claim 11 wherein said switch means comprises a switch assembly including a plurality of individual switches, each of said switches being connected in the operating circuit and sequentially actuable during a particular period of each scan cycle.

14. A communication system as in claim 13 wherein the closure of an individual switch couples a succeeding dependent multiplexer machine terminal to enable transmission from said succeeding dependent terminal and disconnects the preceding multiplexer control terminals.

15. A communications system as in claim 13 including means for selectively addressing incoming data to each multiplexer terminal and the selection of transmission from a particular multiplexer machine terminal in a series is determined by the position of the respective individual switch associated with the selected period of the scan cycle.

16. A communication system as in claim 13 wherein said switch assembly is connected to a decoder which establishes the period of the scan cycle wherein information is transmitted by a dependent multiplexer machine terminal.

17. A communication system and as in claim 13 wherein the individual switches defining each transmission period of the scan cycle are closed when a succeeding multiplexer machine terminal is to transmit information and wherein said individual switches are open when the multiplexer machine terminal in which said switch means are located is to transmit data.

18. A communication system and as in claim 17 wherein individual transmission periods are varied dependent on said switch means.