EXTERNAL EXTENSION TYPE PROGRAMMABLE CONTROLLER

Abstract: This invention relates to an external extension type programmable controller wherein part of the control functions are made independent externally. This controller comprises a main PMC (programmable machine controller) unit (2) incorporated in a numerical controller (CNC) (1) and controlled on the basis of the instruction of the numerical controller (1), an input/output unit (3) connected to the main PMC unit (2) and transferring signals to/from a mechanical unit A (61) and an extended PMC unit connected to the main PMC unit (2) through the input/output unit (3) and controlling a mechanical unit B (62) with its own sequence program. The extended PMC unit (4) stores by itself the sequence program relating to the mechanical unit B (62) to be controlled and controls the machine by performing transmission and reception of instructions and various data with the main PMC unit (2) through communication means (5).

Description: TECHNICAL FIELD The present invention relates to an externally extended type programmable controller in which a part of the control functions thereof is independently provided as an external unit, and more specifically, to an externally extended type programmable controller in which a control function of a sequence program regarding particular mechanical units is independently provided as an external unit. BACKGROUND ART Two kinds of programmable controllers (PC) are generally used: one as an independent unit; and the other as a unit contained in a numerically controlled apparatus (CNC). Hereinafter, the PC contained in the numerically controlled apparatus is referred to as a programmable machine controller (PMC). Figure 3 is a wiring diagram of a conventional PMC, in which a PMC 20 is contained in a numerically controlled apparatus 10. A sequence program for controlling the particular operations of mechanical units A 61 and B 62 is stored in the PMC 20 and controls the mechanical unit A 61 through an I/O circuit 31 and the mechanical unit B 62 through an I/O circuit 32 in response to a command. The operation of some of the mechanical units controlled by the PMC 20 for example, an automatic pallet changer (APC), loader and the like, are independently effected, because a sequence program, for example, controlling these mechanical units can be more easily debugged when they are handled independently. Nevertheless, when a sequence program for all of the wired mechanical units is stored in the PMC 20, as in prior art, all of the mechanical units must be wired when debugging is carried out. Further, when another mechanical unit is to be added later, a necessary modification of the sequence program is very cumbersome. EP-A-0187677 discloses a programmable controller linking system with master controller. GB-A-2064920 discloses an industrial communications network for process controllers. Taking the above into consideration, an object of the present invention is to provide an externally extended type programmable controller in which a control function of a sequence program regarding particular mechanical units is independently provided as an external unit. To solve the above problem, in accordance with the present invention, there is provided an externally extended programmable controller, in which part of the control function is independently provided as an external unit, the controller comprising: a main programmable controller; an extended PC connected to said main PC for controlling a particular mechanical unit by an independent sequence program; and communication means for connecting said main PC and said extended PC; characterised in that: the main PC is contained in a numerically controlled apparatus and controlled in response to a command from the numerically controlled apparatus; and the communication means includes an I/O unit contained in said numerical controlled apparatus, said I/O unit being connected to said main PC for transmitting and receiving signals to and from a predetermined mechanical unit. The extended PC independently stores the sequence programs for the mechanical units to be controlled, and controls the mechanical units by transmitting and receiving commands and various data to and from the main PC through a communication means. A connection of a program creating device to the extended PC enables programs to be input, edited and debugged therefrom. In the drawings:- Figure 1 is a wiring diagram of an embodiment of an externally extended programmable controller according to the present invention; Figure 2 is a block diagram showing the inner arrangement of an extended PMC in the embodiment according to the present invention; and Figure 3 is a wiring diagram of a conventional PMC. BEST MODE OF CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a wiring diagram of an embodiment of an externally extended programmable controller according to the present invention, wherein a numerically controlled apparatus 1 contains the main PMC 2 of a main PC. The main PMC 2 stores a sequence program for a mechanical unit A 61 and controls the operation of the mechanical unit A 61 through an I/O circuit 3, in response to commands. On the other hand, an extended PMC 4 of an extended PC independently stores a sequence program for a mechanical unit B 62 and control same by transmitting and receiving commands and various data to and from the main PMC 2 through a communication line 5. Usually, the extended PMC 4 is provided in the mechanical unit B 62. Figure 2 is a block diagram showing the inner arrangement of the extended PMC 4. The extended PMC 4 comprises a communication interface 41 composed of an RS 422 or RS 232C for communicating with the main PMC, a processor 42 for controlling the operation as a whole, a ROM 43 in which a control program is stored, a RAM 44 in which a sequence program for the mechanical unit is stored, an I/O circuit 45 for transmitting and receiving signals to and from the mechanical unit, and a programmer's interface 46 to which a portable program creation device is connected. Note that the communication interface 41 may be contained in the processor 42. The processor 42 executes an arithmetic operation and processing in accordance with the sequence program stored in the RAM 44 in response to commands and various data transmitted from the PMC through the communication interface 41 and signals input from the mechanical units, and outputs signals to thereby control the mechanical units. Further, the processor 42 transmits the result of the processing to the main PC as data. In addition, a connection of the portable program creation device to the programmer's interface 46 enables the sequence program stored in the RAM 44 to be debugged and a new sequence program to be input and edited. As described above, according to the present invention, a function for controlling the sequence program for particular mechanical units is independently provided as the externally extended PC and connected to the main PC through the communication line, and thus the sequence program can be debugged for each mechanical unit, for example, an APC, loader and the like. Further, when an other mechanical unit is provided later, the sequence program can be easily modified. Furthermore, since the function for controlling the main PC is not used, the overall processing speed can be improved.

Claims: An externally extended programmable controller (PC), in which part of the control function is independently provided as an external unit, the controller comprising: a main programmable controller (PC) (2) ; an extended programmable controller (PC) (4) connected to said main programmable controller (PC) for controlling a particular mechanical unit (62) by an independent sequence program; and communication means (3,5) for connecting said main programmable controller (PC) and said extended programmable controller (PC); characterised in that: the main programmable controller (PC) (2) is contained in a numerically controlled apparatus (CNC) (1) and controlled in response to a command from the numerically controlled apparatus (CNC); and the communication means (3,5) includes an I/O unit (3) contained in said numerical controlled apparatus, said I/O unit being connected to said main programmable controller (PC) (2) for transmitting and receiving signals to and from a predetermined mechanical unit (61). A controller according to claim 1, wherein said extended programmable controller (PC) (4) comprises: a processor (42); a communication interface (41) connecting said processor to said communication means; a memory (43) in which a control program is stored; a memory (44) in which a sequence program for said particular mechanical unit is stored; an I/O circuit (45) for transmitting and receiving signals to and from said particular mechanical unit (62); and an interface (46) connecting said processor to an external program creation device.

Inventors: SAKAGAMI AKIRA, YAMAUCHI TAKASHI, SAKAGAMI, AKIRA, YAMAUCHI, TAKASHI, SAKAGAMI, AKIRA FANUC MANSION HARIMOMI 6-106, YAMAUCHI, TAKASHI FANUC MANSION HARIMOMI 6-202
Applicants: FANUC LTD, FANUC LTD.
Application year: 1990
Main classification: G05B19
IPC codes: G05B19