Programmable controller

• US 4,292,666 A
• Filed: 04/12/1978
• Issued: 09/29/1981
• Est. Priority Date: 04/12/1978
• Status: Expired due to Term

• Current Assignee: Schneider Automation Incorporated (Schneider Electric SE)
• Original Assignee: Gould Incorporated Modicon DIV
• Inventors: Hill, Lawrence W., Malcolm, Ronald, Stoodley, Thomas J. III
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US05/895,581
• Time in Patent Office: 1,266 Days
• Field of Search: 364/104, 364/107, 364/120, 364/200 MS File, 364/900 MS File
• US Class Current: 700/18
• CPC Class Codes: G05B 19/05 Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
• CPC Class Codes: G05B 2219/13004 Programming the plc
• CPC Class Codes: G05B 2219/15078 Modules, construction of system
• CPC Class Codes: G05B 2219/15107 Linesolver, columnsolver

Abstract

A small, low cost, programmable controller is described capable of solving user programs represented in networks having up to seven rows and eleven columns. A column solver is utilized to provide efficient and fast solution of the user control network. The programmable controller also solves calculate functions having multiple outputs to facilitate use of the output information in the control program.

A programming panel using a CRT display shows one or more selected control networks and, in conjunction with the central processing unit of the programmable controller, provides for the insertion of networks between two existing networks. Since the networks are solved by the controller mainframe in a sequential fashion, this network insertion allows the user to optimize his or her control program when solution order of the networks is important.

The output coil numbers of network rows may also be assigned by the user independent of their placement in the control program to further facilitate programming the controller. The programming panel includes a movable cursor on the CRT display which, in conjunction with a light-emitting diode (LED), allows the user to monitor the real-time power flow at any particular point in the displayed ladder diagram network. Specialized search features can also be specified by the user to simplify monitoring and de-bugging the control program.

Claims

1. An improved programmable controller of the type having a mainframe including a central processing unit, associated electronics and memory for solving a user control program, an input/output system for communicating input data from external devices to the mainframe and for transferring output data from the mainframe to the external devices for control thereof in response to the control program, and a programming panel for programming, monitoring and displaying the user selected control program, wherein the improvement comprises:

(A) an improved programming panel having first means for allowing the user to generate a control program in a network format, each network comprising up to I rows and J columns, where I and J are positive integers each greater than one, each network comprising up to I×

J nodes where the location of each node is N_ij, were i=1, 2 . . . I, j=1, 2, . . . J, and where each of at least some of these nodes are designatable by the user as representing an electrical circuit element that can reference other nodes, and having a power output status that is a function of the input power status to the node in combination with the conductivity status of the element, and having second means for allowing the user to generate vertical interconnections between the output of node N_i,j with the output of node N_i-1,j or with output of node N_i+1,j, for all existent nodes N_i-1,j and N_i+1,j, where "or" is used in the inclusive sense, and wherein the power input status from node N_i,j to node N_i,j+1 is represented by the following Boolean equation;

space="preserve" listing-type="equation">P.sub.IN.sbsb.i,j =P.sub.OUT.sbsb.i,j +P.sub.VU.sbsb.i,j +P.sub.VD.sbsb.i,j (

     1)

where

space="preserve" listing-type="equation">P.sub.OUT.sbsb.i,j =P.sub.IN.sbsb.i,j-1 ·

C.sub.i,j (

     2)

where C_i,j is the conductivity state of node N_i,j,

where

space="preserve" listing-type="equation">P.sub.VU.sbsb.i,j =P.sub.IN.sbsb.i+1,j ·

C.sub.U.sbsb.i,j (

     3)

where C_U.sbsb.i,j is the connectivity state between the output of node N_i,j and node N_i+1,j

where

space="preserve" listing-type="equation">P.sub.VD.sbsb.i,j =P.sub.IN.sbsb.i-1,j ·

C.sub.D.sbsb.i,j, (

     4)

where C_D.sbsb.i,j is the connectivity state between the output of node N_i,j and node N_i-1,j ;

and where P_IN.sbsb.i,0 is equal to logic true; and

(B) an improved mainframe having means for simultaneously solving equation (1) for each node in each column of the user generated network on a column by column basis.

7. An improved programmable controller as defined in claim 1, wherein the mainframe means for solving equation No. 1 comprises (a) a first series of logic gates, the output of the first logic gates representing the Boolean state of P_IN simultaneously for each row i and sequentially for each column j, (b) a second series of logic gates, each second series gate receiving as one input the P_OUT state for the corresponding node in the network, the output of each second series gate connected as a first input to the corresponding first series gate, (c) a third series of logic gates, each third series gate receiving as one input the connectivity state between the present node and the node in the previous row and the same column, and as a second input the output of the second series gate in the previous row, if present, the output of each third series gate connected as a second input to the next row second series gate, (d) a fourth series of logic gates, each fourth series gate receiving as one input the P_OUT state for the corresponding node in the network, the output of each fourth series gate connected as a second input to the corresponding first series gate, and (e) a fifth series of logic gates, each fifth series gate receiving as one input the connectivity state between the present node and the node in the next row and the same column, and as a second input the output of the fourth series gate for the next row, the output of each fifth series gate connected to the corresponding fourth series gate as a second input

2. An improved programmable controller of the type having a mainframe including a central processing unit, associated electronics and memory for solving a user control program, and input/output system for communicating input data from external devices to the mainframe and for transferring output data from the mainframe to the external devices for control thereof in response to the control program, and a programming panel for programming, monitoring and displaying the user selected control program, wherein the improvement comprises:

(A) an improved programming panel having first means for allowing the user to generate a control program in a network format, each network comprising up to I rows and J columns, where I and J are positive integers each greater than one, each network comprising up to I×

J nodes where the location of each node is N_ij, where i=1,2, . . . I, j=1,2, . . . J, and where each of at least some of these nodes are designatable by the user as representing an electrical circuit element that can reference other nodes, and having a power output status that is a function of the input power status to the node in combination with the conductivity status of the element, and having second means for allowing the user to generate vertical interconnections between the output of node N_i,j with the output of node N_i-1,j or with output of node N_i+1,j, for all existent nodes N_i-1,j and N_i+1,j, where "or" is used in the inclusive sense, and wherein the power input status from node N_i,j is represented by the following Boolean equation;

space="preserve" listing-type="equation">P.sub.IN.sbsb.i,j =P.sub.OUT.sbsb.i,j +P.sub.OUT.sbsb.i-1,j ·

C.sub.V.sbsb.i,j +P.sub.OUT.sbsb.i-2,j ·

C.sub.V.sbsb.i-1,j ·

C.sub.V.sbsb.i,j + . . . +P.sub.OUT.sbsb.1,j ·

C.sub.V.sbsb.2,j ·

C.sub.V.sbsb.3,j . . . C.sub.V.sbsb.i,j +P.sub.OUT.sbsb.i+1,j ·

C.sub.V.sbsb.i+1,j +P.sub.OUT.sbsb.i+2,j ·

C.sub.V.sbsb.i+2,j ·

C.sub.V.sbsb.i+1,j + . . . +P.sub.OUT.sbsb.I,j ·

C.sub.V.sbsb.I,j C.sub.V.sbsb.I-1,j . . . C.sub.V.sbsb.i+1,j (

     1)

where

space="preserve" listing-type="equation">P.sub.OUT.sbsb.i,j =P.sub.IN.sbsb.i[-1],j-1 ·

C.sub.i,j (

     2)

where C_i,j is the conductivity state of node N_i,j, where C_V.sbsb.i,j is the connectivity state between node N_i,j and node N_i-1,j, and where P_IN.sbsb.i,0 is equal to logic true; and

(B) an improved mainframe having means for simultaneously solving equation (1) for each node in each column of the user generated network on a column by column basis.

8. An improved programmable controller as defined in claim 2, wherein the mainframe means for solving equation 1 is performed by a group of logic gates which solve the P_IN status simultaneously for each row i and in a sequential manner for each column j.

3. An improved programmable controller of the type having a mainframe including a central processing unit, associated electronics and memory for solving a user control program comprising a plurality of nodes in a network format, the nodes representing user selectable circuit elements that can reference other nodes, an input/output system for communicating input data from external devices to the mainframe and for transferring output data from the mainframe to the external devices for control thereof in response to the control program, and a programming panel for programming, monitoring and displaying on a cathode ray tube (CRT) at least a portion of the user selected control program, wherein the improvement comprises an improved programming panel and mainframe each having interacting means for performing one of a plurality of search functions containing one or more search parameters as designated by the user so as to display on the programming panel CRT the control program network satisfying the search parameters, wherein the search parameters that can be designated by the user include the searching for the first node of a network, the searching for the first occurrence of a particular contact type of a particular circuit element, the searching for the first occurrence of a particular reference number, the searching for the first occurrence of a particular circuit element having a particular reference number, and the searching for the first occurrence of a particular node.

4. An improved programmable controller as defined in claim 3, wherein the improved programming panel has means allowing the user to generate vertical interconnections between the output of two nodes in adjacent rows of the network, and wherein the search parameters that can be designated by the user include the searching for the first occurrence of a vertical connector, the searching for the first occurrence of a particular contact type of a particular circuit element having a vertical connector and the searching for the first occurrence of a particular reference number having a vertical connector.

5. An improved controller of the type having a mainframe including a central processing unit, associated electronics and memory for solving a user control program comprising a plurality of nodes, an input/output system for communicating input data from external devices to the mainframe and for transferring output data from the mainframe to the external devices for control thereof in response to the control program, and a programming panel, including a screen display with a refresh rate for the screen information, for programming, monitoring and displaying at least a portion of the user selected control program, wherein the improvement comprises an improved programming panel and mainframe wherein the programming panel has a visual screen display and a cursor which can be moved from node to node of the control program as displayed on the visual display, and wherein the programming panel further includes means for indicating to a user the real-time power status of the node upon which the cursor is placed independent of the screen refresh rate.

6. An improved programmable controller as defined in claim 5, wherein the real-time power status indicating means is a light and means for energizing the light in response to the real-time power status of the node.

9. An improved programmable controller of the type having a mainframe including a central processing unit, associated electronics and memory for solving a user control program comprising a plurality of nodes in a network format, the nodes representing user selectable circuit elements that can reference other nodes, an input/output system for communicating input data from external devices to the mainframe and for transferring output data from the mainframe to the external devices for control thereof in response to the control program, and a programming panel for programming, monitoring and displaying on a screen at least a portion of the user selected control program, wherein the improvement comprises an improved programming panel and mainframe each having interacting means for performing one or more search functions containing one or more search parameters as designated by the user so as to display on the programming panel screen the control program network satisfying the search parameters, wherein the search parameters that can be designated by the user include one or more of the following:

the searching for the first node of a network, the searching for the first occurrence of a particular contact type of a particular circuit element, the searching for the first occurrence of a particular reference number, the searching for the first occurrence of a particular circuit element having a particular reference number, and the searching for the first occurrence of a particular node.

10. An improved programmable controller as defined in claim 9, wherein the improved programming panel has means allowing the user to generate vertical interconnections between the output of two nodes in adjacent rows of the network, and wherein the search parameters that can be designated by the user include one or more of the following:

the searching for the first occurrence of a vertical connector, the searching for the first occurrence of a particular contact type of a particular circuit element having a vertical connector, and the searching for the first occurrence of a particular reference number having a vertical connector.

11. An improved programmable controller as defined in claims 9 or 10, wherein the means for performing one or more search functions examines the entire user control program to find whether the search parameters are satisfied and, if the search parameters are satisfied, displaying on the screen the plurality of nodes in the network format in which a specific node satisfies the search parameters and, if the search parameters are not satisfied displaying information on the screen indicating the same.

12. An improved programmable controller as defined in claim 11, wherein the means for performing the search function further generate a cursor on the screen at the specific node satisfying the search parameters.

13. An improved programmable controller as defined in claim 12, wherein the means for performing the search function if the search parameters are satisfied further displays on the screen identifying data of the specific plurality of nodes in a network format in which the search parameters have been satisfied.

14. An improved programmable controller of the type having a mainframe including a central processing unit, associated electronics and memory for solving a user control program, an input/output system for communicating input data from external devices to the mainframe and for transferring output data from the mainframe to the external devices for control thereof in response to the control program, and a programming panel for programming, monitoring and displaying the user selected control program, wherein the improvement comprises:

(A) an improved mainframe having means for solving calculate functions in the user control program wherein at least some of the calculate functions have more than one discrete output designating information concerning the result of the calculate function; and

(B) An improved programming panel comprising;

(1) a screen for viewing at least a portion of the control program; and

(2) means for allowing the user to generate the control program in a network format, each network comprising up to I rows and J columns, where I and J are positive integers each greater than one, each network comprising up to I×

J nodes where the location of each node is N_ij, where i=1, 2, . . . I, j=1, 2, . . . J, and where each of at least some of these nodes are designatable by the user as representing an electrical circuit element that can reference other nodes, and having a power output status that is a function of the input power status to the node in combination with the conductivity status of the element, and wherein the calculate functions can be displayed in nodes on the screen.

15. An improved programmable controller as defined in claim 14, wherein the means for solving calculate functions includes means for solving the subtract function with three discrete outputs, a first of the outputs having a first state indicating when the minuend is less than or equal to the subtrahend and a second state indicating when the minuend is greater than the subtrahend, a second output having a first state indicating when the minuend is not equal to the subtrahend and a second state indicating when the minuend is equal to the subtrahend, and a third output having a first state indicating when the minuend is greater than or equal to the subtrahend and a second state when the minuend is less than the subtrahend.

16. An improved programmable controller as defined in claim 14, wherein the means for solving calculate functions includes means for solving the divide function with three discrete outputs, a first of the outputs having a first state indicating when the division to be performed is not possible and a second state indicating when the division to be performed is possible, a second output having a first state indicating when the divisor if multipled by a number equal to the total field of the answer is less than the dividend, and a second state indicating when the dividend is an overflow, and a third output having a first state indicating when the divisor is equal to zero and a second state indicating when the divisor is not equal to zero.

17. An improved programmable controller as defined in claim 14, 15, or 16 wherein the mainframe has means for allowing any or all calculate function discrete outputs to be referenced by electrical circuit elements in other nodes.

18. An improved programmable controller as defined in claim 14, 15, or 16 wherein the mainframe has means for allowing any or all calculate function discrete outputs to represent output data from the mainframe.