Programmable controller with intelligent positioning I/O modules

• US 4,510,565 A
• Filed: 09/20/1982
• Issued: 04/09/1985
• Est. Priority Date: 09/20/1982
• Status: Expired due to Term

• Current Assignee: Allen-Bradley Company (Rockwell Automation, Inc.)
• Original Assignee: Allen-Bradley Company (Rockwell Automation, Inc.)
• Inventors: Dummermuth, Ernst
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US06/420,561
• Time in Patent Office: 932 Days
• Field of Search: 364/131, 364/132, 364/133, 364/134, 364/136, 364/140-147, 364/200, 364/900, 364/474, 364/475, 364/167-171, 364/174
• US Class Current: 700/7
• CPC Class Codes: G05B 19/4147 characterised by using a programmable interface controller [PIC]
• CPC Class Codes: G05B 2219/33129 Group spindles, axis into motion groups, nc channel structure
• CPC Class Codes: G05B 2219/34208 Motion controller
• CPC Class Codes: G05B 2219/34286 Intelligent positioning I-O
• CPC Class Codes: G05B 2219/34396 Control different groups of functions, commands simultaneously, synchronized
• CPC Class Codes: G05B 2219/34448 Integrated servo control circuit fixed to housing, remote from cpu
• CPC Class Codes: G05B 2219/41275 Two axis, x y motors controlled simultaneous, no contouring, quick move at 45-degrees
• CPC Class Codes: G05B 2219/43009 Acceleration deceleration for each block of data, segment
• CPC Class Codes: G05B 2219/43041 Prediction, look ahead deceleration control, calculate start deceleration

Abstract

A programmable controller for closed-loop positioning control has a main processor unit, and an I/O interface rack in which a master I/O positioning module and three satellite I/O modules are mounted and connected to servomechanisms to control motion along three axes of a controlled machine. Move data is transmitted from the main processor unit to the master I/O positioning module in data blocks, with the number of transmissions varying, depending upon a mode of axis coupling that is used in controlling the particular machine. The master I/O positioning module converts move data from a user program format to a binary format and transfers it to the satellite I/O modules, each of which performs closed-loop positioning control of a respective axis of motion. The processor on each satellite I/O module also determines a position prior to the end of each move to apply a user-programmed deceleration when needed to blend moves having different velocities.

Claims

1. An electrical controller for controlling machine motion through a plurality of electromechanical I/O positioning devices, the controller comprising:

a plurality of I/O circuits each connectable to a respective I/O positioning device to generate output drive signals thereto in response to move data, and to transmit a move request signal when move data is needed;

main processing means for storing and transmitting (i) user-selectable parameter data, including a user-selected mode of axis coupling designating coupled I/O circuits and independent I/O circuits and (ii) user-selectable move data, including coupled move data applicable to coupled I/O circuits and independent move data applicable to independent I/O circuits; and

master I/O processing means coupled to the main processing means for receiving the parameter data and the move data, and coupled to the I/O circuits for receiving move request slgnals, the master I/O processing means being responsive to the parameter data from the main processing means and to move request signals from any coupled I/O circuits to receive coupled move data in a single transmission from the main processing means and to distribute portions of the coupled move data to each of the coupled I/O circuits, the master I/O processing means also being responsive to the parameter data from the main processing means and to move request signals from any independent I/O circuits to receive independent move data in a separate transmission from the main processing means and to couple the independent move data to the independent I/O circuit associated with that separate transmission.

2. The controller of claim 1, wherein two coupled I/O circuits and one independent I/O circuit are controlled, wherein move data is coupled in two blocks from the main processing means to the master I/O processing means, one block of move data including coupled move data for the two coupled I/O circuits and the other block of move data including independent move data for the independent I/O circuit, and wherein the master I/O processing means distributes portions of the coupled move data to each of the coupled I/O circuits and distributes the independent move data to the independent I/O circuit.

3. The controller of claim 1, wherein the main processing means transmits a block of coupled move data that includes data for a plurality of coupled moves that are distributed by the master I/O positioning means to any coupled I/O circuits, and wherein the main processing means transmits a block of independent move data that includes data for a plurality of independent moves that are coupled by the master I/O processing means to any independent I/O circuit.

4. The controller of claim 3, wherein the block of coupled move data and the block of independent move data each contain a control word directing a plurality of moves to be executed in a continuous sequence, and wherein the master I/O processing means and the I/O circuits are responsive to the control words to execute the move data in a continuous sequence.

5. The controller of claim 1, wherein the main processing means also stores a motion control block of data representing manual input motion commands and also stores a pointer to the motion control block as part of the parameter data, wherein the master I/O processing means, in absence of move request signals from the I/O circuits, gives priority to the inclusion of the pointer to the motion control block of data within a status block of data that is returned to the main processing means, wherein the main processing means transmits the motion control block of data in response to receiving its corresponding pointer, and wherein the master I/O processing means is responsive to the receipt of the motion control block of data to couple manual input motion command data to the I/O circuits which execute the manual input motion commands.

6. The controller of claim 1, wherein the master I/O processing means is coupled to the main processing means through an I/O interconnect cable, and wherein the master I/O processing means and the I/O circuits are formed in respective circuit modules that are mounted in a rack and electrically connected through a backplane circuit board.

7. The controller of claim 1, wherein the I/O circuits read position input signals from the I/O positioning devices and generate output drive signals thereto that are responsive to the difference between a command position determined from the move data and an actual position determined from the position input signals, thereby providing closed-loop positioning control of the I/O positioning devices.

8. An electrical controller for controlling machine motion through a plurality of electromechanical I/O positioning devices, the controller comprising:

a plurality of satellite I/O modules each connectable to a respective I/O positioning device to generate output drive signals thereto in response to move data, wherein each satellite I/O module requests move data, when needed, by transmitting a move request signal;

a main processing unit that transmits parameter data and move data and receives status data during I/O operations, the main processing unit including

memory means for storing the parameter data, which includes data indicating the number of satellite I/O modules, which includes data that selects one of the two modes of axis coupling, at least two of the satellite I/O modules being coupled for directing coordinated motion along respective axes in the first mode of axis coupling, and one or more independent satellite I/O modules directing motion independently along respective axes in the second mode of axis coupling, the parameter data also including data pointers to the locations of the move data,

the memory means also storing move data as coupled moves applicable to coupled satellite I/O modules and as individual moves applicable to independent satellite I/O modules, and

processing means coupled to the memory means for transmitting the parameter data and for receiving status data including a data pointer, and in response to the status data, for transmitting move data in one transmission for each plurality of coupled satellite I/O modules and for transmitting move data in a separate transmission for each independent satellite I/O module; and

master I/O processing means electrically coupled to the processing means in the main processing unit to receive the parameter data and electrically coupled to the satellite I/O modules to receive move request signals, the master I/O processing means including

means responsive to move request signals from any of the coupled I/O satellite modules and from any independent satellite I/O module for transmitting status data to the main processing means that includes a pointer to the move data for the requesting satellite I/O module, and

means for receiving the move data in response to the transmission of the status data, and in response to the parameter data received previously, distributing the move data received in coupled moves to the respective coupled satellite I/O modules and distributing the move data in independent moves to its associated independent satellite I/O module.

9. The controller of claim 8, wherein one of the modes of axis coupling provides for two coupled satellite I/O modules and one independent satellite I/O module, wherein the move data is stored in two blocks that are coupled through the processing means in the main processing unit to the master I/O processing means, one block of move data including coupled move data for the two coupled satellite I/O modules, and the other block of move data including independent move data for the independent satellite I/O modules, and wherein the master I/O processing means distributes portions of the coupled move data to each of the coupled satellite I/O modules and distributes the independent move data to the independent satellite I/O module.

10. The controller of claim 8, wherein the processing means in the main processor unit transmits a block of coupled move data that includes data for a plurality of coupled moves that are transmitted by the master I/O processing means to any coupled satellite I/O modules, and wherein the processing means in the main processor unit transmits a block of independent move data that includes a plurality of independent moves that are transmitted by the master I/O processing means to any independent satellite I/O modules.

11. The controller of claim 10, wherein any block of coupled move data and any block of independent move data each contain a control word for directing the execution of the moves therein in a continuous sequence, and wherein the master I/O processing means and the satellite I/O modules are responsive to the control words to execute the moves in a continuous sequence.

12. The controller of claim 8, wherein the memory means in the main processing unit also stores a motion control block of data representing manual input motion commands and also stores a pointer to the motion control block of data as part of the parameter data, wherein the master I/O processing means, in the absence of move request signals from the satellite I/O modules, gives priority to the inclusion of the pointer to the motion control block of data within a status block of data that is returned to the processing means in the main processor unit, wherein the processing means in the main processor unit couples the motion control block of data from its associated memory means to the master I/O processing means in response to receiving the pointer for the motion control block of data, wherein the master I/O processing means is responsive to the receipt of the motion control block of data to couple motion command data to the satellite I/O modules, and wherein the satellite I/O modules are responsive to the motion command data to execute the manual input motion commands.

13. The controller of claim 8, wherein the master I/O processing means is coupled to the main processing unit through an I/O interconnect cable, and wherein the master I/O processing means is formed as a master I/O positioning module, is mounted in a rack with the satellite I/O modules, and is electrically connected to the satellite I/O modules through a backplane circuit board.

14. The controller of claim 8, wherein the satellite I/O modules read position input signals from the I/O positioning devices and generate output drive signals thereto that are responsive to the difference between a command position determined from the move command data and an actual position determined from the position input signals, thereby providing closed-loop positioning control of the I/O positioning devices.

15. A programmable controller for closed-loop positioning control of machine motion through an I/O positioning device, which moves in response to velocity signals and which generates position feedback signals, the controller comprising:

a main processor that stores and transmits userprogrammable move data including a programmed position, a programmed velocity and a programmed deceleration for each of a plurality of successive moves; and

a satellite I/O module coupled to the main processor, and coupled to the I/O positioning device to read the feedback signals therefrom and to generate velocity output signals thereto, the satellite I/O module including

first memory means for storing move data received from the main processor,

an axis processor coupled to the main processor to receive the move data for successive moves, coupled to the first memory means to transfer the move data thereto, and coupled to the I/O positioning device to receive the position feedback signals and to transmit the velocity output signals, and

second memory means for storing machine instructions for the axis processor,

wherein the axis processor is operable to compute the actual velocity for the present move and to detect a programmed velocity for a next move that is less than the actual velocity of the present move, and

wherein the axis processor is further operable to detect a point of deceleration before reaching the end of the present move and to then apply the programmed deceleration to the actual velocity, so that the next move can be initiated at its programmed velocity.

16. An intelligent positioning I/O module for real-time closed-loop positioning control of one axis of machine motion, the I/O module being insertable into a rack structure, the I/O module being connectable for communication with a programmable controller main processor, and the I/O module being connectable to a servomechanism controlling motion along the axis, the I/O module comprising:

memory means for receiving user-selected move data for a present move and user-selected data for a next move from the programmable controller main processor, the user-selected move data for each move including a programmed destination, a programmed velocity and a programmed deceleration;

input circuit means connectable to a position sensing portion of the servomechanism to receive position feedback signals and to convert such signals to position feedback data;

output circuit means connectable to drive a servo motor portion of the servomechanism by coupling servo velocity output signals thereto, the output circuit means converting servo velocity output data to the servo velocity output signals that are coupled to the servo motor portion;

programmed axis processor means coupled to the memory means to obtain the user-selected move data therefrom, coupled to the input circuit means to receive position feedback data and coupled to the output circuit means to generate servo velocity output data thereto to control axis motion;

wherein the programmed axis processor means is operable to compute servo output velocity data for the present move and to detect a programmed velocity for the next move that is less than the servo output velocity of the present move; and

wherein the programmed axis processor means is further operable to detect a point of deceleration before reaching the end of the present move to then apply the programmed deceleration to reduce the servo output velocity data before it is coupled to the output circuit means, so that the next move can be initiated at its programmed velocity.

17. An intelligent positioning I/O module for real-time closed-loop positioning control of one axis of machine motion, the I/O module being insertable into a rack structure, the I/O module being connectable for communication with a programmable controller main processor, and the I/O module being connectable to a servomechanism controlling motion along the axis, the I/O module comprising:

first memory means for receiving user-selected move data for a present move and a next move from the programmable controller main processor, the user-selected move data for each move including a programmed destination, a programmed velocity and a programmed acceleration and deceleration;

input circuit means connectable to a position sensing portion of the servomechanism to receive position feedback signals and to convert such signals to position feedback data;

output circuit means connectable to drive a servo motor portion of the servomechanism by coupling servo velocity output signals thereto, the output circuit means converting servo velocity output data to the servo velocity output signals that are coupled to the servo motor portion;

second memory means for storing a first sequence of axis processor instructions to generate servo velocity output data to the output circuit means to drive the servomechanism in response to the difference between an accumulation of command position increments, and an accumulation of position feedback data received from the input circuit means, the second memory means also storing a second sequence of axis processor instructions to calculate command position increments for the present move based on the programmed destination to be reached at the end of the present move, the accumulation of position feedback data, the programmed velocity for the next move, and the programmed acceleration or deceleration;

timing means for providing a periodic signal on a preselected time base; and

an axis processor coupled to the timing means, coupled to the first and second memory means and coupled to the input circuit means and output circuit means, the axis processor being responsive to each periodic signal from the timing means to read and execute the first and second sequences of axis processor instructions to generate servo output velocity signals to the servomechanism through the output circuit means and to read position feedback signals from the servomechanism through the input circuit means to provide real-time closed-loop positioning control on the preselected time base, such control including the application of the programmed acceleration or deceleration to change from the velocity of the present move to the programmed velocity of the next move.

18. A programmable controller for controlling machine motion through a plurality of electromechanical I/O positioning devices, the controller comprising:

a plurality of I/O circuits each connectable to a respective I/O positioning device to generate output drive signals thereto in response to move data, and to transmit a move request signal when data is needed;

main processing means for storing and transmitting (i) user-selected parameter data, which includes a pointer to a motion control block of data, (ii) the motion control block of data, which represents manual input motion commands, and (iii) user-selected move data;

master I/O processing means coupled to the main processing means for receiving the parameter data and the move data and for transmitting a status block of data, and coupled to the I/O circuits for receiving move request signals, the master I/O processing means transmitting the status block of data with a pointer to the motion control block of data in the absence of move request signals from the I/O circuits;

wherein the main processing means transmits the motion control block of data in response to receiving its corresponding pointer; and

wherein the master I/O processing means is responsive to the receipt of the motion control block of data to coupled manual input motion commands to the I/O circuits, which execute these commands.