Programmable controller for executing block transfer with remote I/O interface racks

A remote I/O interface for a digital controller of the type having a main processor for executing a control program to examine and determine I/O status data, having memory means associated with the main processor for storing a first control word that defines a direction of I/O transfer and the size of a multiword block of I/O status data stored in said memory means and having a plurality of I/O interface racks each adapted to hold a plurality of I/O modules that are responsive to I/O status data to sense and control the status of I/O devices connected to a controlled system, at least one of the I/O interface racks holding a high density I/O module that stores a second control word which confirms the direction of I/O transfer and the size of the multiword block of I/O status data to be coupled to said memory means, wherein the remote I/O interface comprises:

• a serial data link extending from a proximate end near the main processor to a plurality of remote ends at respective I/O interface racks;
• adapter circuit means disposed in the I/O interface rack with the high density I/O module, coupled to a respective remote end of the serial data link and adapted to be coupled to other I/O modules disposed in the I/O interface rack with the high density I/O module, for executing an I/O scan sequence in which individual words of I/O status data are coupled to and from the I/O modules, except for the high density I/O module to which the first control word is coupled, and in which a block transfer request signal and the second control word are coupled from the high density I/O module to the serial data link in response to the coupling of the first control word, the adapter circuit means includes means thereafter responsive to a command message received through the serial data link for coupling a reply message to the serial data link, wherein a block of output status data is received in the command message and is coupled to the high density I/O module, or wherein a block of input status data is coupled from the high density module and incorporated in the reply message, according to the direction of I/O transfer determined by the first and second control words;
• and
• scanner circuit means, electrically connected to the main processor and to the memory means associated with the main processor, for coupling blocks of I/O status data to and from said memory means, the scanner circuit means also being electrically to the proximate end of the serial data link, for executing an I/O scan sequence of the I/O interface racks in which I/O status data is coupled through the serial data link, the scanner circuit means being responsive to the receipt of the block transfer request signal from the adapter circuit means to couple the second control word to the main processor and to couple a multiword block of I/O status data between the memory means associated with the main processor and the serial data link, the scanner circuit means coupling the multiword block of I/O status data to the serial data link in the command message or receiving the block of I/O status data in a responsive reply message from the adapter circuit means, according to the direction of I/O transfer determined by the first and second control words.

A remote I/O interface for a digital controller of the type having a main processor and having memory means associated with the main processor for storing a first control word and a multiword block of I/O status data, the controller also having a plurality at I/O interface racks each adapted to hold a plurality of I/O modules that are responsive to I/O status data to sense and control the status of I/O devices connected to a controlled system, at least one of the I/O interface racks holding a high density I/O module which stores a second control word to acknowledge the first control word and which is operable to couple the multiword block of I/O status data to or from a group of I/O devices, wherein the remote I/O interface comprises:

• a serial data link extending from a proximate end near the main processor to a plurality of remote ends at respective I/O interface racks;
• a scanner circuit having a scanner data link interface circuit electrically connected to the proximate end of the serial data link and having scanner processor means electrically connected to the scanner data link interface circuit and cooperable therewith for periodically coupling the first control word from the memory means associated with the main processor to the serial data link together with a block transfer "not busy" signal and for receiving in response a block transfer request signal, the second control word and address signals associated with the high density I/O module;
• the scanner processor means also includes means cooperable with the scanner data link interface circuit and responsive to the block transfer request signal for transmitting a block transfer command message over the serial data link and for receiving in response a block transfer reply message;
• and
• the scanner processor means also includes means coupled to the memory means that stores the multiword block of I/O status data and being cooperable with the scanner data link interface circuit for coupling the multiword block of I/O status data in an output direction from the memory means to the serial data link as part of the block transfer command message or for coupling the multiword block of I/O status data received as part of the block transfer reply message in an input direction to the memory means, according to the output direction or input direction of the I/O status data coupling;
• and
• an adapter circuit having processor means electrically connected to the high density I/O module for periodically coupling address signals to the high density I/O module and detecting a responsive block transfer request signal that is then associated with such address signals,
• the adapter circuit also having an adapter data link interface circuit electrically connected between the adapter processor means and the serial data link, the adapter processor means and the adapter serial data link interface circuit being cooperable for coupling the block transfer request signal, the address signals associated therewith and the second control word to the serial data link in response to the block transfer "not busy" signal received through the serial data link,
• the adapter processor means and the adapter data link interface circuit being further responsive to the block transfer command message received through the serial data link to transmit the block transfer reply message and couple the multiword block of I/O status data to or from the high density I/O module, according to the output or input direction of I/O status data coupling.

A remote I/O interface for interconnection between a main processor and a plurality of I/O modules that includes a plurality of single-word capacity I/O modules and a multiword capacity I/O module, the I/O modules being responsive to I/O status data to sense and control the status of I/O devices connected to a controlled machine, the main processor executing a control program to examine and determine I/O status data, the main processor also being operable to execute a local I/O scan sequence to sequentially couple words of I/O status data to or from the single-word capacity I/O modules, and the main processor also being operable to modify the local I/O scan to couple a multiword block of I/O status data to or from the multiword capacity I/O module, the remote I/O interface comprising:

• a scanner circuit having first memory means adapted to be connected to the main processor for storing the words of I/O status data coupled during the local I/O scan sequence, the scanner circuit having second memory means adapted to be connected to the main processor for storing the multiword block of I/O status data that is coupled when the main processor modifies the local I/O scan sequence, the scanner circuit also having a serial data link interface circuit and the scanner circuit having scanner processor means for coupling first and second pairs of serial data messages through the serial data link interface circuit, one of the first pair of serial data messages including words of I/O status data associated with the single-word capacity I/O modules, and one of the second pair of serial data messages including a multiword block of I/O status data associated with the multiword capacity I/O module;
• an adapter circuit having adapter memory means for storing words of I/O status data associated with the single word capacity I/O modules, having an adapter data link interface circuit, and having adapter processor means coupled to the adapter data link interface circuit to receive the first and second pairs of serial data messages, the adapter processor means being connected to the adapter memory means and being adapted to be connected to the single-word capacity I/O modules and to the multiword capacity I/O module, the adapter processor means being operable to execute an adapter I/O scan sequence to sequentially couple words of I/O status data between the adapter memory means and respective single-word capacity I/O modules, and the adapter processor means being operable to modify its local I/O scan sequence to sequentially couple words of I/O status between the adapter data link interface circuit and the multiword capacity I/O module;
• and
• a serial data link for connecting the scanner data link interface circuit to the adapter data link interface circuit to carry the first and second pairs of serial data messages.