Programmable controller with I/O expansion module located in one of I/O module positions for communication with outside I/O modules

Claim 3

The method of claim 1, wherein the coupling of words of I/O status data to the I/O modules is modified upon an enabling of the I/O expansion module to execute the coupling of the multiword block of I/O status data.

Claim 4

The method of claim 1, wherein the second group of I/O modules includes I/O modules in a second equipment rack and also includes I/O modules outside of any equipment rack.

Claim 5

An I/O expansion module for connection to a backplane in a primary equipment rack that is adapted to hold an in-rack processor and a plurality of first tier I/O modules and for communication with one or more second tier I/O modules residing outside the primary equipment rack, the I/O expansion module comprising: backplane controller means for electronic communication with the in-rack processor through the backplane when the I/O expansion module is located in any one of a plurality of individually addressable I/O module positions corresponding to image table memory addresses existing within the in-rack processor prior to I/O expansion, the backplane controller means communicating during operation with the in-rack processor for transfer of bytes of parallel I/O status data through the rack backplane to the I/O expansion module residing at a single open of the addressable I/O module positions existing prior to I/O expansion as part of a routine in which modules in respective I/O module positions in the equipment rack are enabled for communication with the in-rack processor; a serial I/O port for communication with one or more second tier I/O modules located outside the equipment rack; serial channel controller means coupled to the serial I/O port, wherein the serial channel controller means includes a second image table for storing the bytes of I/O status data in locations associated with the one or more second tier I/O modules; means for transferring I/O status data between the backplane controller means and the second image table in the serial channel controller means; and wherein the serial channel controller means also includes means for controlling the serial communication of I/O status data between the second image table and the one or more second tier I/O modules.

Claim 6

An I/O expansion module for connection to a backplane in a primary equipment rack that is adapted to hold an in-rack processor and a plurality of first tier I/O modules and for communication with one or more second tier I/O modules residing outside the primary equipment rack, the I/O expansion module comprising: backplane controller means for electronic communication with the in-rack processor through the backplane when the I/O expansion module is located in any one of a plurality of individually addressable I/O module positions corresponding to image table memory addresses existing within the in-rack processor prior to I/O expansion, the backplane controller means communicating during operation with the in-rack processor for transfer of bytes of parallel I/O status data through the rack backplane to the I/O expansion module residing at a single open of the addressable I/O module positions existing prior to I/O expansion as part of a routine in which modules in respective I/O module positions in the equipment rack are enabled for communication with the in-rack processor; a serial I/O port for communication with one or more second tier I/O modules located outside the equipment rack; serial channel controller means coupled to the serial I/O port, wherein the serial channel controller means includes a second image table for storing the bytes of I/O status data in locations associated with the one or more second tier I/O modules; means for transferring I/O status data between the backplane controller means and the second image table in the serial channel controller means; and wherein the serial channel controller means also includes means for controlling the serial communication of I/O status data between the second image table and the one or more second tier I/O modules.

Claim 7

The I/O expansion module of claim 4, wherein the means for transferring I/O status data comprises: a common read/write memory; arbitration circuitry coupling the backplane controller means and the serial channel controller means for alternating access to the common read/write memory; and means in the backplane controller means and means in the serial channel controller means that are each in electronic communication with the arbitration circuitry and with the common read/write memory to transfer I/O status data between the backplane controller means and the image table in the serial channel controller means.

Claim 8

The I/O expansion module of claim 4, wherein the image table has a plurality of locations corresponding to respective second tier I/O modules; and wherein the means for controlling communication between the image table and the second tier I/O module couples I/O status data in serial data format for a plurality of second tier I/O modules.

Claim 9

The I/O expansion module of claim 4, wherein the means for controlling communication between the image table and the second tier I/O module couples I/O status data for a plurality of second tier I/O modules.

Claim 10

The improvement of claim 7, wherein the second tier I/O modules include I/O modules in another equipment rack and also include I/O modules outside of any equipment rack.

Claim 11

In a programmable controller of a type having a primary equipment rack for connection to a plurality of first tier I/O modules through a backplane and of a type having a processor module for connection to the backplane, wherein the processor module has a first I/O image table for storing discrete bytes of I/O status data and has a bulk storage area for storing a block to I/O status data, an improvement of an I/O expansion module for connection to the backplane and for connection to a plurality of second tier I/O modules residing outside the primary equipment rack, wherein the I/O expansion module comprises: backplane controller means for electronic communication with the processor module through the rack backplane when the I/O expansion module is located an any one of a plurality of individually addressable I/O module positions corresponding to respective addresses existing in the first image table prior to I/O expansion, the backplane controller means communicating during operation with the processor module for transfer of the block of I/O status data through the rack backplane as part of a routine in which the discrete bytes of I/O status data are transferred for other I/O modules in the primary equipment rack; a serial I/O port for communication with the second tier I/O modules located outside the primary equipment rack; serial channel controller means coupled to the serial I/O port, wherein the serial channel controller means includes a second image table for storing the block of I/O status data such that a byte of I/O status data is associated with the second tier I/O module; means for transferring the block of status data between the backplane controller means and the second image table in the serial channel controller means; and wherein the serial channel controller means also includes means for handling the I/O status data associated with the second tier I/O modules as serial data incorporated in messages that are coupled between the second image table and the second tier I/O modules to multiplex and d®multiplex the I/O status data; and wherein the I/O expansion module is located at a single one of the individually addressable I/O positions corresponding to a single respective first image table address existing prior to I/O expansion.

Claim 12

In a programmable controller of a type having a primary equipment rack for connection to a plurality of first tier I/O modules through a backplane and of a type having a processor module for connection to the backplane, wherein the processor module has a first I/O image table for storing discrete bytes of I/O status data and has a bulk storage area for storing a block to I/O status data, an improvement of an I/O expansion module for connection to the backplane and for connection to a plurality of second tier I/O modules residing outside the primary equipment rack, wherein the I/O expansion module comprises: backplane controller means for electronic communication with the processor module through the rack backplane when the I/O expansion module is located an any one of a plurality of individually addressable I/O module positions corresponding to respective addresses existing in the first image table prior to I/O expansion, the backplane controller means communicating during operation with the processor module for transfer of the block of I/O status data through the rack backplane as part of a routine in which the discrete bytes of I/O status data are transferred for other I/O modules in the primary equipment rack; a serial I/O port for communication with the second tier I/O modules located outside the primary equipment rack; serial channel controller means coupled to the serial I/O port, wherein the serial channel controller means includes a second image table for storing the block of I/O status data such that a byte of I/O status data is associated with the second tier I/O module; means for transferring the block of status data between the backplane controller means and the second image table in the serial channel controller means; and wherein the serial channel controller means also includes means for handling the I/O status data associated with the second tier I/O modules as serial data incorporated in messages that are coupled between the second image table and the second tier I/O modules to multiplex and d®multiplex the I/O status data; and wherein the I/O expansion module is located at a single one of the individually addressable I/O positions corresponding to a single respective first image table address existing prior to I/O expansion.

Claim 13

The improvement of claim 9, wherein the second tier I/O modules include I/O modules in another equipment rack and also includes I/O modules outside of any equipment rack.