Programmable logic controller method, system and apparatus

A method for debugging a program in real time and while said program is executed by a programmable logic controller, said method comprising the steps of:

• displaying a section of said program indicated by a user to be debugged;
• saving original compiled code of said program;
• compiling said section of said program to be debugged in another section of memory;
• jumping to said another section of said memory during execution of said program when an instruction indicated to be debugged is to be executed;
• and
• capturing a status of said instruction as it is executed, wherein said program is debugged in real time and while said program is executed by said programmable logic controller.

An apparatus that debugs a program in real time and while said program is executed by a programmable logic controller, said method comprising the steps of:

• an area of memory for saving original compiled code of said program;
• another area of memory for storing a compiled section of said program to be debugged;
• a branch that causes execution of said instruction to jump from said original compiled code to said another section of said memory during execution of said program when an instruction indicated to be debugged is to be executed;
• and
• a circuit for capturing a status of said instruction as it is executed, wherein said program is debugged in real time and while said program is executed by said programmable logic controller.

An apparatus for high speed discrete output, said apparatus comprising:

• a first optical transistor that, when turned on, connects a gate of an output transistor to a supply voltage such that the output transistor is turned OFF;
• a second optical transistor that, when turned on, connects said gate of said output transistor to said supply, turning the output ON and driving the external load;
• and
• logic that drives said first and second optical transistors as a complementary pair, so that for an output OFF state said first optical transistor is conducting and said second optical transistor is not, and in an output ON state said second optical transistor is conducting and said first optical transistor is not.

A method for high speed discrete output, said method comprising the steps of:

• driving first and second optical transistors as a complementary pair so that for an output OFF state said first optical transistor is conducting and said second optical transistor is not, and in an output ON state said second optical transistor is conducting and said first optical transistor is not.;
• on transitions between output OFF and output ON, turning on said second optical transistor relatively quickly, thereby providing a path to discharge the a gate capacitance of a gate coupled to said complementary pair and providing the low impedance path required for a quick turn off of said first optical transistor;
• and
• on an ON to OFF transition, causing said first optical transistor to quickly pulls said gate high and provides a low impedance path for a quick turn off of said second optical transistor.

A method for supporting customized function calls in a programmable logic controller having a predetermined set of function calls, said method comprising the steps of:

• creating a customized function call for directing said programmable logic controller;
• downloading said customized function call to said programmable logic controller;
• and
• storing said customized function call as part of said predetermined set of function calls.