Programmable logic controller protocol converter

A non-transitory computer-readable storage medium containing a program configured to perform a method for exposing data from a programmable logic controller (PLC) device, the program including instructions for performing an operation, comprising:

• accessing a configuration file identifying a plurality of PLC addresses to expose;
• initializing a shared memory array, wherein the shared memory array includes a plurality of elements each used to store data obtained from the PLC device;
• invoking a first thread, wherein the first thread is configured to, repeatedly:
• transmit a request for one of the identified PLC addresses, wherein the request is configured according to a first communication protocol, wherein the first protocol comprises a Non-Intelligent Terminal Protocol (NITP), and
• store a data value returned by the PLC device in response to the request in one of the elements of the shared memory array;
• and
• invoking a second thread, wherein the second thread is configured to:
• receive a request, communicated according to a second communication protocol, for one or more of the data values stored in the shared memory array,
• retrieve the requested one or more data values, and
• return the requested data values in a format consistent with the second communication protocol.

A system, comprising:

• a processor;
• and
• a memory containing a program configured to perform an operation for obtaining data values from a programmable logic controller (PLC) device, the operation comprising:
• parsing a configuration file identifying a plurality of PLC addresses to expose;
• initializing a shared memory array, wherein the shared memory array includes a plurality of elements each used to store data obtained from the PLC device;
• invoking a first thread, wherein the first thread is configured to, repeatedly:
• transmit a request for one of the PLC addresses, wherein the request is configured according to a first communication protocol, wherein the first protocol comprises a Non-Intelligent Terminal Protocol (NITP), and
• store a data value returned by the PLC device in response to the request in one of the elements of the shared memory array;
• and
• invoking a second thread, wherein the second thread is configured to:
• receive a request, communicated according to a second communication protocol, for one or more of the data values stored in the shared memory array,
• retrieve the requested one or more data values, and
• return the requested data values in a format consistent with the second communication protocol.