The SPT Final Finish Line Control System has been developed in the C programming language on an IBM Risc System/6000 (RS/6000) running IBM's variant of unix known as AIX. The system maintains data in flat files with BTREE indexes on important file/fields for quick access. It was designed to capture results from tyre testing equipment, compare those results with minimum acceptable values. Those tyres that meet the specified requirements are graded and shipped to the warehouse, those that fail are rejected from the line. The details of all tyres is sent to the AS/400 for statistical analysis and for inter- divisional accounting.
The computer control system is not one program, but is a number programs that communicate through a mechanism known as shared memory. Under this scheme, the programs that interact with the devices on the line place data in memory that is available to the Master Control Program (mcp). Mcp regularly examines this shared memory and gathers the required data and supplies commands for these line controlling programs.
The line control programs (barcode, plc, balance, scale, runout, circle, stacker & as400) are slaves of mcp, they make no decisions regarding the passage of tyres through the line, they understand the protocol of the devices that they control and they keep these protocol details from mcp. This design allows for the addition or replacement of external devices with a minimum of disruption to mcp. This replacement with minimum disruption has already been seen with the replacement of the Yokogowa stacker and the addition of the AS/400 communication program.
I was responsible for the initial design of the RS/6000 programs, the management of the project which covered the my programing and testing of the RS/6000, management of the programmer responsible for the PC to interface the RS/6000 to the PLC that was controlling the line and the liason with the plant engineer responsible for the wiring and programming of the PLC. I was also responsible for the development of system administration proceedures for the RS/6000 until the hand over to the MIS department. Finally, I was the involved with the MIS department in the transfer of data from the RS/6000 to the AS/400.