ABSTRACT
The software that is required for direct numerical control (ONC) operations is located primarily on a host computer and is able to provide ONC support to a number of independent work stations. This software operates on the host computer because this is the focal point for each of the individual numerical control systems. If the machine tool control system is capable of handling the necessary bidirectional communications with the host then no additional interface equipment will be required. Otherwise, the host must communicate directly with an additional shop floor processor that passes information back and forth from the machine tool control through the control system's serial interfaces (which are usually used for the tape reader and tape punch). In either situation, additional interfaces also may be required to provide automatic remote control of the control system's functions. The hardware and software must be available to allow the shop floor processor to push the buttons on the control system as it simulates the actions of the manual operation, or else a machine operator must be available to initiate and supervise the activities of the system. Manual operations may be quite acceptable if the major ONC activities consist of occasionally down loading part programs and up loading status information. However, if an operator is not always present or if portions of the system's operations such as on-machine gaging and adjustments require automation then the interfaces become more complex.
