ISO/EIA Code Converting Method

a. Field of the Invention

This invention relates to an ISO/EIA code conversion method and, more particularly, to an ISO/EIA code conversion method in an NC data input/output unit capable of using an ISO code and an EIA code.

b. Description of the Related Art

In an automatic programming apparatus which automatically creates NC data, the NC data are created in either an ISO code or EIA code system and stored on an external storage medium such as a hard disk. At the time of use, the desired NC data are read out of the external storage medium to perform NC control.

Conventionally, the NC data created by such an automatic programming apparatus are input to or output from the external storage medium through any of the methods (1)-(3) described below.

(1) The code system of the NC data to be input is designated and then only the NC data of the designated code system are input to the external storage medium. At the time of output, the NC data of the input code system are output as is. For example, since an ISO code is an eight-bit code of even parity and an EIA code is an eight-bit code of odd parity, the code system of the input NC data is identified by the parity. The identified code system and a code system designated in advance are compared, only the NC data of the designated code system are stored on the external storage medium, and these data are output in response to a request.

(2) The code system of the NC data to be input are discriminated automatically, only data such as character or numeral data in which both the ISO and EIA codes are used while having the same meaning are converted into an internal code and stored, whereas data (referred to as a characteristic code) in which the ISO and EIA codes are used while having their own meanings, and which include undefined codes, are neglected without being converted into an internal code. At the time of output, the data converted into the internal code are output upon being converted into data of the code system designated at output time.

(3) The characteristic code neglected and not converted in method (2) is registered separately, and if the code system of the data output in (2) and the registered code system are the same, the data are output.

However, with the input/output processing of NC data in method (1), a problem encountered is that the method cannot be used in a case where the input code system and output code system differ. With the input/output processing of NC data in method (2), the characteristic code is neglected without relation to the input code system and output code system. Therefore, all of the data at the time of input cannot be stored in the external storage medium. With the input/output processing of NC data in method (3), the characteristic code must be separately registered and the registration operation is very troublesome.

Accordingly, an object of the present invention is to provide an ISO/EIA code conversion method in which storage is possible irrespective of the code system, input data can be output as is in a case where the input code system and output code system are the same, and an undefined code can be neglected and output in a designated code system in a case where the code systems differ.

In an ISO/EIA code conversion method according to the invention, there are provided a first conversion table for converting an ISO code and an EIA code into an internal code, and a second table for converting the internal code into an ISO code and EIA code. Characters and numerals in which the ISO code and EIA code are both employed are converted into the same internal code using the first conversion table, and characters and numerals in which the ISO code and EIA code are not both employed are converted into respective separate internal codes and stored. At the time of output, an output code system of the ISO code and EIA code for the output is designated, the internal code is output upon being converted into the designated code system by using the second conversion table, and the undefined codes are not output in the designated code system.

FIG. 1 is a block diagram of a system for practicing the method of the invention;

FIG. 2 is an explanatory chart for describing conversion of ISO/EIA codes into internal codes;

FIG. 3 is a flowchart of input conversion processing in the present invention; and

FIG. 4 is a flowchart of output conversion processing in the present invention.

FIG. 1 is a block diagram of a system (program file system) for practicing the present invention.

Numeral 1 denotes a processor and numeral 2 denotes a ROM storing a control program, a conversion table EIT for converting an eight-bit ISO or EIA code into an internal code, a conversion table ICT for converting an internal code into an ISO code, and a conversion table ECT for converting an internal code into an EIA code. Numeral 3 denotes a RAM for storing the results of processing and the like, 4 denotes an interface (e.g., a serial I/F conforming to RS-232-C) for a bit-serial data exchange with a host (automatic programming apparatus) or the like, 5 denotes an operator's panel, 6 denotes a display unit, (CRT), 7 denotes a floppy disk controller (FDC), 8 denotes a floppy disk drive (FDD), and FD1, FD2 denotes floppy disks. An ISO/EIA setting switch CSW is disposed on the operator's panel 5.

The conversion table EIT is for converting an eight-bit code, namely an ISO code (eight-bit even parity) and an EIA code (eight-bit odd parity) into respective internal codes. Characters, numerals and symbols sharing ISO and EIA codes are converted into the same internal code, and code unique to ISO and EIA codes which include undefined codes are converted into respective separate internal codes. FIG. 2 is an explanatory view for describing conversion of an ISO/EIA code into respective internal codes by the conversion table EIT. Numeral 11 denotes a group of NC data (the area in the circle indicated by the solid line) in which an ISO code has been converted into an internal code. Numeral 12 denotes a group of NC data (the area in the circle indicated by the broken line) in which an EIA code has been converted into an internal code. MDT represents a portion of the NC data in which characters, numerals and the like where the ISO and EIA codes both have the same meaning, thus they are converted into the same internal codes. SDT represents a portion of NC data in which special symbols, undefined codes and the like where only the ISO codes with a specific meaning are converted into internal codes. and EDT represents a portion of NC data in which special symbols, undefined codes and the like where only EIA codes of with a specific meaning are converted into internal codes.

The conversion table ICT is for converting an internal code into an ISO code. Internal codes (MDT, SDT in FIG. 2) corresponding to characters, numerals and symbols (defined codes) used in an ISO code system are converted into a predetermined ISO code, and internal codes (EDT in FIG. 2) corresponding to symbols (undefined codes) not used in an ISO code system are all converted into the same special code.

The conversion table ECT is for converting an internal code into an EIA code. Internal codes (MDT, EDT in FIG. 2) corresponding to characters, numerals and symbols (defined codes) used in an EIA code system are converted into a predetermined EIA code, and internal codes (SDT in FIG. 2) corresponding to symbols (undefined codes) not used in an EIA code system are all converted into the same special code.

FIG. 3 is a flowchart of input conversion processing according to the present invention. Input conversion processing for storing NC data, which is received from the host, on a floppy disk will now be described in accordance with the flowchart illustrated in FIG. 3.

First, when NC data arrive from the host via the serial interface 4, the processor 1 reads one character (code) of the NC data (step 101).

Next, it is determined whether the code read is a code indicating the end of the NC data (step 102). If the code read is an end code, an internal code indicative of end is stored on the floppy disk FD1 and input processing is terminated.

If the code read is not an end code, on the other hand, the code read is converted into a predetermined internal code (step 103) using the conversion table EIT and is then stored on the floppy disk FD1 (step 104). The next character is then read and processing from step 102 onward is repeated. More specifically, in the input conversion processing, the input code is converted into an internal code (see FIG. 2) using the conversion table EIT irrespective of whether the NC data is an ISO code or EIA code.

FIG. 4 is a flowchart of output conversion processing according to the present invention. Output conversion processing converts an internal code stored on a floppy disk into NC data of a predetermined code system and then outputting the same will now be described in accordance with the flowchart illustrated in FIG. 4.

First, the operator sets the output code system before the conversion is made. That is, by operating the ISO/EIA setting switch CSW on the operator's panel 5, a selection is made indicating whether the conversion is to be made to the ISO code or EIA code.

Thereafter, when an NC program number is designated and output conversion processing is started, the processor 1 reads one character (code) of the designated NC program from the floppy disk FD1 (step 201), checks to see whether the code indicates the end of the NC data (step 202). If the code indicates end of the NC data, the output conversion processing is terminated (step 202).

If the code does not indicate the end of the NC data, the processor 1 determines whether the code system selected by the ISO/EIA setting switch CSW is an ISO code or EIA code (step 203). If the code system selected is the ISO code, the internal code is converted into the ISO code using, the ion table ICT (step 204). If the code system selected is the EIA code, the internal code is converted into the EIA code using the conversion table ECT (step 205). It should be noted that the internal code EDT (see FIG. 2) is converted into a special code if the code system selected by the switch CSW is an ISO code system and that the internal code SDT is converted into a special code if the code system selected by the switch CSW is an EIA code.

Next, the processor 1 determines whether the result of conversion is a special code (step 206). If the result is a special code, no output is made and one character of the next internal code data is read out of the floppy disk FD1 (step 207) and processing beginning with step 202 is repeated.

If the result of conversion is not a special code, the code obtained by conversion is output and, for example, transferred to the host (step 208) via the serial interface 4. Likewise one character of the next internal code data is read out of the floppy disk FD1 (step 207), and processing from step 202 onward is repeated.

Since the present invention is constructed as described above, input data can be output as is, inclusive of characteristic codes, in a case where the input code system and output code system are the same. If the input code and output code differ, a code (characteristic code) not used in the output code system can be ignored, while outputting the input data which are convertable into the output code system.

The many features and advantages of the invention are apparent from the detailed specification and thus it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to as falling within the scope of the invention.