FP_ASCII_TO_HEX

ASCII -> HEX conversion

This FP instruction converts the hexadecimal ASCII HEX codes at s_Start to hexadecimal characters if the trigger EN is TRUE. n_Chars specifies the number of bytes to be converted.The result is stored in d.

ASCII code requires 8 bits (1 byte) to express one hexadecimal character.Upon conversion, the data length will thus be half the length of the ASCII code source data.

Parameters

Input

s_Start (WORD, INT, UINT): Starting address
n_Chars (INT, DINT, UINT, UDINT): Number of bytes

Output

d (WORD, DWORD): Converted bytes

Remarks

Two characters of ASCII code are converted into two one-byte numerical digits. In this process, higher-level characters and lower-level characters are exchanged. Four characters are converted as one segment of data.

ASCII HEX codes to express hexadecimal characters:

Hexadecimal character	ASCII HEX code
0123456789ABCDEF	16#3016#31 16#32 16#33 16#34 16#35 16#36 16#37 16#38 16#39 16#41 16#42 16#43 16#44 16#45 16#46

Error flags

sys_bIsOperationErrorHold (turns to TRUE and remains TRUE)

if the area specified using the index modifier exceeds the limit.
if the number of bytes specified by n_Chars is greater than the area specified by s_Start
if the conversion result is greater than the data area specified by d
if n_Chars = 0
if ASCII characters other than 0–F are specified

sys_bIsOperationErrorNonHold (turns to TRUE for one scan)

if the area specified using the index modifier exceeds the limit.
if the number of bytes specified by n_Chars is greater than the area specified by s_Start
if the conversion result is greater than the data area specified by d
if n_Chars = 0
if ASCII characters other than 0–F are specified

Example Signed/unsigned 16-bit data:

	Offset	ASCII codes	Hex. equivalent			Offset	Converted hex. characters
s1_Start	0	16#4241	BA	Þ	d	0	16#CDAB
s1_Start	1	16#4443	DC			1
n_Chars	0	16#0004				2
n_Chars	1					3

Example Signed/unsigned 32-bit data:

	Offset	ASCII codes	Hex. equivalent			Offset	Converted hex. characters
s1_Start	0	16#4241	BA	Þ	d	0	16#CDAB
s1_Start	1	16#4443	DC			1
n_Chars	0	16#0004				2
	1	16#0000				3
	2					4

Example Signed/unsigned 16-bit data:

	Offset	ASCII codes	Hex. equivalent			Offset	Converted hex. characters
s1_Start	0	16#3231	21	Þ	d	0	16#3412
	1	16#3433	43			1	16#7856
	2	16#3635	65			2
	3	16#3837	87			3
n_Chars	0	16#0008				4
n_Chars	1					5

Example Signed/unsigned 16-bit data, odd number of characters:

If an odd number of characters is being converted, 0 will be entered for bit position 0–3 of the last converted byte.

	Offset	ASCII codes	Hex. equivalent			Offset	Converted hex. characters
s1_Start	0	16#3231	21	Þ	d	0	16#3412
	1	16#3433	43			1	16#7056
	2	16#3635	65			2
	3	16#3837	87			3
n_Chars	0	16#0007				4
n_Chars	1					5

Example

POU header

All input and output variables used for programming this function have been declared in the POU header. The same POU header is used for all programming languages.

	VAR
		bStart: BOOL:=FALSE;
			(*activates the function*)
		wASCIIInput: WORD:=16#3031;
		wConversionResult: WORD:=0;
	END_VAR

POU body

When the variable bStart is set to TRUE, the function is carried out.

LD body

BODY
    WORKSPACE
        NETWORK_LIST_TYPE := NWTYPELD ;
        ACTIVE_NETWORK := 0 ;
    END_WORKSPACE
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 6 ;
        NETWORK_BODY
B(B_CONTACT,,bStart,5,2,7,4,);
B(B_VARIN,,wASCIIInput,11,3,13,5,);
B(B_VARIN,,2,11,4,13,6,);
B(B_VAROUT,,wConversionResult,23,3,25,5,);
B(B_F,FP_ASCII_TO_HEX!,,13,1,23,6,,?DEN?Ds_Start?Dn_Chars?AENO?Cd);
L(1,3,5,3);
L(7,3,13,3);
L(1,0,1,6);
        END_NETWORK_BODY
    END_NET_WORK
END_BODY

ST body

If (bStart) then
    FP_ASCII_TO_HEX(s_Start := wASCIIInput, 
                    n_Chars := 2, 
                    d => wConversionResult);
End_if;