Siemens SIMATIC S7-1200 - Page 360

Extended instructions
9.2 String and character
S7-1200 Programmable controller
360 System Manual, V4.2, 09/2016, A5E02486680-AK
Table 9- 43 HTA instruction
LAD / FBD
SCL
Description
ret_val := HTA(
in:=_variant_in_,
n:=_uint_in_,
out=>_variant_out_);
Converts packed hexadecimal digits to their corresponding ASCII
character bytes.
Table 9- 44 Data types for the HTA instruction
Parameter and type
Data Type
Description
IN
IN
Variant
Pointer to input byte array
N IN UInt Number of bytes to convert (each input byte has two 4-bit nibbles and
produces 2N ASCII characters)
RET_VAL
OUT
Word
Execution condition code
OUT
OUT
Variant
Pointer to ASCII character byte array
Conversion begins at the location specified by parameter IN and continues for N bytes. Each
4-bit nibble converts to a single 8-bit ASCII character and produces 2N ASCII character
bytes of output. All 2N bytes of the output are written as ASCII characters 0 to 9 through
uppercase A to F. The parameter OUT specifies a byte array and not a string.
Each nibble of the hexadecimal byte is converted into a character in the same order as they
are read in (left-most nibble of a hexadecimal digit is converted first, followed by the right-
most nibble of that same byte).
Table 9- 45 Examples: Hexadecimal -to- ASCII (HTA) conversion
IN value
N
OUT character bytes
ENO (ENO always TRUE after HTA execution)
W#16#0123 2 '0123' TRUE
DW#16#123AF012
4
'123AF012'
TRUE