Siemens Simatic S7 Series System Manual page 206

Program instructions
7.5 Convert
The following figure describes the format operand (FMT) for the RTA instruction. The size of
the output buffer is assigned by the ssss field. A size of 0, 1, or 2 bytes is not valid. The
number of digits to the right of the decimal point in the output buffer is assigned by the nnn
field. The valid range of the nnn field is 0 to 5. If you assign 0 digits to the right of the decimal
point, then the value is converted without a decimal point. The output buffer is filled with
ASCII spaces for values of nnn greater than 5 or when the assigned output buffer is too
small to store the converted value. The c bit specifies the use of either a comma (c=1) or a
decimal point (c=0) as the separator between whole number and fraction.
The following figure also shows examples of values that are formatted using a decimal point
(c=0) with one digit to the right of the decimal point (nnn=001) and a buffer size of six bytes
(ssss=0110).
FMT Operand for the Real to ASCII (RTA) instruction
Example: ASCII to Hexadecimal
LAD
The "x" indicates that the "nibble" (half of a byte) is unchanged.
1
206
STL
Network 1
LD I3.2
ATH VB30, VB40, 3
System Manual, 09/2015, A5E03822230-AC
S7-200 SMART