Campbell TX321, Product Manual, Page: 59 / 86

Appendix C. GOES Data Formats
C-3
bit and is set if necessary by the transmitter. Binary numbers are transmitted
MSB (most significant bit) first.
Because only 6 bits are used in each byte, the range that a byte or series of
bytes can represent is diminished. For example:
1-byte encoded unsigned integer 0 to +63
1-byte encoded signed integer –32 to +31
2-byte encoded unsigned integer 0 to +4094
2-byte encoded signed integer –2048 to +2047
3-byte encoded unsigned integer 0 to +262143
3-byte encoded signed integer –131072 to +131071
4-byte encoded unsigned integer 0 to +16777215
4-byte encoded signed integer –8388608 to +8388607
A Pseudo Binary data message is not easily human readable and therefore
relies on a data processing element within the flow of data reception to decode
and transform.
C.3.1 FP2, 16-bit Floating Point Number
The FP2 data format uses 16 bits to represent a variable-precision floating
point number. FP2 has a total range of -7999 to 7999 and variable precision of
0.001 to 1. It also has the ability to /– infinity and NAN, most
commonly used to indicate a computational or measurement error. The
following tables present the numeric ranges and their associated precision.
Also shown is a description of each bit and their usage in calculating a finished
value.
Range Max Precision
–7.999 to 7.999 0.001
–79.99 to 79.99 0.01
–799.9 to 799.9 0.1
–7,999 to 7,999 1
Name Bit Description
Sign (S) 15 (MSB)
Specifies the sign of the value.
0 = positive, 1 = negative.
Exponent (E) 14 and 13
Specifies the magnitude of the
negative decimal exponent.
Mantissa (M) 12 to 0 (LSB) Specifies the magnitude of the
13-bit mantissa, 0 to 8191
S E M FP2 Value Is =
0 0 8191 + infinity
1 0 8191 – infinity
1 0 8190 NAN
0 or 1 0 to 3 0 to 7999 (–1 ^ S) • (10 ^ –E) • M