A S S e r i e s O p e r a t i o n Ma n u a l5 - 8_55.2.2 Floating-point NumbersThe floating-point numbers are represented by decimal points in ISPSoft. For example, the floating-pointnumber of 500 is 500.0. Refer to Section 2.2.2 in the AS Series Programming Manual for more information.5.2.2.1 Single-precision Floating-point NumbersFloating-point numbers are represented by the 32-bit register. The representation adopts the IEEE754standard, and the format is as follows.S E xpo ne nt Ma nti ssa8 -b it 2 3- bi tb 31 b 0S ig n b it0 : Po siti ve1 : Neg ati veEquation: ( ) 127;.121 =××− − BMBESThe single-precision floating-point numbers range from ±2-126 to ±2+128, and correspond to the range from±1.1755×10-38 to ±3.4028×10+38.The AS series PLC uses two consecutive registers to form a 32-bit floating-point number. Take (D1, D0) forexample.S E7 E6 E5 E1 E0 A22 A21 A20 A6 A5 A4 A3 A2 A1 A0b0b1b2b3b4b5b6b20b21b22b23b24b28b29b30b312 2 2 2 2 2 2 2 2 2 2 2 22 2D1 (b 15 ~b 0) D0 (b 15 ~b 0)E xp on en t ( 8 b its) Ma nt issa (2 3b it s)Ma nt issa sign b it (0 : Po sit ive; 1: Ne ga tive)W hen b 0~ b3 1 a re zeros, t he con te nt is zero .T he pos ition w here the d eci mal point is hid denExample 1:23 is represented by a single-precision floating-point number.Step 1: Convert 23 into the binary number, i.e. 23.0=10111.Step 2: Normalize the binary number, i.e. 10111=1.0111 ×24 (0111 is the mantissa, and 4 is the exponent.).Step 3: Get the value of the exponent.∵ E-B=4→E-127=4 ∴ E=131=100000112Step 4: Combine the sign bit, the exponent, and the mantissa to form the floating-point number.0 10000011 011100000000000000000002 =41B80000 16
