Chapter 5 CPU and Module Devices
5-7
Binary Number
(BIN)
Octal Number
(OCT)
Decimal Number
(DEC)
Binary Code Decimal
(BCD)
Hexadecimal Number
(HEX)
1111 15 - F
10001
17 0001 0001 11
5.2.2 Floating-point Numbers
Floating-point numbers are represented by decimal points in ISPSoft. For example, the floating-point number 500 is
represented as 500.0.
5.2.2.1 Single-precision Floating-point Numbers
Floating-point numbers are represented by a 32-bit register. The representation adopts the IEEE754 standard, and the
format shown in the following picture.
S
Exponent
Mantissa
8-bit 23-bit
b
31
b
0
Sign bit
0: Positive
1: Negative
Equation:
The single-precision floating-point numbers range between ±2
-126
to ±2
+128
, and correspond to the range between
±1.1755×10
-38
to ±3.4028×10
+38
.
The DVP-ES3 Series PLC uses two consecutive registers for a 32-bit floating-point number. Take (D1, D0) for example.
S E7 E6 E5 E1 E0 A22 A21 A20 A6 A5 A4 A3 A2 A1 A0
b0b1b2b3b4b5b6b20b21b22b23b24b28b29b30b31
2 2 2 2 2 2 2 2 2 2 2 2 22 2
D1(b15~b0) D0(b15~b0)
Exponent (8 bits)
Mantissa (23bits)
Mantissa sign bit (0: Positive; 1: Negative)
When b0~b31 are zeros, the content is zero.
The position where the decimal point is hidden