HP 1630A Operating And Programming Manual page 115

Using HP-113 or HP-IL Interface Model 1630A/D/G
The first way to interpret the remaining number is to use the floating point translation which can be generalized
as :
(The mantissa is always a fraction less than one.)
In this case, the binary point is assumed left of byte 15 . The mantissa could then be represented in decimal as
follows:
Byte Position :
Byte 15 Byte 16 Byte 17
Hexadecimal :
9
8
0 0 0 0
Binary : 1001 1000 0000 0000
0000 000
Decimal : (1X2-14) +
(1X2-4)
+
(1X2-5) = .594 = (MANTISSA)
Therefore, the equation (MANTISSA) X 2(EXPONENT) reveals:
Another method of decoding this number is to move the binary point to the right the same number of places as
the exponent indicates. Then, interpret the binary number directly as a number greater than one as indicated
below.
Hexadecimal: 9 8 0 0 0 0
Binary : .100
1
1 1000 0000 0000 0000 0000
9- 8
7 places
(MANTISSA) X 2 (EXPONENT)
( .594) X 2(7) = 76 runs
1001100=64+8+4=76 runs
1 X 2-5
1 X 2-4
1 X 2- 14
The exponent is a 7-bit 2's complement number, therefore, positive value exponents are not required to be
converted to normal binary since they are the same . However, a negative exponent value must first be
translated to normal binary representation before interpreting the exponent as a negative number.
The following example of the State Time Interval Overview Learn String parameter for Total Time
demonstrates a negative value exponent .
Parameter: Total Accumulated Time (State Time Interval Overview Learn String)
Byte Position : 18 19 20 21
Format :
(R) (R)
(R) (R)
Hexadecimal : E8 98 91 5E