Delta Electronics AH500, Manual

Page: 202 / 547

C h a p t e r 5 A p p l i e d I n s t r u c t i o n s
5 - 8 7
API Instruction code Operand Function
126 D LOG P S
1
, S
2
, D
Logarithm of a binary
floating-point number
Device X Y M S K 16# F KnM KnS D W T C V Z
S
1

 
S
2

 
D
 
Pulse instruction 16-bit instruction 32-bit instruction (9 steps)

–

E xp la nat io n

The logarithm of the value in S
2
with respect to the value in S
1
is
calculated, and the operation result is stored in D .

S
1
: Device in which the base is stored; S
2
: Source device; D : Device in
which an operation result is stored

The values in S
1
and S
2
can only be positive values. D must be a 32-bit
register, and the values in S
1
and S
2
must be floating-point values.

S
1
D
= S
2
→
D =Log
S1
S
2

If the absolute value of an oepration result is greater than the maximum
floating-point value available, a carry flag will be ON.

If the absolute value of an oepration reuslt is less than the minimum
floating-point value available, a borrow flag will be ON.

If an operation result is 0, a zero flag will be ON.

SM1064 is the zero flag in an Ox motion subroutine, and SM968 is the
zero flag in O100.

SM1065 is the borrow flag in an Ox motion subroutine, and SM969 is the
borrow flag in O100.

SM1066 is the carry flag in an Ox motion subroutine, and SM970 is the
carry flag in O100.
E xa mple

When M0 is ON, the values in (D1, D0) and (D3, D2) are converted into
binary floating-point values, and the conversion results are stored in
(D11, D10) and (D13, D12) respectively.

When M1 is ON, the logarithm of the binary floating-point value in (D13,
D12) with respect to the binary floating-point value in (D11, D10) is
calculated, and the operation result is stored in (D21, D20).
M0
DFLT D 0 D 10
M1
D LOG D 10
D12
DFLT D 2 D 12
D 20
A dditio nal

re m ark
Please refer to section 5.3 for more information about performing
operations on floating-point numbers.