Delta DVP-10PM, Applications Manual

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5
Categories and Use of Basic Application Instructions
DVP-PM Application Manual 5-105
API Mnemonic Operands Function
126 D LOG P Float Logarithm Operation
Controllers
20PM 10PM
Bit Devices Word Devices Program Steps Type
OP
X Y M S F H KnX KnY KnM KnS T C D V Z
S
1
* *
S
2
* *
D *
DLOG, DLOGP: 9 steps
Operands:
S
1
: Base
S
2
: Antilogarithm
D
: Operation result
Explanations:
1. Perform logarithm operation with
S
1
as the base and
S
2
as the antilogarithm and save the result in
D
.
2. F refers to floating point input. Be sure to add a decimal point when using it.
3. Only 32-bit instructions DLOG and DLOGP are applicable.
4. Only a positive number is valid for
S
. Register
D
has to be 32-bit format. Operation is conducted in floating point
value, so the value in
S
needs to be converted into floating value before logarithm operation.
5. Logarithm operation:
S
1
D
= S
2
,
D =
? Æ Log
S1
S2
= D
Example: Assume
S
1
= 5,
S
2
= 125,
D
= log
5
125
= ?
S
1
D =
S
2
Æ
5 D = 125
Æ
D
= log
5
125
= 3
6. Flags:
OX O100
Zero flag M1808 M1968
Borrow flag M1809 M1969
Carry flag M1810 M1970
a) If the absolute value of the result exceeds the max floating point value, carry flag will be ON.
b) If the absolute value of the result is less than min. floating point value, borrow flag will be ON.
c) If the conversion result is 0, zero flag will be ON.
Program Example:
1. When M0 = ON, convert (D1, D0) and (D3, D2) to binary floating value and save the result in register (D11, D10)
and (D13, D12) individually.
2. When M1= ON, perform natural logarithm operation with (D11, D10) as base and (D13, D12) as antilogarithm.
The value is saved in register (D21, D20) in binary floating format.
3. When M2 = ON, convert the value in (D21, D20) into decimal floating point value and save the result in (D31,
D30). (At this time, D31 indicates powers of 10 for D30).
M0
DFLT D0 D10
M1
DLOG D10 D12
M2
DEBCD D20 D30
DFLT D2 D12
D20
Points to note:
For floating point operations, see “5.3 Numeric Values for Data Processing”