Delta DVP-ES2/EX2/SS2/SA2/SX2/SE manual Log

3. Instruction Set

API

126

Mnemonic			Operands	Function
D	LOG	P		Float logarithm operation

Controllers

ES2/EX2 SS2 SA2 SX2

SE

Type

Bit Devices

Word devices

Program Steps

OP

X

Y

M

S

K

H

KnX

KnY

KnM

KnS

T

C

D

E

F

DLOG, DLOGP: 13 steps

S1

*

*

*

S2

*

*

*

D

*

16-bit

PULSE

32-bit

ES2/EX2

SS2

SA2

SX2

ES2/EX2

SS2

SA2

SX2

ES2/EX2

SS2

SA2

SX2

SE

SE

SE

Operands:

S1: Base S2: Antilogarithm D: Operation result

Explanations:

1.Perform logarithm operation with S1 as the base and S2 as the antilogarithm and save the result in D.

2.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.

3.Logarithm operation: S1D = S2, D = ? LogS1S2 = D

Example: Assume S1 = 5, S2 = 125, S1D = S2, D = ? 5D = 125 D = LogS1S2 = log5125 = 3.

4.Flags: M1020 (Zero flag), M1021 (Borrow flag) and M1022 (Carry flag).

If absolute value of the result is larger than max. floating value, carry flag M1022 = ON.

If absolute value of the result is smaller than min. floating value, borrow flag M1021 = ON. If the conversion result is 0, zero flag M1020 = 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 logarithm operation with (D11, D10) as base and (D13, D12) as antilogarithm. The results are 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)

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