Loge (Natural Logarithm) - IDEC MICROSmart FC6A Series Ladder Programming Manual

22: L
OGARITHM
Introduction
This chapter describes logarithm function and power function instructions that are are used to calculate logarithms and powers for
specified data.

LOGE (Natural Logarithm)

LOGE(F)
*****
Valid Devices
Device
S1 (Source 1)
D1 (Destination 1)
For valid device address ranges, see "Device Addresses" on page 2-1.
When the operation result is not within the range between –3.402823 × 10
38
3.402823 × 10 , special internal relay M8003 (carry or borrow) is turned on except when the result is 0. For details, see "Carry and Borrow in
Floating-Point Data Processing" on page 3-8.
When the value of S1 (source 1) is 0, a user program execution error occurs.
When the value of S1 (source 1) is less than 0, a user program execution error occurs.
When the data designated by source device S1 does not comply with the normal floating-point format, a user program execution error occurs, and
the execution of the instruction is canceled. The value of D1 is left unchanged and the next instruction is executed.
When a user program execution error occurs, special internal relay M8004 and ERR LED on the FC6A Series MICROSmart are turned on. For details
about the user program execution errors, see "User Program Execution Errors" on page 3-10.
Since the LOGE instruction is executed in each scan while input is on, a pulse input from a SOTU or SOTD instruction should be used.
Valid Data Types
W (word) —
I (integer) —
D (double word) —
L (long) —
F (float) X
Example: LOGE
LOGE(F)
SOTU
I1
/ P
OWER
log S1·S1+1 → D1·D1+1
e
S1 D1
When input is on, the natural logarithm of the binary data assigned by source device S1 is stored
*****
to the destination assigned by device D1.
Function
Binary data to convert into natural logarithm
Destination to store conversion results
Since floating point data is used, the source and destination devices use two consecutive data registers.
S1 D1
D10 D20
FC6A S MICROS
ERIES MART
I
NSTRUCTIONS
I Q
— —
— —
38
and –1.175495 × 10
When input I1 is on, the natural logarithm of the binary data of data registers D10 and
D11 assigned by source device S1 is stored to data registers D20 and D21 assigned by
destination device D1.
86.0 → 4.454347
log
e
S1
86.0
D10·D11
L P M
ADDER ROGRAMMING
M R T C D P
— — — — X —
— — — — X —
–38
or between 1.175495 × 10
D1
D20·D21
FC9Y-B1726
ANUAL
Constant Repeat
X —
— —
–38
and
4.454347
22-1