IDEC MICROSmart FC6A Series Ladder Programming Manual

22: L OGARITHM / P OWER I NSTRUCTIONS
22-2 FC6A S ERIES MICROS MART L ADDER P ROGRAMMING M ANUAL FC9Y-B1726
LOG10 (Common Logarithm)
Valid Devices
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
and –1.175495 × 10
–38
or between 1.175495 × 10
–38
and
3.402823 × 10
38
, 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 LOG10 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
Example: LOG10
log
10
S1·S1+1 → D1·D1+1
When input is on, the common logarithm of the binary data assigned by source device S1 is
stored to the destination assigned by device D1.
LOG10(F) S1
*****
D1
*****
Device Function I Q M R T C D P Constant Repeat
S1 (Source 1) Binary data to convert into common logarithm — — — — — — X — X —
D1 (Destination 1) Destination to store conversion results — — — — — — X — — —
W (word) — Since floating point data is used, the source and destination devices use two consecutive data registers.
I (integer) —
D (double word) —
L (long) —
F (float) X
When input I1 is on, the common 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.
I1
S1
D10
LOG10(F) D1
D20
SOTU
log
10
0.0000278 → –4.555954
D1S1
0.0000278
D10·D11
–4.555954
D20·D21

IDEC MICROSmart FC6A Series Specifications

General

Brand	IDEC
Model	MICROSmart FC6A Series
Category	Computer Hardware
Language	English