IDEC microsmart pentra, Programming Manual

Page: 278 / 344

22: L
OGARITHM
/ P
OWER
I
NSTRUCTIONS
22-4 FT1A S
MART
A
XIS
U
SER
’
S
M
ANUAL
FT9Y-B1382
POW (Power)
Applicable CPU Modules
Valid Devices
For the valid device address range, see pages 6-1 and 6-2 (Basic Vol.).
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
to 3.402823 
10
38
, special internal relay M8003 (carry or borrow) is turned on, except when the result is 0. For details, see Chapter 4 “Carry and Borrow in
Floating-Point Data Processing” on page 4-18.
When the operation result is between –1.175495  10
–38
and 1.175495  10
–38
, the destination device designated by D1 stores 0. When the
operation result is less than –3.402823  10
38
or greater than 3.402823  10
38
, causing an overflow, the destination device designated by D1 stores
a value of minus or plus infinity.
When one of the following conditions occurs, a user program execution error occurs and 0 is stored in D1.

The data designated by source device S1 is less than 0 and the data designated by source device S2 is not an integer.

The data designated by source device S1 is 0 and the data designated by source device S2 is less than or equal to 0.
When the data designated by source device S1 or S2 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 CPU module are turned on. For details about the
user program execution errors, see Chapter 4 “User Program Execution Errors” on page 4-21.
Since the POW instruction is executed in each scan while input is on, a pulse input from a SOTU or SOTD instruction should be used as required.
Valid Data Types
Example: POW
S1·S1+1
S2·S2+1
 D1·D1+1
When input is on, data designated by source device S1 is raised to the power S2·S2+1
designated by source device S2 and the operation result is stored to the destination
designated by device D1.
POW(F) S1
*****
D1
*****
S2
*****
FT1A-12 FT1A-24 FT1A-40 FT1A-48 FT1A-Touch
X X X X X
Device Function I Q M R T C D Constant Repeat
S1 (Source 1) Binary data of base — — — — — — X X —
S2 (Source 2) Binary data of exponent — — — — — — X X —
D1 (Destination 1) Destination to store results — — — — — — X — —
W (word) — Since the floating point data type 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 data of data registers D10 and D11 designated by
source device S1 is raised to the power D20·D20+1 designated by source
device S2 and the operation result is stored to data registers D30 and D31
designated by destination device D1.
4
1.25
 5.656856
I1
S2
D20
POW(F) D1
D30
SOTU
S1
D10
S2 S1
4.0
D10·D11
1.25
D20·D21
D1
5.656856
D30·D31