IDEC microsmart pentra, Руководство по программированию

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FT1A S
MART
A
XIS
U
SER
’
S
M
ANUAL
FT9Y-B1382 22-3
22: L
OGARITHM
/ P
OWER
I
NSTRUCTIONS
EXP (Exponent)
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
and 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 larger than 3.402823  10
38
, causing an overflow, the destination device designated by D1 stores a
value of minus or plus infinity.
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 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 EXP 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: EXP
e
S1·S1+1
 D1·D1+1
When input is on, e is raised to the power S1·S1+1 designated by source device S1 and is stored
to the destination designated by device D1.
e (base of natural logarithm) = 2.7182818
EXP(F) S1
*****
D1
*****
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 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, e is raised to the data of data registers D10 and D11 designated by
source device S1 and the operation result is stored to data registers D20 and D21
designated by destination device D1.
e
2
= 2.7182818
2
 7.389056
I1
S1
D10
EXP(F) D1
D20
SOTU
D1 S1
2.0 D10·D11 7.389056 D20·D21