Mitsubishi MELSEC Q Series Programming Manual page 668

EXPD(P)
Program Example
(1) The following program performs an exponent operation on the value set by the 2 BCD digits
at X20 to X31, and stores the results as a 64-bit floating decimal point real number at D0 to
D3.
[Ladder Mode]
[List Mode]
Step
[Operations involved when value designated by X20 to X31 is 13]
X31 X20
0 1 3
BCD value
*1: The operation result will be under 2
loge 2
Because setting a value of over 710 will return an operation error, turn M0 ON if a value of over 710 has been
set to avoid the error.
7-294
Instruction Device
Conversion Conversion to
1 2
D20
b15 b0
to BIN floating-point
13
BIN BIN value FLTD
1024
= 709.7832.
Conversion from natural logarithm to common logarithm
In the CPU module, calculation is made using a natural logarithm.
To obtain a common logarithm value, enter in,
divided by 0.43429.
Inputs data used for exponent
operation ( ).
1
Checks the range of the value used
for operation. *1
Converts the input data into a 64-bit
floating-point real number (
Executes exponent operation (
D13 D12 D11 D10
13
64-bit floating-point
real number
1024
if the BCD value of X20 to X31 is less than 709, from the calculation
S
).
2
).
3
D3 D2 D1
3 EXP operation
442413.4
EXPD
64-bit floating-point
real number
a common logarithm value
D0