Mitsubishi Electric MELSEC-Q00U(J)CPU User Manual page 540

(4)
Replacing the High Performance model QCPU with the Universal model QCPU
(a) Replacing all single-precision floating-point operation instructions with double-
precision floating-point operation instructions
Single-precision floating-point data occupy two points of word device per data.
On the other hand, four points are required per double-precision floating-point data.
Therefore, all device numbers for storing floating-point data need to be reassigned.
Replacing the floating-point operation [A
Ex.
precision.)
• Device assignment
Application
Data A
Data B
Data C
Result
• Program before replacement
• Program after replacement
538
Before replacement
Device Data type
D0 to D1
D2 to D3
Floating-point data
(single precision)
D4 to D5
D6 to D7
B + C] (Changing all floating-point data into double
×
After replacement
Application
Data A D0 to D3
Data B D4 to D7
Data C D8 to D11
Result D12 to D15
Device Data type
Floating-point data
(double precision)
Operation is performed using
double-precision floating-point
data.