Delta Electronics AC Motor Drive VFD-E - Manual (Page 335)

Appendix D How to Use PLC Function|
D-52 Revision June 2008, 04EE, SW--PW V1.11/CTL V2.11
Explanations:
1. See the specifications of each model for their range of use.
2. This instruction adds S1 and S2 in BIN format and store the result in D.
3. The highest bit is symbolic bit 0 (+) and 1 (-), which is suitable for algebraic addition, e.g.
3 + (-9) = -6.
4. Flag changes in binary addition
16-bit command:
A. If the operation result ＝ 0, zero flag M1020 = On.
B. If the operation result ＜ -32,768, borrow flag M1021 = On.
C. If the operation result ＞ 32,767, carry flag M1022 = On.
Program Example 1:
16-bit command:
When X0 = On, the content in D0 will plus the content in D10 and the sum will be stored in D20.
X0
ADD D0 D10 D20
Remarks:
Flags and the positive/negative sign of the values:
-2, -1, 0 -32,768 -1, 0 1 32,767 0 1 2
-2, -1, 0 -2,147,483,648 -1, 0 1 2,147,483,647 0 1 2
16 bit: Zero flag Zero flag Zero flag
Borrow flag
The highest bit
of the data
= 1 (negative)
32 bit: Zero flag
Zero flag
Zero flag
The highest bit
of the data
= 0 (positive)
Carry flag
Borrow flag
Carry flag
The highest bit
of the data
= 1 (negative)
The highest bit
of the data
= 0 (positive)