Write Calculation - Mitsubishi MELSEC-Q EQ-V680D1 User Manual

6. HOW TO COMMUNICATE WITH ID TAGS

6.2.6 Write calculation

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The Write Calculation command performs an addition (subtraction) operation on the
data of the number of bytes specified in the number of processed points specification
area (Un\G4, Un\G4004) from the address specified in the head address specification
area (Un\G3, Un\G4003), and then writes the result to the same address of the ID tag.
The data subject to the addition (subtraction) operation are stored in the command
option specification area (Un\G5, Un\G4005).
The calculation result data are also stored in the data storage area (Un\G100 to
Un\G101, Un\G4100 to Un\G4101).
When an addition calculation result indicates overflow, the calculation result is not
written to the ID tag, the status flag (bit 4) of the error details storage area (Un\G41,
Un\G4041) turns ON, error detection (X5, XD) turns ON, and the operation ends in
error.
Similarly, when a subtraction calculation result indicates underflow, the calculation
result is not written to the ID tag, the status flag (bit 4) of the error details storage area
(Un\G41, Un\G4041) turns ON, error detection (X5, XD) turns ON, and the operation
ends in error.
(1) Example of use
(a) When F012 is added to the four bytes from address 0010
H
Buffer memory
Address
b15
Option
Un\G5
F0 12
H
Data before execution
Addition data
Data after execution
(b) When F012 is subtracted to the four bytes from address 0010
H
Buffer memory
Address
b15
Option
Un\G5
F0 12
H
Data before execution
Subtraction data
Data after execution
ID tag
Before
b0 b7
execution
EF
0010
H
FF
0011
H
0012 56
H
78
0013
H
b7 b0 b7 b0 b7
11101111 11111111
00000000 00000000
11110000 00000000
ID tag
Before
b0 b7
execution
0010 F0
H
00
0011
H
46
0012
H
8A
0013
H
b7 b0 b7 b0 b7
11110000 00000000
00000000 00000000
11101111 11111111
H
b0 b7
0010
H H
0011
H
H
0012
H
H
0013
H
H
b0 b7 b0
01010110 01111000
11110000 00010010
01000110 10001010
b0 b7
0010
H
H
0011
H
H
0012
H H
0013
H
H
b0 b7 b0
01010110 10001010
11110000 00010010
01010110 01111000
ID tag
After
b0
execution
F0
H
00
H
46
H
8A
H
EFFF 5678
H H
0000 F012
H H
F000 468A
H H
H
ID tag
After
b0
execution
EF
H
FF
H
56
H
78
H
F000 468A
H H
0000 F012
H H
EFFF 5678
H H
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