Filter
Top Products
6 - 4
MELSEC-
A
6 EXCHANGING DATA WITH AN EXTERNAL DEVICE
(4) Setting the buffer memory
The following buffer memories are related to the transmission of data.
R2 buffer
memory address
Name Details
R2
0H
Transmission area
head address
designation
Designate the head address of the R2 buffer memory to be used as the
transmission area.
Always designate
R2
200H or above, which is the user free area.
Set so that the area is not duplicated with areas used by other functions.
Setting range: 200H to 7FEH (Default value: 200H)
R2
1H
Transmission area size
designation
Designate the size of the R2 buffer memory used as the transmission area.
(Transmission data size designation area + transmission data designation
area size)
Set the transmission area size to be 2H or more.
R2
102H
Word/byte unit
designation
Set the transmission data and reception data unit (word/byte) for when
exchanging data between the R2 and external device.
0 : Word unit (default value)
1 : Byte unit
∗
This is also used as the unit of the values handled in the actual transmission
data size storage area (
R2
1B4H) and OS reception area data size
storage area (
R2
1B6H).
R2
11AH
Transmission timeout
time designation
Designate the timeout time from when the transmission request signal
(RYn0) turns ON (a trigger is generated during monitor transmission), the
transmission starts to when the transmission ends.
When the transmission timeout is applied, the transmission error complete
signal (RXn1) turns ON, and the BB11
H is stored in the transmission error
code area (
R2
1B1H).
0 : Unlimited wait
1 to 32767 : Transmission timeout time (
×
100ms)
R2
1B4H
Actual transmission
data size storage
The actually transmitted data size is stored when transmission is completed.
When transmitting frames, the head and end frames will also be included in
the transmission data size.
If ASCII-BIN conversion is carried out, the transmission data size after
conversion will be stored.
The data size unit follows the word/byte unit designation (
R2
102H).