3-3
Section 3 Inverter Communication
3-3 Data Read Program
The remote data read (R_READ) FB is used to receive data from an inverter.
(1) FB format
(2) Explanation of terminals
Note: The receive data is stored in RD in the following manner.
R_READ
REQ
MODULE_NO
CHANNEL_NO
STATION_NO
VAR_TYPE
REMOTE_VAR
SIZE
RD
BOOL
BOOL
INT
Array 1
Array 2
DONE
ERROR
STATUS
REMOTE_VAR
RD
BOOL
UINT
UINT
UDINT
UINT
Array 1
UINT
Array 2
Terminal name
Data type
I/O
Description
REQ
BOOL
IN
Request to read
At the rising edge of this signal, the receive data stored in the receive buffer is
read into RD.
MODULE_NO
UINT
IN
RS-485 port No. designation
Fixed to UNIT#8
CHANNEL_NO
UINT
IN
Communication type code
Designates the type of communication. Fixed to UINT#0.
STATION_NO
UDINT
IN
Sets the RS-485 station No. of the inverter. (1 to 255)
VAR_TYPE
UINT
IN
Variable specification method Fixed to UINT#1
REMOTE_VAR
Array 1
IN_OUT
Address specification
2-word UINT type array variable is connected.
Enters "function code" of the inverter in the first word and "write No." in the second
word.
SIZE
UINT
IN
Receive data size Designates the size of read data by the number of words +1.
SD
Array 2
IN_OUT Receive data The read data is stored. (see note)
DONE
BOOL
OUT
Normal end Set ON for one scan period when reading is completed successfully.
ERROR
BOOL
OUT
Transmission error
Set ON for one scan period if error occurred during the reading operation.
STATUS
INT
OUT
Status
The content of occurred transmission error is indicted by a code. For details, refer
to "3-4 Error Code".
N <= 84
Format of prepared receive data (RD)
No. of receive data bytes
Data 2
Data 1
Data 4
Data 3
Data N
Data N-1
0
15
Receive data size
(SIZE)
