Chapter 8 Dedicated Protocol Communication
8-9
(3) Response format (For PLC’s ACK Response)
■ Read Response of Continuous Variable (PLC
MMI)
Item
Size(byte)
Description
Instruction
2
h0055 : Read Response
Data type
2
h0014 : Block Type
Reserved area
2
h0000 : Don’t Care
Error status
2
Normal if it is 0, abnormal if not 0.
Error code
2
If Error State is abnormal, the lower byte is the error code.
Number of blocks
h0001 : If Error State is normal
Number of data
2
The Size of Data in byte.
Data
Data size
Data to read; up to 1400 bytes
Format
name
Header
Instruction
Data
type
Reserved
area
Error
status
Number
of blocks
Number
of data
Data
Code
(Ex.)
...
h0055
h0014
h0000
h0000
h0001
h0006
h012345
6789AB
▷
Number of data means the number of bytes in Hexadecimal number.
(4) Response format (For PLC’s NAK Response)
Format
name
Header
Instruction
Data type
Reserved
area
Error status
Error code
(Hex 1 Byte)
Code (Ex.)
...
h0055
h0014
h0000
hFFFF
h21
Notes
1) Error code displays the type of error in 1 byte of Hexadecimal code.
Refer to ‘Error Code Table’ for more details.
