3. Instruction Set
3-273
Function code:
‘0’ ‘1’: Reading several bit devices
‘0’ ‘2’: Reading several bit devices (read-only devices)
‘0’ ‘3’: Reading several word devices
‘0’ ‘4’: Reading several word devices (read-only devices)
‘0’ ’5’: Writing a state in a single bit device
‘0’ ‘6’: Writing data in a single word device
‘0’ ’F’: Writing states in bit devices
‘1’ ‘0’: Writing data in word devices
‘1’ ‘7’: Reading word devices and writing data in word devices
Data characters:
The data sent by the user
LRC checksum:
LCR checksum is 2’s complement of the value added from Address to Data Characters.
For example: 01H + 03H + 21H + 02H + 00H + 02H = 29H. 2’s complement of 29H = D7H.
End word (END):
Fix the END as END Hi = CR (0DH), END Lo = LF (0AH)
Example:
Read 2 continuous data stored in the registers of the drive at address 01H (see the table below).
The start register is at address 2102H.
Inquiry message: Response message:
STX ‘: ’ STX ‘: ’
Address
‘0’
Address
‘0’
‘1’ ‘1’
Function code
‘0’
Function code
‘0’
‘3’ ‘3’
Start address
‘2’
Number of data
(count by byte)
‘0’
‘1’ ‘4’
‘0’
Content of start
address
2102H
‘1’
‘2’ ‘7’
Number of data
(count by word)
‘0’ ‘
7’
‘0’ ‘0’
‘0’
Content of address
2103H
‘0’
‘2’ ‘0’
LRC Checksum
‘D’ ‘
0’
‘7’ ‘0’