Instruction manual

3
6. ZM-Link 3-29
Serial Communications
Sum Check Code (SUM): 2 bytes
Data is added up (SUM), and the lower one byte (8 bits) of the sum is converted into the
2-digit ASCII code (hexadecimal). A sum check code is shown below.
Example: Transmission mode: without CR/LF, with sum check
Command: 20 (data read)
Address: 10 words from $u1000 (03E8H)
When reading, a sum check will be performed as shown below.
Response Code: 2 bytes
[ACK]
This code is received at normal termination.
00H (3030: ASCII)
[NAK]
This code is received at abnormal termination. (ASCII) Refer to the next page for more
information.
NAK: Error Codes
02H: Overrun/Framing error
An overrun or framing error is detected in the received data. Send the command
again.
03H: Parity error
A parity error is detected in the received data. Send the command again.
04H: Sum check error
A sum error occurs with the received data.
06H: Count error
The memory read/write count is “0.”
0FH: ETX error
No ETX code is found.
11H: Character error
A character not used in the received data is found. (other than 0 to F) Check the
character and send the command again.
12H: Command error
An invalid command is given.
13H: Memory setting error
The address or device number is invalid.
STX
ZM-300 Port
number
Command
Read
Words
Memory
Model
Memory
Type
Address System reserved ETX SUM
01H 20H 0AH 00H 00H 03E8H 0 0 0 0 0 0 0 0 0 0H B9H
02H 30H31H 32H30H 30H41H 30H30H 30H30H 30H 33H 45H 38H 30H 30H 30H 30H 30H 30H 30H 30H 30H 30H 03H 42H39H
02H + 30H + 31H + 32H + 30H + 30H + 41H + 30H + 30H + 30H + 30H + 30H + 33H + 45H + 38H
+ 30H + 30H + 30H + 30H + 30H + 30H + 30H + 30H + 30H + 30H + 03H =
4B9H