B&B Electronics RS-485 manual Syntax, Reading A/D Channels Command, Equivalent Values

The decimal and hexadecimal equivalents of some ASCII characters are shown in Table 3.2. Notice that the ASCII representation of the character “0” does not have a value of 0. Refer to Appendix C for more ASCII, decimal, and hexadecimal equivalents.

Table 3.2 - Equivalent Values

ASCII	Decimal	Hexadecimal
!	33	21h
0	48	30h
A	65	41h
D	68	44h
O	79	4Fh
R	82	52h
S	83	53h
NUL	0	0h
SOH	1	1h
STX	2	2h
ETX	3	3h
EOT	4	4h
ENQ	5	5h
ACK	6	6h
BEL	7	7h

Syntax

The command string consists of four bytes. The first byte is the start of message byte. The start of message byte is always the “!” character. The second byte is the address byte. This byte allows each unit to have a unique address. The factory default address is the ASCII “0” (zero) character. The next two bytes are the command characters. These bytes are used to specify which command the module will execute. The read A/D and digital I/O commands require an additional data byte.

Command Syntax: !		_	_	_
				Data Byte
			2nd Command Byte
		1stCommand Byte
	Address Byte
Start of Message Byte

Reading A/D Channels Command

485SDA103798 Manual 13

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