B&B Electronics 485DSS - Manual (Page 14)

10 485DSS-0308 Manual
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91 792444 – Fax +353 91 792445
The Command String
All Command Strings consist of four ASCII characters. The first
character is the start of message character, "X-off" (decimal 19).
The second and third characters represent the hexadecimal address
of an individual 485DSS. The address range is from 0 to 255 (HEX
"00" to "FF"). Some commands require the use of the broadcast
character "DC2" (decimal 18) as the second and third characters in
the command. The fourth character is the command character.
ON Command
This command turns on an individual 485DSS and asserts the
RTS output handshake line on pin 4 of the DB25 connector. This
command allows the RS-232 device connected to the 485DSS to
access the RS-485 network. The address field in the command
string specifies which 485DSS is to turn on. All other 485DSS's on
the network will turn off if the address field does not match their
address setting.
Command character: SOH (decimal 1)
Example 1: To turn on the 485DSS set to address 15 decimal (0F
hex).
HOST transmits: Xoff “0” “F” SOH
( 19 48 70 1 decimal)
( 13 30 46 1 hex)
Example 2: To turn on the 485DSS set to address 33 decimal (21
hex).
HOST transmits: Xoff “2” “1” SOH
( 19 50 49 1 decimal)
( 13 32 31 1 hex)
Command Syntax: X-off ____ ____ ____
| | | |
| | | Command character.
| | Least signf. address character.
| Most signf. address character.
Start of message character.