B&B Electronics 485DSS manual OFF Command, Status Request Command

If you were writing a program in BASIC to turn on address 10 decimal (0A hexadecimal) you might form a string like this:

DSS0AON$ = CHR$(19) + "0" + "A" + CHR$(1)

You could then send DSS0AON$ to select 485DSS address 10 (0A hex). Use similar strings for turning on the other 485DSS's.

OFF Command

This command turns off all 485DSS's on the network and lowers the RTS output handshake line on pin 4 of the DB25 connector. The command string consists of all non-printable ASCII characters. This command uses two broadcast characters "DC2" (decimal 18) in the address field. Sending this command before sending a command that has a specific address (address characters are printable) keeps the RS-232 device from outputting any printable characters.

NOTE: This command permits only the use of the broadcast characters in the address field.

Command character: EOT (decimal 4)

Example 1: Turn off all the 485DSS's on the network.

HOST transmits: Xoff	DC2 DC2		EOT
( 19	18	18	4 decimal)
( 13	12	12	4 hex)

The turn off string in BASIC might look like this:

DSSOFF$ = CHR$(19) + CHR$(18) + CHR$(18) + CHR$(4)

You could then send DSSOFF$ to turn off all 485DSS's.

ALL data and control characters are passed through the 485DSS after it has been selected.

STATUS REQUEST Command

The Status Request command requests the status of an individual 485DSS or the status of all 485DSS's on the network. This command enables the Host computer to determine from each reply message received if the RS-232 device is requesting access to the network and if it has access to the network. By using this command the Host has the ability to prioritize all the 485DSS's on the network. A specific address in the address field specifies a response from an individual 485DSS. Placing broadcast characters

485DSS3298 Manual 11

B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350

PH (815) 433-5100 -- FAX (815) 434-7094