B&B Electronics RS-232 Digital Relay I/O 232DRIO User Manual
Page 14
12 232DRIO-0308
Manual
B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 433-5104
Example 3.1
Set Output Lines
Data
Byte Relays
Binary Decimal
Hex Relay
#2
Relay #1
XXXXXX00
0
0
de-energized de-energized
XXXXXX01
1
1
de-energized energized
XXXXXX10
2
2
energized
de-energized
XXXXXX11
3
3
energized energized
Symbol: X don’t cares (default setting should all be “0”)
To energize the relays, the corresponding bit of the data byte must
be set high. Conversely, to de-energize the relays the
corresponding bit of the data byte must be set low.
(00000011, 3 in decimal, 3 in hex: energized both relay #1 and #2)
Example 3.2
Read I/O Lines
Data
Byte
Returned
Status
Binary Dec Hex ASCII Input #1 Relay
#2
Relay #1
00000000
0
00
NUL low
de-energ. de-energ.
00000001
1 01
SOH low
de-energ. energ.
00000010 2 02
STX low
energ.
de-energ.
00000011
3
03
ETX low
energ.
energ.
00000100
4
04
EOT high
de-energ. de-energ.
00000101
5
05
ENQ high
de-energ. energ.
00000110
6
06
ACK high
energ.
de-energ.
00000111
7 07
BEL high
energ.
energ.
Notice that the returned data byte starts at address 00000000 in
binary, 0 in dec., 0 in hex., or NUL in ASCII. From left to right (msb
to lsb), the first five bits are really XXXXX “don’t cares” but are
defaulted as “00000”. The remaining three bits represent input #1,
relay #2, and relay#1, respectively. A “1” or a HIGH represents relay
energized/input present, and a “0” or a LOW represents relay de-
energized/input absent.