Omega A2400 - Manual (Page 28)

Command Set 4-7
Command Descriptions
All the commands may be used with normal addressing or Extended
Addressing unless otherwise noted. Commands that are exclusive to the
Extended Address mode are noted near the right hand margin. For example:
Closed Channel (CC) (Extended)
Closed Channel (CC) (Extended)
The Close Channel (CC) command is an Extended Address Mode com-
mand that is used to close the communications data channel in an A2400.
A closed communications channel will prevent the flow of serial data present
on the A2400’s RS-232 receive input onto RS-485 data lines. Assume
Extended Address ‘01’ and the factory installed ‘{‘ and ‘}’prompts are used:
Command: {01CC
Response: *
Command: }01CC
Response: *01CC11
Digital Output (DO)
The DO command controls digital output (DO0/ARTS pin) on the module
connector. The digital output allows the module to control an external circuit
under host command. The DO command requires an argument of two hex
characters.
The digital output is wired to the collector of a transistor in the module. The
collector is connected to +5Vdc through a 5.6k
Ω
pull up resistor. If the digital
output bit is set to ‘1’ the transistor is turned on and sinks current. Note that
when the digital output bit is set to ‘1’ the electrical output is near 0 volts. If
the digital output bit is set to ‘0’ the transistor is turned off and sinks no
current. See Figure 2.1 for details.
Assume that you wish to turn the digital output bit on (sinking current). Set
data bit 0 to ‘1’. Since the module has only one digital output, all the other
bits are ‘don’t cares’. For example, this command will turn the output ‘on’:
Command: $1DO01
Response: *
Command: #1DO01
Response: *1DO014F