Omega A2400 User Manual
Page 55
Extended Addressing 9-3
When the system is initially powered up, the A2400’s are set to the Close
Channel condition. This means that no data received by the radio modems
will pass to the RS-485 bus at either site. In order to communicate to the
modules, one of the A2400’s must be set to the Open Channel condition:
Command:
{01OC
Response:
*
This command orders the A2400 address ‘01’ to open the ‘data gate’
between the radio modem and the two-module string on the RS-485 bus.
Now the host computer may communicate to the modules in a normal
fashion:
Command:
$1RD
Response:
*+00100.00
(typical)
Command:
$2RD
Response:
*+00123.45
(typical)
Note that A2400 address ‘02’ is still in a Close Channel state. No data
received by this A2400 will be allowed to pass to the RS-485 bus. Therefore
there is no conflict between the two module strings containing identical
addresses. Only one A2400 is allowed to be in an Open Channel state at any
time.
To access the module string located at A2400 address ‘02’, first close the
channel at A2400 #01:
Command:
{01CC
Response:
*
Now open the ‘data gate’ at A2400 #02:
Command:
{02OC
Response:
*
Any commands from the host are now directed through A2400 #02:
Command:
$1RD
Response:
*+00000.00
Command:
$2RD
Response:
*00005.00