Omega A2400 - Manual (Page 66)

Transparent Mode 10-7
Figure 10.5 shows an application where the user was able to add a back-up
or secondary control supervision using the A2400 modules. The original
installation of the flow computers and PLC’s were controlled by the control
station using Modbus protocol with RS-485. The user was able to use A2400
modules on the RS232 ports of the devices and establish a second control
loop The flow computers and PLC’s had addressing capability.
TheThe transparent mode can only be enabled or disabled via the module’s
setup message using the SetUp command. The transparent mode can be
enabled while the module is operating in either the normal or the extended
addressing mode.
The TRANSPARENT mode has to be set up manually or with the utility
software.
Command: $1RS
Response: *31070000 (Factory set-up)
Command: $1WE
Response: *
Command: $1SU31070030
Disables Character Filter and enables TRANSPARENT mode. (Bit 4 & 5 of
Byte 4 set to 1)
Disabling the transparent mode requires that the A2400 module first be put
into the Default Mode (connecting the Default* pin to ground). In Default
Mode the module is put in a known communication setup: 300 baud, no
parity, any address is recognized. Once communications is established the
module’s Setup Message can be changed. The transparent mode is
disabled by changing bit 5 in byte 4 to a 0. (Example: $1SU31070000) or use
SETUP in the utility software.