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 |
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Response: | *31070000 | (Factory |
Command: | $1WE |
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Response: | * |
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Command: | $1SU31070030 |
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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.