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Reference MVI56-MCM
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ControlLogix Platform
Modbus Communication Module
ProSoft Technology, Inc.
Page 105 of 159
July 24, 2008
Transferring the Command Error List to the Processor
You can transfer the command error list to the processor from the module
database. To place the table in the database, set the Command Error Pointer
(MCM.Port1.CmdErrPtr) parameter to the database location desired.
In the sample ladder, the MCM.Port1.CmdErrPtr tag is set to a value of 1100.
This will cause the error value of command 0 to be placed at database address
1100. Each command error value occupies one database word. The error value
for command 1 will be in location 1101 and the remaining values in consecutive
database locations.
To transfer this table to the processor, refer to Command Error Codes. Make
sure that the Command Error table is in the database area covered by the Read
Data (MCM.ModDef.ReadStartReg and MCM.ModDef.ReadRegCnt).
8.3 Cable
Connections
The application ports on the MVI56-MCM module support RS-232, RS-422, and
RS-485 interfaces. Please inspect the module to ensure that the jumpers are set
correctly to correspond with the type of interface you are using.
Note: When using RS-232 with radio modem applications, some radios or modems require
hardware handshaking (control and monitoring of modem signal lines). Enable this in the
configuration of the module by setting the UseCTS parameter to 1.
8.3.1 RS-232
Configuration/Debug Port
This port is physically an RJ45 connection. An RJ45 to DB-9 adapter cable is
included with the module. This port permits a PC based terminal emulation
program to view configuration and status data in the module and to control the
module. The cable for communications on this port is shown in the following
diagram:
Disabling the RSLinx Driver for the Com Port on the PC
The communication port driver in RSLinx can occasionally prevent other
applications from using the PC's COM port. If you are not able to connect to the
module's configuration/debug port using ProSoft Configuration Builder (PCB),
HyperTerminal or another terminal emulator, follow these steps to disable the
RSLinx Driver.