ProSoft Technology MVI56E-MNETR - Manual (Page 116)

MVI56E-MNETR ♦ ControlLogix Platform Reference
Modbus TCP/IP Interface Module with Reduced Data Block User Manual
Page 116 of 153
ProSoft Technology, Inc.
August 31, 2009
2 When configured, the client driver begins transmitting read and/or write
commands to the other nodes on the network. If writing data to another node,
the data for the write command is obtained from the module's internal
database to build the command.
3 Presuming successful processing by the node specified in the command, a
response message is received into the client driver for processing.
4 Data received from the node on the network is passed into the module's
internal database, assuming a read command.
5 Status data is returned to the processor for the client and a Command List
error table can be established in the module's internal database.
Client Command List
In order for the client to function, the module's Client Command List must be
defined. This list contains up to 100 individual entries, with each entry containing
the information required to construct a valid command. This includes the
following:
ƒ Command enable mode
o (0) disabled
o
(1) continuous
o
(2) conditional
ƒ IP address and service port to connect to on the remote server
ƒ Slave
Node Address
ƒ Command Type - Read or Write up to 100 words per command
ƒ Database Source and Destination Register Address - Determines where data
will be placed and/or obtained
ƒ Count - Select the number of words to be transferred - 1 to 100
ƒ Poll Delay - 1/10
th seconds
Client Command Errors
You can use the MNET 0 Client Command Error Pointer in the MNET.CFG file to
set the database offset register where all command error codes will be stored.
This means that the first register refers to command 1 and so on.
Offset Description
1 Command 1 Error
2 Command 2 Error
3 Command 3 Error
… ….
… …
For every command that has an error, the module automatically sets the poll
delay parameter to 30 seconds. This instructs the module to wait 30 seconds
until it attempts to issue the command again.
As the list is read in from the configuration file and as the commands are
processed, an error value is maintained in the module for each command. This
error list can be transferred to the processor. The errors generated by the module
are displayed in the following table.