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MVI56-MCM
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ControlLogix Platform
Reference
Modbus Communication Module
Page 114 of 159
ProSoft Technology, Inc.
July 24, 2008
Register Content
Description
5028
Holding Reg Offset
This parameter specifies the offset address in the
internal Modbus database that is to be used with
network requests for Modbus function 3, 6, or 16
commands. For example, if a value of 50 is
entered, a request for address 0 will correspond to
the register 50 in the database.
5029 Command
Count
This parameter specifies the number of commands
to be processed by the Modbus master port.
5030
Minimum Command
Delay
This parameter specifies the number of
milliseconds to wait between issuing each
command. This delay value is not applied to
retries.
5031
Command Error Pointer This parameter sets the address in the internal
Modbus database where the command error will be
placed. If the value is set to -1, the data will not be
transferred to the database. The valid range of
values for this parameter is -1 to 4899.
5032 Response
Timeout
This parameter represents the message response
timeout period in 1-millisecond increments. This is
the time that a port configured as a master will wait
before re-transmitting a command if no response is
received from the addressed slave. The value is
set depending upon the communication network
used and the expected response time of the
slowest device on the network.
5033 Retry
Count
This parameter specifies the number of times a
command will be retried if it fails. If the master port
does not receive a response after the last retry, the
slave devices communication will be suspended on
the port for Error Delay Counter scans.
5034
Error Delay Counter
This parameter specifies the number of polls to
skip on the slave before trying to re-establish
communications. After the slave fails to respond,
the master will skip commands to be sent to the
slave the number of times entered in this
parameter.
5035 to 5039
Spare
Reserved for future use.
8.5.3 Port 2 Setup
Register Content
Description
5040 Enable This parameter defines if this Modbus port will be
used. If the parameter is set to 0, the port is
disabled. A value of 1 enables the port.
5041 Type
This parameter specifies if the port will emulate a
Modbus master device (0), a Modbus slave device
without pass-through (1), a Modbus slave device
with unformatted pass-through (2), a Modbus slave
device with formatted pass-through and data
swapping (3), or a Modbus slave device with
formatted pass-through and no data swapping (4).