User manual

IEC61131 User and Reference Manual
April 22, 2008
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 To close the dialog, without making a selection click the Cancel button.
General Parameters
When Modbus ASCII is selected for configuration the Modbus ASCII Configuration dialog is
opened with the General tab selected as shown below.
The Modbus Communication Settings grouping contains Modbus specific communication
settings including the addressing mode, the station address, the timeout interval as well as
the number of attempts.
The Addressing parameter selects standard or extended Modbus addressing. Standard
addressing allows 255 stations and is compatible with standard Modbus devices. Extended
addressing allows 65534 stations, with stations 1 to 254 compatible with standard Modbus
devices. The default is Standard.
The Station parameter sets the target station number. The valid range is 1 to 255 if standard
addressing is used, and 1 to 65534 if extended addressing is used. The default is 1.
The Timeout parameter sets the length of time, in seconds, to wait for a response from the
controller before retrying (see Attempts), or ultimately failing. Valid entries are 1 to 255. The
default is 3.
The Attempts parameter sets number of times to send a command to the controller before
giving up and reporting this failure to the host application. Valid entries are 1 to 20. The
default is 3.