Configuring Modbus TCP Request Settings
Original instructions
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Overview
Use the Request Setting page to configure scanner connection information for a remote Modbus TCP device.
To display this page, select a remote Modbus TCP device in the Device List node in the left pane of the Device Editor, then click on the Request Settings tab.
NOTE: Refer to the topic Configuring Properties in the Device Editor for instructions on how to edit properties.
Configuring the Request Settings Page
The Request Settings page includes the following settings:
Setting
Description
Connection Bit
The offset for both this connection’s health bit and control bit.
Unit ID
The number of the device, or module, that is the target of the connection. A value of:
  • 255 (the default) used to access the Ethernet communication module itself
  • 0...254 identifies the device number of the target device, behind a Modbus TCP to Modbus gateway
NOTE: When accessing data in the Ethernet communication module itself, use 255. When accessing data in the application running in the PLC, use a value from 0 to 254 (a value of 1 is recommended).
Health Timeout
The maximum allowed period, in milliseconds, between device responses, from 0 to 120000 ms, in intervals of 5 ms. When this setting is exceeded, the health timeout bit is set to 1.
Default = 1500 ms
Repetitive Rate
The rate at which data will be scanned, from 0 to 60000 ms, in intervals of 5 ms.
Default = 60 ms
RD Address
Address—from 0 to 65535—in the remote device of the first word from which the communication module reads data.
RD Length
The number of words in the remote device, from 0 to 125, that the communication module will read.
Last Value
The behavior of inputs in the application in the event communication is lost:
  • Hold Value (the default)
  • Set To Zero
WR Address
Address—from 0 to 65535—in the remote device of the first word to which the communication module writes data.
WR Length
The number of words in the remote device, from 0 to 120, that the communication module will write.
NOTE: For RD Address and WR Address, take into account the remote device address system and check you read or you write the right information, for instance Modicon Quantum addresses start from 1 whereas Modicon Premium addresses start from 0.