The integrated test function can be used to check configured Modbus TCP devices and their data points.
This makes it possible to determine whether a Modbus TCP device is reachable on the network and whether the configured data points return the expected values. For example, the register type, register address, and data type can be verified directly.
The test function helps identify configuration errors at an early stage and allows settings to be checked before they are permanently applied.
Note
Data point values can only be read using Refresh Status if the associated Modbus TCP device is connected.
A Modbus TCP device is considered connected if at least one of its data points is used in an active logic group.
Function
Two buttons are available for the test function:
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Refresh Status
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Test Changes
Depending on the current configuration state, only one of the two buttons is active at a time.
Refresh Status
Refresh Status checks the currently saved configuration.
This can be used to:
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check the connection status of the Modbus TCP device,
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verify whether the device is reachable,
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read the current values of already configured data points.
Test Changes
Test Changes can be used to check configuration changes that have not yet been saved.
This allows changes to the following parameters, for example, to be tested immediately:
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IP address or hostname
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port
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Unit ID
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register type
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register address
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data type
The modified configuration does not need to be saved first or used in an active logic group.
Note
Test Changes is particularly useful for checking new or modified settings before they are applied to the working copy using Save.
Testing a Modbus TCP Device
This function can be used to check the connection and reachability of a configured Modbus TCP device.
The following information is displayed, among other things:
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whether the device is reachable on the network,
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whether the Modbus TCP device is currently connected,
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how many data points are configured for the device.
The status can be checked again at any time using Refresh Status.
If a test is unsuccessful, the connection settings can be adjusted and checked again using Test Changes without having to save the modified configuration first.
Querying Modbus TCP Data Points
This function can be used to query the current values of the data points configured for a Modbus TCP device.
In addition to the returned value, this allows you to verify whether the configuration of the respective data point matches the connected Modbus device.
This applies in particular to:
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Unit ID
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register type
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register address
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data type
Using Refresh Status, the values can be queried again based on the currently saved configuration.
If the expected value is not returned or the query fails, the corresponding parameters can be changed and then tested again immediately using Test Changes.
This allows different settings to be tested without having to save the Modbus TCP configuration after each change.
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