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Template:Networking rut manual modbus legacy (view source)
Revision as of 12:25, 28 December 2021
, 12:25, 28 December 2021no edit summary
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A Modbus <b>request</b> is a way of obtaining data from Modbus slaves. The master sends a request to a slave specifying the function code to be performed. The slave then sends the requested data back to the Modbus master. You can create a maximum of 64 request configurations for each slave device.
A Modbus <b>request</b> is a way of obtaining data from Modbus slaves. The master sends a request to a slave specifying the function code to be performed. The slave then sends the requested data back to the Modbus master. You can create a maximum of 64 request configurations for each slave device.
<span style="color:red"> <b>Note: </b></span>Modbus TCP Master uses <i>Register Number</i> instead of <i>Register Address</i> for pointing to a register. For example, to request the <i>Uptime</i> of a device, you must use <b>2</b> in the <i>First Register</i> field.
The figure below is an example of the Requests configuration section and the table below provides information contained in the fields of that section:
The figure below is an example of the Requests configuration section and the table below provides information contained in the fields of that section:
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A Modbus <b>request</b> is a way of obtaining data from Modbus slaves. The master sends a request to a slave specifying the function code to be performed. The slave then sends the requested data back to the Modbus master.
A Modbus <b>request</b> is a way of obtaining data from Modbus slaves. The master sends a request to a slave specifying the function code to be performed. The slave then sends the requested data back to the Modbus master.
<span style="color:red"> <b>Note: </b></span>Modbus Serial Master uses <i>Register Number</i> instead of <i>Register Address</i> for pointing to a register. For example, to request the <i>Uptime</i> of a device, you must use <b>2</b> in the <i>First Register</i> field.
The figure below is an example of the Requests configuration section and the table below provides information contained in the fields of that section:
The figure below is an example of the Requests configuration section and the table below provides information contained in the fields of that section:
===Request messages===
===Request messages===
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<span style="color:red"> <b>Note: </b></span>MQTT Gateway uses <i>Register Number</i> instead of <i>Register Address</i> for pointing to a register. For example, to request the <i>Uptime</i> of a device, you must use <b>2</b> in the <i>Register Number</i> field.
Modbus request data sent in the MQTT payload should be generated in accordance with the following format:
Modbus request data sent in the MQTT payload should be generated in accordance with the following format: