The slave did not respond fast enough or not at all. This can happen after the connection has been interrupted. The slave has answered my incomplete packet. For example, it is possible that you have entered too many registers. Check the register address.Īt least one part of the data values used is invalid. The register is either write-protected or invalid. The Modbus register address used is not valid. Check if you are using the correct function code. The following table shows the most important error messages. The error codes correspond to the Modbus exception codes as specified in the Modbus specification. The error stays in this register until the value “1” is written manually into the Modbus register “Action_Status_Reset_”.
USE CLICK PLC AS MODBUS SERVER CODE
If an error occurs in a task, the error code is written to the Modbus register “Modbus_Action_Status_”. For each task there is a register for status and status reset. The Modbus master can handle up to 32 tasks. The configured device does not respond or you are using a register address which is not allowed by the slave (see note above)).Ĭheck that the IP address is correct and that the cables are plugged in correctly. The error stays in this register until the value “1” is written manually into the Modbus register “Master_Status_Reset”. If a communication error occurs, the error code is written to the Modbus register “Modbus_Master_Status”. The Modbus master has predefined Modbus registers for status messages. Select a format you want to continue working with.You can specify the format of the file and the filename.Įxport 01 creates a file that is suitable for use in logiCAD3.Įxport 02 creates an offset list which you can use as basic information for your own C-program. This activates the changes for the adapter.ĭo you want to continue using the settings in logiCAD3 or C?Ī window opens. You use address 30054 for this register when configuring a Modbus command. The addresses start at 0 according to the documentation. If the slave you want to use uses 0 as the first register address, you must add a 1 to the specified value during configuration.Įxample: The documentation for your slave states a register address 30053. Some manufacturers use 0 as the first register address for their products.Ĭheck how the addressing is specified at your slave. We use the first register address 1 for our products. Make sure that the different commands do not overlap. The variable name in the RevPi process image in which the first word or bit of the Modbus command is read or written.ĭepending on the selected function code, the dropdown menu offers you the appropriate target addresses of the process image for selection. The interval at which the command is sent (in milliseconds) Number of registers (or bits) that are read/written Please note the comment regarding the register address below this table!
You will find information on how the registers of the slave are assigned in the operating instructions of the slave. The Modbus register address or bit address of the data you want to access.
Read an whole 16-bit input/output register Modbus has function codes that allow access to data in a certain way. In this case it is recommended to set the value 255 (invalid).
USE CLICK PLC AS MODBUS SERVER MANUAL
Please refer to the instruction manual of your slave, if you have to set this address. This is where you can set the Modbus commands. Right-click on the Modbus TCP Master on the Configuration Board.This makes for instance sense if you want to implement 2 different controllers in the same network, which should not interfere with each other. The default value is “502”according to Modbus specification. We’ve already determined the values from the sensor’s instruction manual: In the “Value Editor” we define the settings for the TCP connection.Your Modbus-TCP Master will now appear on the far right of the Configuration Board. Hold down the left mouse button and drag the Modbus TCP Master to your RevPi Connect.Open the folder “Virtual Devices”in the device catalog.Click the start button behind the entry “PiCtory”.Enter the following command: “sudo revpi-config enable pimodbus-master”. Note!: You can also activate the Master function on the command line. Click “Enabled” in the Enable/Disable Modbus Master line.You can now see the current device status of your RevPi Connect. You can find it on the sticker on the side of your RevPi Connect.
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