Devices in catalog

Specific devices (like custom devices) have a different interface from the Generic Modbus Slave; selecting a device node from the project tree (previously added from the Catalog window), will display the following inside the main window: The General tab lets you set:

• Name: name of the slave node.
• IP address: IP address of the slave node.
• Modbus address: MODBUS address of slave node inside the Network.
• Node number: value used by diagnostics tools to identify the slave node.
• TimeOut: time (ms) waited before the operation is considered failed (default = 1000 ms)
• Wait before send: time (ms) waited before executing a new operation; this value is added to the polling time of the parameter. (Default = 0 ms).

The Parameterization tab lets you define a series of Modbus objects sent to the slave node at each PLC restart.The list of objects to be sent is built with the Add and Remove buttons that appear on the Tab. The objects shown in the window that appears after the Add button is pushed are all (and only) RW parameters contained in the device Modbus dictionary.You can set the order for sending parameters to the slave node by using the Up and Down buttons. Once an object (a row) is added, you have to set:

• Value: value to be assigned to Modbus object
• TimeOut: time (ms) waited before the operation is considered failed (default = 200 ms)

The Input tab lets you define (with the Add and Remove buttons) which and how many parameters will be read by the device.The window that appears when the Add button is pushed shows all of the available objects in the device Modbus dictionary (both RO and RW).You can set the order for reading parameters from the slave node by using the Up and Down buttons. You have to assign a variable to each line inserted by using one of the modes described below:

• Use the Assign button, click one of the Automatic variables (the type depends on the contents of the Type column) previously declared on the PLC. The variable will no longer appear in the Automatic variables list but will be mapped in the appropriate datablock.
• Directly declare a variable in the Label column (the type depends on the contents of the Type column); the variable will be created and mapped in the appropriate datablock.

You can also set the Polling time parameter to define the interval in milliseconds between two executions of MODBUS command; if set to 0, the time between two commands execution depends on the PLC idleIf the listed objects have:

• Contiguous Addresses
• Identical Polling time
• Homogeneous Type: USINT, BYTE, INT, UINT, WORD, DINT, UDINT, DWORD and REAL are homogeneous with regard to Modbus because they are all seen as one or more registers.

They will be grouped in a single Modbus request, subject to the maximum number of consecutive objects (bits or registers) that can be exchanged with the device in a single request.The Output tab lets you define (with the Add and Remove buttons) which and how many parameters will be written on the device.The objects shown in the window that appears after the Add button is pushed are all (and only) RW objects contained in the device Modbus dictionary.You can set the order for writing these parameters on the slave node by using the Up and Down buttons. You have to assign a variable to each line inserted by using one of the modes described below:

• Use the Assign button, click one of the Automatic variables (the type depends on the contents of the Type column) previously declared on the PLC. The variable will no longer appear in the Automatic variables list but will be mapped in the appropriate datablock.
• Directly declare a variable in the Label column (the type depends on the contents of the Type column); the variable will be created and mapped in the appropriate datablock.

You can also set the Polling time parameter to define the interval in milliseconds between two executions of MODBUS command; if set to 0, the time between two commands execution depends on the PLC idle.If the listed objects have:

• Contiguous Addresses
• Identical Polling time
• Homogeneous Type: USINT, BYTE, INT, UINT, WORD, DINT, UDINT, DWORD and REAL are homogeneous with regard to Modbus because they are all seen as one or more registers.

They will be grouped in a single Modbus request, subject to the maximum number of consecutive objects (bits or registers) that can be exchanged with the device in a single request.