ModbusPLCRS connection

The ModbusPLCRS connection is added to the Communication Driver hierarchy from the ModbusBridge branch.

Add a ModbusPLCRS connection to your MBTCP hierarchy

1. Right-click on your ModbusBridge branch, and select Add ModbusPLCRS Connection from the shortcut menu.

   • A new ModbusPLCRS object is created as a node in the hierarchy tree.

   • Default name is New_ModbusPLCRS_000.

     Note: You can add up to 247 objects of this type to the hierarchy.

2. Rename as appropriate.

   • The New_ModbusPLCRS_000 Parameters configuration view is displayed.

     

This configuration view has 13 configurable elements.

• PLC unit ID: Enter the PLC unit ID.
  The Bridge's internal configuration contains a UnitID parameter which can be set to override the Unit_ID address received in the message from the server. In other words, when the Unit_ID box is 0 (zero) the bridge routes the message to its configured Slave device. If the server's Unit_ID is set to 0 (zero), the message will be delivered to the Slave device whose address is defined in the UnitID box of the Bridge. If the server's Unit_ID is set to a non-zero value (range 1…255), the message will be delivered to the Slave device at that numerical address, regardless of the contents of the UnitID box in the Bridge.

  • The minimum value is 0 (zero).

  • The maximum value is 255.

  • The default value is 1 (one).

• Reply timeout (sec): Enter the amount of time the server will wait for an acknowledgment.

  • The minimum value is 1 (one).

  • The maximum value is 60.

  • The default value is 3 (three).

• Use Concept data structures (Longs): Select to read data from the PLC in concept data structure format for Long item types. If checked, the Communication Driver will process the data in the same register order as the Concept programming software.

  • Checked – selected (Default)

  • Not checked – not selected

• Use Concept data structures (Reals): Select to read data from the PLC in concept data structure format for Real item types. If checked, the Communication Driver will process the data in the same register order as the Concept programming software.

  • Checked – selected (Default)

  • Not checked – not selected

• Support multiple coil write: Select for the PLC to write to multiple coils in one message. If not selected, the PLC will write to a single coil in one message.

  • Checked – selected (Default)

  • Not checked – not selected

• Support multiple register write: Select for the PLC to write to multiple registers in one message. If not selected, the PLC will write to a single register in one message.

  • Checked – selected (Default)

  • Not checked – not selected

    Note: When the Support Multiple Register Write Parameter is not selected in the Generic PLC configuration, it implies that the PLC does not support multiple register writes and the server will only write single registers to the PLC.
    This means that items that contain more than one register cannot be written either. For example, items such as 4xxxxx L, 4xxxxx I, 4xxxxx U, 4xxxxx F, 4xxxxx-4xxxxx M, 5 HRL, 5 HRF, 5 PV, 5 HRU, and 4xxxxx-4xxxxx cannot be written. When you try to write to the PLC with this parameter not selected, the following error message will be logged to the logger, "Cannot write to multiple register item: 4xxxxx L on Node: TCPPort.GenPLC. The PLC configurable parameter Support Multiple Register Write is not checked."

• Use Zero Based Addressing: Select to choose 0-based addressing.

  • Checked – selected, use 0-based addressing

  • Unchecked – not selected, use 1-based addressing (Default)

• Swap bytes: Select to swap bytes in PLC register for 16-bit, 32-bit, and 64-bit signed and unsigned Integer, Float, and Double data types on data read and data poked.

  • Checked - selected (Default)

  • Not checked - not selected

• Swap string bytes: Select to swap bytes in PLC register for String data type on data read and data poked.

  • Checked - selected (Default)

  • Not checked - not selected

• Not checked - not selected the bit order entered into the PLC. There are four bit order formats available for selection.

  • B1 B2 … B16: (Default) Bit order is left to right (MSB = Bit 1; LSB = Bit 16)

  • B16 B15 … B1: Bit order is right to left (MSB = Bit 16; LSB = Bit 1)

  • B0 B1 … B15: Bit order is left to right (MSB = Bit 0; LSB = Bit 15)

  • B15 B14 … B0: Bit order is right to left (MSB = Bit 15; LSB = Bit 0)

• Register Order: The order of the PLC memory registers written to and read from, used to support 64-bit data types.

  • Order 1: R1 R2 R3 R4 (Default)

  • Order 2: R2 R1 R4 R3

  • Order 3: R3 R4 R1 R2

  • Order 4: R4 R3 R2 R1

    where R1, R2, R3, and R4 are the relative register addresses in the PLC.

• Register size (digits): Select the correct register size for addressing the PLC.

  • 4-digit is used for addressing the Modbus Generic 4-Digit PLCs.

  • 5-digit applies to the Modbus Generic 5-Digit PLCs.

  • 6-digit is used for addressing the Modbus Generic 6-Digit PLCs (default).

    Note: The selection for the Register size determines the maximum address range. They are changeable as in other supported PLCs listed in Supported MBTCP OI server hardware and firmware.
    For 4-digit, the maximum value is 999; for 5-digit, the maximum value is 9999; for 6-digit, the maximum value is 65536 (default).

• String variable style: PLC string-data format. Select the option for the style used by the device to store strings in its registers.

  • Full length (space padded) (Default)

  • C style (null terminated)

  • Pascal style (includes length specifier)

• Register type: Select either Binary or BCD for the register type being used.

  • Binary (Default)

  • BCD

• Block I/O size: This Block I/O Sizes box contains four sub-elements. The Communication Driver uses Block I/O Sizes to maximize data throughput. The MBTCP Communication Driver uses a 256-byte buffer to read or write data to the PLC. The maximum value is the maximum number of registers that can be read or written from/to the PLC in one command.

  Element	Description	Minimum Value	Maximum Value
  Discrete input/coil read	Enter the maximum number of discrete inputs or coils to read at one time.	Min = 1 (one)	Max = 1976 (Default)
  Coil write	Enter the maximum number of coils to write at one time.	Min = 1 (one)	Max = 800 (Default)
  Register read	Enter the maximum number of extended registers to read at one time.	Min = 1 (one)	Max = 122 (Default)
  Register write	Enter the maximum number of holding registers to write at one time.	Min = 1 (one)	Max = 100 (Default)

The logical endpoint for each branch of the MBTCP hierarchy tree is a hardware device (PLC).

Note: In order to use the Communication Driver, you must activate it. See the OI Server Manager documentation for information about how to activate and deactivate the Communication Driver.