<< Page 1

REGISTER INTERFACE
Our vendor-specific EtherNet/IP register interface object allows the Ensemble’s built-in integer and double registers to be accessed via EtherNet/IP. This provides a flexible, general-purpose interface to the Ensemble that can be adapted to many different applications. Data consistency is guaranteed internally, so there is no need for concern when accessing these registers simultaneously via EtherNet/IP and AeroBASIC programs on the controller. The Rockwell software is configured in very much the same way as the ASCII command interface. In this case, the message source (shown in red in Figure 5)
is a data array.

The message configuration in Figure 5 is for the “Write Single Register” service. That service requires two pieces of data: the number of the register to write, and the value to be written. Therefore, we configure the message source tag as shown in Figure 6.



The value 100 is the register to write to, and the value to be written is 7. When the MSG block is activated, the register query is sent to the Ensemble via the EtherNet/IP protocol. As you can see, this is a straightforward data interface from the PLC to the Ensemble. In addition to writing a single register, the interface also supports writing multiple registers in one message and reading single or multiple registers. This example was interfacing with an integer (32-bit) register, but the interface supports the same functionality with double-precision (64-bit) floating point values.

Ensemble Code Snippet (AeroBASIC) for Register Interface
To make use of the data that is being transferred to and from the PLC, the user can write an AeroBASIC program to respond to incoming register transfers, as well as write outbound register data. This combination of EtherNet/IP communication with the power and flexibility of AeroBASIC allows for the implementation of many unique applications. For example, the following AeroBASIC code snippet shows how the register interface can be used to control the Ensemble timebase value (set by the AeroBASIC TimeScale command).

HEADER
     ' The PLC writes timebase values to IntegerRegister 101
     Define timebaseRegisterIndex 101
END HEADER

DECLARATIONS
     ' Declare a global variable named "timebase"
      Global timebase as Integer
END DECLARATIONS

PROGRAM
     ' initialize the timebase register to 100% speed
      RegS IntegerRegisters,  timebaseRegisterIndex, 100

      ' ... do work in AeroBASIC ...

      ' Change timebase to value sent from PLC
        Call GetTimebase()
        TimeScale timebase

       ' ... continue working ...
END PROGRAM

FUNCTION GetTimebase() as void
      ' Read the value from IntegerRegister 101 into the variable "timebase"
      timebase = RegS(IntegerRegisters, timebaseRegisterIndex)
END FUNCTION