| The Aerotech Ethernet/IP interface
enables AB PLCs (MicroLogix, CompactLogix, and ControlLogix)
to integrate directly with the Ensemble motion control solutions.
Motion can be directly programmed in the RSLogix 5000 environment
or separate programs can be written on the controller and
triggered from the AB PLC. Aerotech has two Ethernet/IP
interfaces: ASCII and Register. Choose the PLC, motion controller,
and Ethernet/IP interface that best fits your application
needs.
The Allen-Bradley code snippets provided here are written
in the graphical “relay ladder logic” syntax.
Allen-Bradley also supports function block and structured
text programming languages.
ASCII COMMAND INTERFACE
The ASCII command interface can be used to send ASCII text
strings to the Ensemble and perform a set of actions such
as commanding motion or retrieving diagnostic information.
Our vendor-specific EtherNet/IP ASCII command interface
object extends this functionality across
EtherNet/IP.
The power of the ASCII command interface lies in its simplicity
and ease of use. A text string is formed using an AeroBasic™
command, followed by an End-Of-String (EOS) character. ASCII
response data indicates whether or not the command was successfully
executed. An ACK character is sent to indicate success,
an NAK character is sent if there is a command error, and
a FAULT character is sent if there is a task error. For
commands that expect return data, the response character
is followed by the return data, which is terminated by the
EOS character. The EOS, ACK, NAK, and FAULT characters are
configurable via Ensemble drive parameters. To send the
ASCII command from the PLC (programmed using Rockwell RSLogix)
to the Ensemble, an MSG block is used (Figure 1). The EtherNet/IP
message can be easily configured from within the RSLogix
software as shown in Figure 2.
ASCII_Text_String (specified in the red box in Figure 2)
is an RSLogix “tag”. The value of this tag is
the ASCII command that will be sent to the Ensemble. The
example in Figure 3 shows the command “HOME X Y”
as it would be configured in RSLogix.
EtherNet/IPTM is a trademark
of ODVA.
CompactLogixTM and RSLogixTM are trademarks
of Allen-Bradley.
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When the MSG block is activated, the ASCII command is sent
to the Ensemble via the EtherNet/IP protocol. The Destination
field of the message configuration can be used to specify
a local tag for the ASCII command’s return data.
Ensemble Code Snippet (AeroBasic) for ASCII Interface
For this interface (see Figure 4), the user does not need
to write any AeroBasic code on the Ensemble. The Ensemble
automatically receives and processes the commands. This
functionality is built into our EtherNet/IP module.
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