The Aerotech Ethernet/IP interface
enables AB PLCs (MicroLogix, CompactLogix, and ControlLogix) to
integrate directly with the Soloist motion control solution. 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 Soloist 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 Soloist drive parameters.
To send the ASCII command from the PLC (programmed using Rockwell
RSLogix) to the Soloist, 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 Soloist. The example in Figure
3 shows the command “HOME” as it would be configured
in RSLogix.
EtherNet/IPTM is a trademark of ODVA.
CompactLogixTM and RSLogixTM are trademarks
of Allen-Bradley. |
When the MSG block is activated, the ASCII command is sent to
the Soloist 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.
Soloist Code Snippet (AeroBASIC) for ASCII Interface
For this interface (see Figure 4), the user does not need to write
any AeroBASIC code on the Soloist. The Soloist automatically receives
and processes the commands. This functionality is built into our
EtherNet/IP module.
|
