Rockwell Automation VSM500 Integrated Drive/Motor DeviceNet Option Board - Manual (Page 41)

Using I/O Messaging 5-1
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5
Using I/O Messaging
This chapter provides information about using control I/O. It includes information on
understanding I/O messaging and assemblies, an example of I/O messaging, and an
example SLC ladder logic program.
Important: To use control I/O, you must have already configured the VSM500 unit
and DeviceNet option (refer to chapter 3) and scanner (refer to chapter 4).
5.1 Understanding I/O Messaging and Assemblies
On DeviceNet, I/O messaging, sometimes called implicit messaging, is used to
transfer the I/O data, which controls the VSM500 unit and its speed.
The control I/O messages that are transmitted between the scanner and VSM500 unit
depend on the output assembly and input assembly that you select. You can choose
between various input and output assemblies, thereby choosing the data format of the
control I/O messages. The assemblies that are supported are numbered and are part
of a DeviceNet defined “Motor Control Hierarchy.” This feature lets you use a VSM500
unit to replace motor starters or contactors on a network without the need to
reprogram the scanner.
You select the output assembly using parameter 107 [ OUTPUT ASSEMBLY ] and the
input assembly using parameter 108 [ INPUT ASSEMBLY ]. These parameters are
described in the parameter list in Appendix B (section B.3). Data formats for
assemblies are in Appendix C (section C.5).