Rockwell Automation 20-750-CNETC PowerFlex Coaxial ControlNet Option Module - Manual (Page 63)

Rockwell Automation Publication 750COM-UM003B-EN-P - November 2012 63
Using the I/O Chapter 5
Using Logic Command/Status The Logic Command is a 32-bit word of control data produced by the controller
and consumed by the option module. The Logic Status is a 32-bit word of status
data produced by the option module and consumed by the controller.
When using a ControlLogix controller, the Logic Command word is always
DINT 0 in the output image and the Logic Status word is always:
• DINT 0 in the input image when using the drive Add-on Profile.
• DINT 1 in the input image when using the Generic Profile.
This manual contains the bit definitions for compatible products available at the
time of publication in
Appendix D , Logic Command/Status Words: PowerFlex
750-Series Drives.
Using Reference/Feedback The Reference is a 32-bit REAL (floating point) piece of control data produced
by the controller and consumed by the option module. The Feedback is a 32-bit
REAL (floating point) piece of status data produced by the option module and
consumed by the controller.
When using a ControlLogix controller, the 32-bit REAL Reference word is
always DINT 1 in the output image (see
Table 2 ) and the 32-bit REAL Feedback
word is always:
• DINT 1 in the input image when using the drive Add-on Profile.
• DINT 2 in the input image when using the Generic Profile.
When using a drive Add-on Profile, the Reference and Feedback are
automatically formatted properly and displayed as a controller tag. When using
the Generic Profile, the I/O image is integer-based and the Reference and
Feedback are floating point. Because of this, a COP (Copy) instruction or User
Defined Data Type (UDDT) is required to correctly write values to the
Reference and read values from the Feedback. See the ladder logic program
examples in
Figure 15 and Figure 16 .
The Reference and Feedback 32-bit REAL values represent drive speed. The
scaling for the speed Reference and Feedback is dependent on drive Parameter
300 - [Speed Units]. For example, if Parameter 300 is set to Hz, a 32-bit REAL
Reference value of ‘30.0’ would equal a Reference of 30.0 Hz. If Parameter 300 is
set to RPM, a 32-bit REAL Reference value of ‘1020.5’ would equal a Reference
of 1020.5 RPM. Note that the commanded maximum speed can never exceed the
value of drive Parameter 520 - [Max Fwd Speed].
Table 3 shows example
References and their results for a PowerFlex 750-Series drive that has its:
• Parameter 300 - [Speed Units] set to Hz.
• Parameter 37 - [Maximum Freq] set to 130 Hz.
• Parameter 520 - [Max Fwd Speed] set to 60 Hz.
TIP When using the drive Add-on Profile, the controller tags for Reference and
Feedback are automatically and properly formatted. This eliminates the need
for data conversion using COP (copy) instructions or a UDDT to copy the DINT
data into a REAL word.