Data Messaging-Application Considerations - Allen-Bradley Powermonitor 3000 User Manual

4-24 Communications
Data Messaging-
Application Considerations
Publication 1404-UM001D-EN-E - October 2004
I/O Type Communications
Powermonitor 3000 units with optional Remote I/O, EtherNet/IP
(Series B) and DeviceNet communications provide I/O type
messaging.
Remote I/O units emulate a logical quarter rack on the I/O channel.
The corresponding, two-word output and input image table elements
are automatically scanned by the I/O scanner, and the data points
they contain are available for use in the logic program of the
controller associated with the I/O scanner.
In DeviceNet units, Instances 1 and 2 comprise the DeviceNet polled,
change-of-state or cyclic connections. The default input table contains
6 integer typed elements and the output table contains two integer
typed elements. You may configure instance 1. Refer to the
User-configured I/O table discussion below.
In EtherNet/IP (Series B) units, Instances 1 and 2 comprise the
Class 1 connection. As in DeviceNet units, Instance 1 contains 6
integer elements of input data and Instance 2 contains 2 integer
elements of output data. You may configure Instance 1. Series A
Ethernet units do not support a Class 1 (I/O) connection.
Refer to Table A.2 Remote I/O, DeviceNet, EtherNet/IP and
ControlNet I/O Messaging on page A-4 for the content and format of
the I/O messaging data tables.
The Powermonitor 3000 supports a number of different
communications networks and protocols. Each of these has unique
characteristics and methods. The information in this section is
provided to assist you in designing and implementing data messaging
with the Powermonitor 3000 by discussing in detail the unique
properties of the communications options. Refer also to the Sample
ladder diagrams in Appendix C.
Serial Communications Options
The native RS-485 and optional RS-232 communications ports provide
basic serial asynchronous communications capabilities. Both the
RS-485 and optional RS-232 ports may be selected as Allen-Bradley
DF1 half-duplex slave, Modbus RTU slave or auto-sense, which selects
the protocol based on detection of incoming packets. Powermonitor
3000 units with master module firmware earlier than version 2.5x
support only DF1.