Rockwell Automation 2711 PANELBUILDER SOFTWARE USER MANUAL - Manual (Page 233)

Information and Alarm Windows
Chapter 7
7-25
if Binary is specified, the address assignment will be a contiguous
bit string containing from 1 to 16 bits, depending on the number of
alarm messages defined. For example, for 256 alarm messages,
you would use 8 bits.
if BCD is specified, the address assignment will be a contiguous
bit string of 4, 8 or 12 bits (that is, 1, 2, or 3 digits), depending on
the number of messages defined. For example, for 256 alarm
messages, you would use 12 bits.
if Bit is specified, the address assignment will be a contiguous bit
string containing from 1 to 496 bits, depending on the number of
messages defined. For example, for 256 alarm messages, you
would use 256 bits.
IMPORTANT: See the following section on Address Assignment and
PLC Alarm Message Triggering for more information.
Update Address updates the application file with the values entered for
the Data Type through to the Number of Bits. The new address is
displayed at the top of the menu. If you make a mistake entering a new
address, an error message will appear when you choose Update Address.
View Address Map shows you the address map of the bits allocated so
far for all the objects, windows and PLC Control Options.
Delete Address allows you to remove the existing address from the file.
Quit closes the Window Control Address and returns you to the Alarm
Window menu.
Address Assignment and PLC Alarm Message Triggering
How the PLC controller triggers messages depends on which data type is
selected.
Binary Data Type
If you specify Binary, the address assignment will be a contiguous bit
string containing from 1 to 16 bits. The bit string can be positioned
anywhere within the same PLC word (even crossing word boundaries) by
designating the desired start bit (the default is zero which is the typical
choice).