Rockwell Automation FactoryTalk View Machine Edition Users Guide - Manual (Page 133)

9 • Set up alarms
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The tag is currently generating alarms at bit positions 2, 6, 12, 21, 22, 26, and 30.
To set up alarms for this array tag:
1. Create an alarm trigger for the array tag. Use the Bit trigger type.
You must use a direct reference for the array tag. The tag uses the Integer data type (16
bits per element). Append L2 to the tag’s starting address to indicate that the trigger
will monitor 2 tag elements (32 bits), as follows:
{::[PLC5]N7:0,L2}
PLC5 is the RSLinx Enterprise device shortcut name. The two colons at the beginning
are necessary when the tag reference contains a colon.
2. Specify trigger values and alarm messages for the alarm trigger. Each trigger value
corresponds to a bit position (not a bit address).
The Least Significant Bit (LSBit) trigger type
Use the Least Significant Bit trigger type to generate alarm messages based on a priority
sequence that is determined by bit position. You can assign an array tag (consisting of up
to 1,024 bits) to the trigger connection. When multiple bits in the array change from 0
to 1, only the alarm with the lowest bit position is generated.
Example: Trigger values using least significant bits
This example shows how to use the Least Significant Bit trigger type to prioritize which
alarm is generated when multiple alarm conditions occur.
In this example, a programmable controller monitors a motor’s power, manual stop, and
overload status. The diagram indicates the location of sensors that are linked to an array
tag in the programmable controller.
Bit in the array
(bit address)
Bit position Trigger value Message
00 1 1 Line 1: Conveyor has stopped.
01 2 2 Line 1: Power failure.
02 3 3 Line 2: Conveyor has stopped.
03 4 4 Line 2: Power failure.
.. .. .. ..
31 32 32 Oven door open.