Acknowledge bit, Handshake bit, Acknowledge bit – 13 handshake bit – 13 – Rockwell Automation FactoryTalk View Site Edition Users Guide User Manual
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For example, the following expression checks whether any of a group of tags is in alarm:
ALM_IN_ALARM (alarm*)
where alarm* represents all tags whose names begin with alarm.
If one or more of these tags are in alarm, the expression result is 1. If all of the tags are out
of alarm, the expression result is 0.
Acknowledge bit
An acknowledge bit is a digital tag that can be used to:
acknowledge an HMI tag alarm.
monitor the acknowledged state of an HMI tag alarm.
When you set up an acknowledge bit for a tag, the HMI server monitors the value of the
acknowledge bit and acknowledges the alarm automatically, when the value of the
acknowledge bit changes from 0 to 1.
In the alarm log file, this transaction is identified by RmAck (Remote Acknowledge) in
the TransType (transaction type) field.
When an operator acknowledges an alarm, the acknowledge bit is set to 1. If the Auto
Reset feature is enabled, the HMI server resets the acknowledge bit to 0 when the tag
goes back into alarm.
The acknowledge bit must be set up as a digital tag in the HMI tag database. For details
about setting up an acknowledge bit, see the FactoryTalk View Site Edition Help.
Handshake bit
A handshake bit is a digital tag that can be used to monitor the status of an HMI tag alarm.
When you set up a handshake bit for a tag, the HMI server sets the handshake bit to 1
when the tag goes into alarm. If the Auto Reset feature is enabled, the HMI server sets the
handshake bit to 0 when the tag goes out of alarm.
The handshake bit must be set up as a digital tag in the HMI tag database. For details
about setting up a handshake bit, see the FactoryTalk View Site Edition Help.
If the wildcard pattern in an alarm expression matches a large number of tags, it could take more
time to resolve the expression.
The HMI server monitors the value of each acknowledge bit tag. Using many acknowledge bits
can slow down the system considerably.