Digital Alarm Block

Purpose

The Digital Alarm (DA) block sends and receives digital data (1 or 0)
from an I/O driver or OPC server to provide alarm control. Using this
block, you can suspend alarms and define an alarm condition and an alarm
priority. The block can also wait a specified time interval before issuing
an alarm, close a contact when an alarm occurs, and automatically reissue
and acknowledge alarms.

Features

The Digital Alarm block:

• Is a primary block.
• Can be used as a
  stand-alone block.
• Generates alarms
  when values are outside of defined limits.
• Sends and receives
  values from an I/O driver or OPC server when placed in Automatic mode.
• Receives values from
  operator input in the iFIX WorkSpace, from scripts, from Program
  blocks, or from Easy Database Access programs when operating in Manual
  mode.
• Can be used in a
  chain with exception-based or time-based processing.
• Can be configured
  using Continuous Output that allows blocks to attempt to write the contacts
  with every scan, even if the value being written in unchanged. Without
  Continuous Output, the block only attempts to write to the defined contact
  tag when a value has changed and it needs to be written to the PLC. (In
  this case, the write is a one-time attempt, so if it fails, the write
  will not be retried until the block needs to write a new value.)

NOTE:
Because the contact mode of “Never” does not reset the contact, the Continuous
Output option is not supported for this contact mode.

• Can be configured
  using the Suppress COMM Alarm option, which allows you to separate the
  original alarm condition from the COMM alarm, and return the DA block
  to the same state as it was prior to a COMM alarm. If you disable the
  Suppress COMM Alarm option, DA blocks handle one alarm at a time. (As
  a result, it is possible that acknowledgement of a COMM alarm could cause
  the ACK bit in the PLC to be written, and the original alarm condition,
  if already acknowledged, could re-alarm.)
• Can be configured to enable the Event messaging (Suspend mode), which applies suppression behavior to disable alarm processing but shows an alarm message. When the tag is in suspend mode, the Alarm state is set to OK. Since the Alarm is an alarm message only, it does not appear in the alarm summary. Alarm processing continues with each alarm state transition recorded in the alarm loggers; however, this does not display in the alarm summary. The alarm state contact (tag) is not processed.

See Also

Alarm States, Contacts,
and the Digital Alarm Block

Typical Uses

Digital
Alarm Block – Typical Uses

Example

Digital
Alarm Block Example

Fields

Digital
Alarm Block Fields

Important Notice

You do not have the latest version of iFIX! You are missing out on the newest capabilities and enhanced security.

For information on all the latest features, see the iFIX product page.

For more information on upgrades, contact your GE Digital sales agent or e-mail [email protected].

For the most up-to-date documentation, go here.