ALM_ALARM

Type Function block

Description The function block is used to send alarm states to the OPC UA server. The ALM_STATE structure connected to ALARM holds the alarm state. With each change of the ACTIVE input, the new state is sent to the OPC UA server. The function block has to be executed until the DONE output is set to TRUE. The DONE output is set to FALSE if, for example, many alarm states are sent simultaneously.
The AUTO_ACK and AUTO_CONF inputs can be used to determine whether the alarms require an acknowledgment (AUTO_ACK) or confirmation (AUTO_CONF). If both inputs are TRUE, the alarm is removed as soon as the ACTIVE input switches to FALSE. If an alarm acknowledgment or confirmation is required, the function block has to process the alarms, i.e., it has to be further executed.

Notes Function blocks have to be instantiated. The instance name of the function block has to be declared in the 'Variables' table of the POU where the FB is going to be used. The instance name must be unique within the POU.

Parameters Inputs
ACTIVE

Data type: BOOL

Description: Indicates whether the alarm condition is active.
TRUE: Alarm condition is active.
FALSE: Alarm condition is inactive.

MESSAGE

Data type: STRING

Description: Alarm message to be shown to the user.

AUTO_ACK

Data type: BOOL

Description: TRUE: No alarm acknowledgment required.
FALSE: Alarm requires acknowledgment.

AUTO_CONF

Data type: BOOL

Description: TRUE: No alarm confirmation required.
FALSE: Alarm requires confirmation.

RESET

Data type: BOOL

Description: With a rising edge at the RESET input an alarm can be acknowledged and confirmed by the alarm source (instead of the client). A new message with ACKED_STATE=FALSE and ACKED_CONFIRMED=FALSE (elements of the ALM_STATE structure; see below) is sent to inform the OPC UA server.

Input/Output
ALARM

Data type: ALM_STATE
(see below for a description of the ALM_STATE structure elements)

Description: Alarm state

Outputs
DONE

Data type: BOOL

Description: Indicates whether the function block has completed sending the message (TRUE = completed, FALSE = continue calling the FB until DONE = TRUE).

RETAIN_STATE

Data type: BOOL

Description: Indicates whether the alarm has been displayed to the user.

ALM_STATE structure ALM_STATE structure elements

Structure element Data type Description

ACTIVE_CHANGED LDATE_AND_TIME Optional timestamp for the last change of ACTIVE_STATE.

ACKED_CHANGED LDATE_AND_TIME Optional timestamp for the last change of ACKED_STATE.

CONFIRM_CHANGED LDATE_AND_TIME Optional timestamp for the last change of CONFIRMED_STATE.

SUPPRESSED_CHANGED LDATE_AND_TIME Optional timestamp for the last change of SUPPRESSED_STATE.

RETAIN_CHANGED LDATE_AND_TIME Optional timestamp for the last change of RETAIN_STATE.

ALARM_CHANGED LDATE_AND_TIME Optional timestamp for the last change of ALARM_CHANGED.

ALARM_ID STRING Unique ID (name) of the alarm within the controller.

ALARM_TYPE STRING Type of the alarm.

MESSAGE STRING Message to be shown to the user.

LANG STRING Reserved. Should be empty string.

COMMENT STRING Reserved. Should be empty string.

USER STRING Reserved. Should be empty string.

SEVERITY INT Severity of the alarm (1 = information; 1000 = fatal error).

ACTIVE_STATE BOOL Indication if the alarm condition is true.

ACKED_STATE BOOL Acknowledged state of the alarm (the user has seen the alarm).

CONFIRMED_STATE BOOL Confirmed state of the alarm (the user has resolved the problem causing the alarm).

SUPPRESSED_STATE BOOL The OPC UA server wants to hide the alarm.

RETAIN_STATE BOOL TRUE to indicate that the alarm should be displayed to the user.

reserved0 USINT Reserved

reserved1 INT Reserved