Micromod MOD: 30ML Functions Data Base Reference User Manual

Page 59

MOD 30ML Functions

PROCESS ALARM DISPLAY BLOCK

Alarm Clear

Time (Group Scan Cycles)

750

500

250

0.000000

1000

TRUE

FALSE

Alarm

Active

HIGH ALARM CALCULATION

Process Input

Floating Point

Value

Hysteresis Value (50)

Configured Trip Condition is >=

Alarm Value >= Trip Value

Alarm Value < Trip Value - Hysteresis

Figure 2-20. Example of Process Alarm Tripping (Floating Point Data)

An alarm can be acknowledged in 1 of 6 ways:

• By using the Alarm Acknowledge discrete input. This acknowledgment is edge triggered

so that a value of 0 (FALSE) followed by a value of 1 (TRUE) acknowledges the alarm.
The quality of this input is ignored if bad inputs are accepted.

• By using the Process Alarm Acknowledge discrete input to the System Event block. This

acknowledges all process alarms.

• By using the Global Acknowledge discrete input to the System Event block. This

acknowledges all diagnostic alarms, process alarms, and notification/request messages.
The System Event block handles global acknowledgment if the block or its loop is in
HOLD or OFF. Global acknowledgment will not occur if the block or its loop is in DEBUG.

• By setting the Suppress Alarm Calculation to YES.
• By receiving an alarm acknowledge message into this block’s message handler from

some other device which causes a FALSE value to be written to the Unacknowledged
field of this block.

• By writing the value FALSE to the Unacknowledged field of this block.

2-51