4 in-process operation, 4-1 mode transition, 4-2 generation of alarm – Yokogawa DO202 2-Wire Dissolved Oxygen Analyzer User Manual

Page 27: 4-2-1 indication of alarm, 4-2-2 alarms and events, 4 in-process operation -22, 4-1 mode transition -22, 4-2 generation of alarm -22, 4-2-1 indication of alarm -22, 4-2-2 alarms and events -22

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IM 12A00A01-61E

3-22 Foundation Fieldbus

3-4 In-process operation
This chapter describes the procedure performed when changing the operation of the function block of the
EXA in process.

3-4-1 Mode Transition
When the function block mode is changed to Out_Of_Service, the function block pauses and a block alarm
is issued.

When the function block mode is changed to Manual, the function block suspends updating of output val-
ues. In this case alone, it is possible to write a value to the OUT parameter of the block for output. Note that
no parameter status can be changed.

3-4-2 Generation of Alarm

3-4-2-1 Indication of Alarm

Figure 3.12 Error Identification on Indicator

3-4-2-2 Alarms and Events

Following alarm or event can be reported by EXA as an alert if allowed.

Analog Alerts
(Generated when a process value exceeds threshold)

By AI1 Block

Hi-Hi Alarm, Hi Alarm, Low Alarm, Low-Low Alarm

By AI2 Block

Hi-Hi Alarm, Hi Alarm, Low Alarm, Low-Low Alarm

By AI3 Block

Hi-Hi Alarm, Hi Alarm, Low Alarm, Low-Low Alarm

Discrets Alerts
(Generated when an abnormal condition is detected)

By Resource Block

Block Alarm, Write Alarm

By Transducer Block

Block Alarm

By AI1 Block

Block Alarm

By AI2 Block

Block Alarm

By AI3 Block

Block Alarm

Update Alerts
(Generated when a important (restorable) parameter is updated)

By Resource Block

Update Event

By Transducer Block

Update Event

By AI1 Block

Update Event

By AI2 Block

Update Event

By AI3 Block

Update Event

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