Siemens 125-5033 소유자 매뉴얼 - 페이지 22

{카테고리_이름} Siemens 125-5033에 대한 소유자 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. Siemens 125-5033 35 페이지. Two-state constant volume fume hood controller

Fume Hood Controller Owner's Manual

Alarm Strategies

One approach is to use the ALARMs to indicate a condition that requires immediate attention

and the WARNINGs to indicate a condition that may require attention but is not urgent. In that

case, the alarm limits would be set to indicate that it is unsafe to work at the fume hood. The

warning limits would be set at a level that is safe, but indicates that the system may not be

operating correctly. These values should be selected by the person responsible for laboratory

safety.

The delay timer is adjustable and should be selected with safety in mind. Laboratory safety

procedures will not be effective if there are numerous nuisance alarms. The delay timer

should be set at a sufficiently large interval to prevent nuisance alarms. However, if the delay

timer interval is excessively large, there is a risk of having a laboratory worker standing in

front of an ineffective fume hood for a prolonged period. The delay timer interval should be

selected by the laboratory safety officer with the above considerations in mind.

Under certain emergency conditions, such as a spill in the fume hood, it may be necessary to

purge the air from the fume hood. The Emergency Purge sequence enables the fume hood

user to override normal airflow setpoint and temporarily increase the airflow beyond the value

needed to maintain the airflow setpoint.

The Emergency Purge overrides any other control mode in the Fume Hood Controller and

has two modes of operation; maximum purge, and controlled purge.

The maximum purge moves the exhaust airflow control device to full open and holds it there

regardless of airflow. This mode has the advantage of providing immediate expulsion of the

contaminating agent, but may cause airflow problems in the fume hood and reduce the

airflow capacity at other fume hoods.

The controlled purge continues to modulate the exhaust airflow control device and controls

the airflow, but at a higher than normal level.

The Fume Hood Controller can be set up to purge in either mode or to start in maximum

purge and then switch to a controlled purge after an adjustable amount of time.

The Emergency Purge sequence is initiated by pressing the Emergency Purge button on the

ODP. When the Emergency Purge button is pressed, the fume hood will go to the maximum

purge for the time selected in the emergency timer. After the emergency timer elapses, the

Fume Hood Controller will begin actively controlling the airflow, but at an increased setpoint.

The Emergency Purge sequence is canceled by pressing the Emergency Purge button a

second time. The ODP indicates an Emergency Purge sequence in three ways:

•

The red LED illuminates.

•

The horn sounds.

•

EMERGENCY PURGE and EEE display.

Siemens Building Technologies, Inc.