C
hapter
Ⅵ
A
pplications
6.4 Ventilation system
Control requirements:
The ventilation system shall be able to send fresh air into the room as well as ex-
haust the waste gas out of the room.
1. Waste gas exhaust unit and fresh air forced-draft unit must be installed in the
room.
2. The ventilation system shall be controlled by the control monitor such as smoke
sensor, temperature sensor etc.
3. No over atmospheric pressure is allowed in the room at any time.
4. The fresh air forced-draft unit cannot be put into service until the ow monitor
indicates that the waste gas exhaust unit is in normal operation.
5. In case of any fault in the ventilation system, the alarm lamp shall be on.
The ventilation system is controlled by the ow sensor. If there is no atmosphere
ow in the room, then after a short time the sensor will cut off this system and
send the failure report.
The Function Block Program Diagram is as follows:
Description:
I1: connected to the start button
I2: connected to the stop button
I3: connected to the waste gas ow monitor
I4: connected to the fresh air ow monitor
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Q1: connected to the waste gas exhaust equipment
Q2: connected to the fresh air forced-draft equipment
Q3: connected to the alarm lamp