How to create a pressure controlled zone.

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I am aiming to design a zone with positive pressure using AirflowNetwork without distribution through the function AirflowNetwork:ZoneControl:PressureController. The engineering reference says that it can be acheived by having zone exhaust fan flow rate in a controlled zone through defining an OA mixer and an exhaust fan in a controlled zone to reach the pressure setpoint by adjusting an exhaust fan flow rate. My querie is: How the OA mixer can be created and in which specific field in EP regarding my case. And in order to control the pressure, then there should be supply and exhaust fans, in this case, will the OA mixer take the supply fan task and work as a supply fan or I have to define a seperate supply fan?

Thank you in advance.