PRESSURE CONTROLLER operating manual
9
Applications
Valve Orientation
Your pressure controller will control process pressure to whatever side
the pressure sensor is exposed to.
Pressure Control Application,
Upstream Valve (downstream pressure control)
With the valve located on the upstream side, the sensor will be exposed
downstream, therefore it will control pressure downstream. This config-
uration follows our standard pressure control algorithm (valve opens to
increase pressure, closes to decrease pressure). For example:
Gas Supply Pressure Regulator
Pressure Controller
Process Flow Exit Port
Up-Stream Valve
Back Pressure Control Application,
Downstream Valve (upstream pressure control)
A pressure controller with a downstream valve configuration will result in
the sensor exposed to the upstream pressure. Due to this, the controller
will be regulating the upstream pressure, and this configuration is known as
a back pressure controller. This configuration follows our inverse pressure
control algorithm (valve closes to increase pressure, opens to decrease
pressure). For example:
Note:
Back pressure controlers include “DS,” for downstream valve, in their part codes.
Changing the Valve Orientation
The valve position on your Alicat pressure controller can be switched in the
field. In addition to the valve switch, the controller must be configured for
either forward pressure control (default control) or back pressure control
(inverse control). If you need to switch from forward to back control, a video
and explanation can be found at
alicat.com/valve-direction-change
.
Gas Supply
Pressure Regulator
Pressure Controller
Process
Flow Exit Port
Down-Stream Valve
