LX Series Unit Ventilator Controller User's Guide
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The Unit Ventilator Controller provides PID control settings through its
configuration wizard. Figure 21 shows the PID screen.
For space temperature, discharge temperature, CO
2
, and humidity levels, there are
settings for proportional, integral, and derivative gains. Each of these gains
contributes to the final output as shown in Figure 22. They are discussed separately
in the following sections.
Proportional
Proportional control provides an output that is proportional to the error. The error
is multiplied by a number called the gain. The result is used to produce the output.
For example, if the room temperature is 69°F and the setpoint is 72°F, then the
error is 3F°. If the gain is equal to 10% per °F, then the output is 30% of the
maximum output value.
Integral
The integral component has a gain and time setting. These work together to
remove errors that accumulate over time.
Figure 21: PID Screen of the Unit Ventilation
Controller Configuration Wizard
Proportional
Integral
D erivative
Total O utput
+
+
=
Figure 22: Total Output Composed of P, I, and D Components
