Trane DFIA Programming Manual page 23

MUA-SVP01A-EN • Direct-Fired Indoor and Outdoor Units
Functions
pressure to be+0.03" but does not want it to drop below 0.0" or go above +0.05".
The parameters entered on the keypad display will be:
PID Select Reverse (as input increases output decreases)
High Input Val .10
Low Input Val -0.10
User Ctrl SP 0.03
Max User SP 0.05
Min User SP 0.00
The pressure transducer compares the pressure outside the space to the
pressure inside the space and transmits a corresponding signal to the AdaptAire
controller. The controller compares this signal to the desired user control
setpoint (0.03") and uses the PID loop to modulate the output from 0-100% (0-
10Vdc). The output is connected to the VFD that changes speed to maintain the
specified building pressure.
If the building pressure is 0.03", the output from the controller will be determined
by the PID control sequence, and the override will have no effect on the output.
If the building pressure is more than 0.03", the output from the controller will be
determined by the PID control sequence or the override whichever is less.
If the building pressure is less than 0.03", the output from the controller will be
determined by the PID control sequence or the override whichever is more.
Figure 3. Reverse acting
Max User SP
User Ctrl SP
Min User SP
.05" 0%
Input > .03"?
override
scaler
.03" 100%
.03" PID 0-100%
.03" 0%
override
scaler
Input < .03"?
.00" 100%
>
0-100%
=
Output
<
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