Trane Direct-Fired Indoor and Outdoor Make-Up Air Units, MUA-SVP01A-EN manual Reverse acting

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

.05” 0%

override

scaler

.03” 100%

.03” PID 0-100%

.03” 0%

override

scaler

Input > .03”?

>	0-100%
=	Output
<

Input < .03”?

Min User SP .00” 100%

MUA-SVP01A-EN • Direct-Fired Indoor and Outdoor Units 23