Trane Tracer MP501 Installation, Operation And Maintenance Manual page 33

Table 7. Starting gain values for applications
Loop
Duct static pressure
Discharge air cooling
An alternative way to calculate the proportional and integral gains is by using the following
calculations:
The proportional gain is scaled by a factor of 0.80, so it contributes 80% of the final output. The
integral gain contributes 20% of the final output.
Example
In a duct static pressure system, an actuator can move the inlet guide vanes of an air handler from
0–100%, so the output range is 100— a throttling range of 2.0 in. of water column (wc) is desirable.
A change in pressure of 2.0 in. wc. or more will drive the output from 0–100% or vice versa. The
calculations look like this:
Therefore, based on the desired throttling range of 2.0 in. wc., the starting proportional gain is 40
and the starting integral gain is 10.
CNT-SVX08F-EN
Output
Inlet guide vane or variable frequency
drive (VFD) position 
0–100%
Electric/pneumatic 
5.0–15.0 psi (34–103 kPa)
0.80 output range

Proportional gain = ---------------------------------------------------- -
throttling range
0.20 output range

Integral gain = ----------------------------------------------- -
throttling range
0.80
Proportional gain
=
---------------------------------------------------------- -
throttling range
0.20 output range

Integral gain
=
---------------------------------------------------------- -
throttling range
Throttling
Range
2.0 in. wc. 
(0.5 kPa)
20.0°F (11.1°C)
output range 0.80 100
 
=
------------------------------ -
2.0 in. wc.
0.20 100

=
------------------------------ -
2.0 in. wc.
Proportional Integral
Gain Gain
40.0 (160) 10.0 (40.0)
0.4 (4.0) 0.1 (1.0)
40
=
10
=
PID Control
33