Lennox Prodigy M2 Application Manual page 41

B Start system. Analog output value will be at the ManRS value (%).
C Monitor system. System should be stable. If system is not stable at this point check for other problems. Adjusting the PID
parameters will not solve this problem.
D If system is stable, gradually increase the P" parameter until system starts oscillating (moving above and below
setpoint, continuously).
E Reduce the P" parameter to 40−70% of the value set in step 6.
F Gradually start adding some I" by setting the I" ECTO parameter to 127 and reduce setting until the steady state
error (offset) is reduced to an acceptable level.
G If necessary, increase the D" parameter to reduce overshoot. Use of D" can increase settling time and/or lead to
instability.
H NOTE − In most cases, it's best to not use any D" parameter.
No. Name
0.09 VAV_PID_ManRS
0.10 PID_P_Constant
0.11 PID_I_Constant
0.12 PID_D_Constant
8.22 Exh_Fan_ManRS
Stg_1_Off_Delay
Exh_Fan_PID_P_
8.23
Constant
Stg_2_SP
Exh_Fan_PID_I_
8.24
Constant
Stg_2_DB
Exh_Fan_PID_D_
8.25
Constant
Stg_2_On_Delay
9.08 AO1_PID_ManRS
9.09 AO1_PID_P_Constant
9.10 AO1_PID_I_Constant
9.11 AO1_PID_D_Constant
General Purpose PID Control Constants for GP Analog Output 2 (TB22−12)
9.19 AO2_PID_ ManRS
9.20 AO2_PID_P_Constant
9.21 AO2_PID_I_Constant
9.22 AO2_PID_D_Constant
Table 30. Summary of PID Constants ECTO Parameters
Variable Air Delivery PID Constants
Min Default Max
Units
0 60 100 Counts
0 60 100 P:%
0 17 127 Counts
0 12 127 Counts
0 0 127 Counts
VAV Exhaust Fan PID Control Constants
0 50 100 Counts
0 50 100 P: %
0 100 200 A:Sec.
0 20 255 Counts
0 .78 10.0 R:Volts
0 20 100 P:%
−0.5 −.42 0.5 M:"w.c.
0 64 255 Counts
0 64 100 P:%
0 0.25 1.0 L:"w.c.
0 0 127 Counts
0 0 254 A: Sec.
0 50 100 Counts
0 50 100 P:%
0 0 127 Counts
0 0 127 Counts
0 0 127 Counts
0 50 100 Counts
0 50 100 P:%
0 0 127 Counts
0 0 127 Counts
0 0 127 Counts
Description
VAV supply PID manual reset value. If minimum output, ECTO 0.06 or
0.07 is greater, a computed ManRS value is used. See ECTO 0.06 and
0.07.
VAV or CAVB supply PID Proportional constant.
VAV or CAVB supply PID Integral constant.
VAV or CAVB supply PID derivative constant.
Exhaust fan PID loop manual reset value.
Stage 1 off−delay. (Only used for 2 stage operation)
Exhaust fan PID loop proportional constant. The P constant must be
limited to 127. Recommended setting = 17.
Staged 2 setpoint.
Exhaust fan PID loop integral constant. The I constant must be limited
to 127. Recommended setting = 12.
Staged 2 deadband.
Exhaust fan PID loop derivative constant.
Staged 2 on−delay.
Analog output channel 1 PID loop manual reset value.
Analog output channel 1 PID loop proportional constant.
Analog output channel 1 PID loop integral constant.
Analog output channel 1 PID loop derivative constant.
Analog output channel 2 PID loop manual reset value.
Analog output channel 2 PID loop proportional constant.
Analog output channel 2 PID loop integral constant.
Analog output channel 2 PID loop derivative constant.
Page 41
9. Supply Air Delivery
PRODIGYT M2 UNIT CONTROLLER