Technical data

Appendix A: Parameter Reference List
Siemens Building Technologies, Inc. 125
P2270 PID feedback function selector
Min: 0 Def: 0 Max: 3
Level 3
Details:
Applies mathematical functions to the PID feedback signal, allowing multiplication of the result by P2269 (gain applied to
PID feedback).
Enum:
0=Disabled 1=Square root (root(x)) 2=Square (x*x) 3=Cube (x*x*x)
P2271 PID transducer type
Min: 0 Def: 0 Max: 1
Level 2
Value:
0 : [default] If the feedback signal is less than the PID setpoint, the PID controller will increase motor speed to correct this.
1 : If the feedback signal is greater than the PID setpoint, the PID controller will reduce motor speed to correct this.
Enum:
0=Disabled 1=Inversion of PID feedback signal
Note:
It is essential that you select the correct transducer type.
If you are unsure whether 0 or 1 is applicable, you can determine the correct type as follows:
1. Disable the PID function (P2200=0).
2. Increase the motor frequency while measuring the feedback signal.
3. If the feedback signal increases with an increase in motor frequency, the PID transducer type should be 0.
4. If the feedback signal decreases with an increase in motor frequency the PID transducer type should be set to 1.
r2272 CO: PID scaled feedback
Min: - Def: - Max: -
Level 2
Note:
r2272=100% corresponds to 4000 hex.
r2273 CO: PID error
Min: - Def: - Max: -
Level 2
Note:
r2273=100% corresponds to 4000 hex.
P2274 PID derivative time
Min: 0 Def: 0 Max: 65535
Level 2
Note:
Set PID derivative time
P2279 PID neutral zone
Min: 0.00 Def: 0.00 Max: 100.00
Level 3
Note:
Set PID derivative time
P2280 PID proportional gain
Min: 0.000 Def: 3.000 Max: 65.000
Level 2
Details:
Allows you to set proportional gain for standard PID controller. For best results, enable both P and I terms.
Dependency:
If P term=0, I term acts on the square of the error signal.
Note:
If the system is prone to sudden step changes in the feedback signal, P term should normally be set to a small value (0.5)
with a faster I term for optimum performance.
The D term (P2274) multiplies the difference between the present and previous feedback signal thus accelerating the
controller reaction to an error that appears suddenly.
The D term should be used carefully, since it can cause the controller output to fluctuate as every change in the feedback
signal is amplified by the controller derivative action.
P2285 PID integral time
Min: 0.000 Def: 0.000 Max: 60.000
Level 2
Note:
See P2280 (PID proportional gain).
P2291 PID output upper limit
Min: -200.00 Def: 100.00 Max: 200.00
Level 2
Dependency:
If F max (P1082) is greater than P2000 (reference frequency), either P2000 or P2291 (PID output upper limit) must be
changed to achieve F max.
Note:
P2291=100% corresponds to 4000 hex (as defined by P2000 [reference frequency] ).
P2292 PID output lower limit
Min: -200.00 Def: 0.00 Max: 200.00
Level 2
Dependency:
A negative value allows bipolar operation of PID controller.
Note:
P2292=100% corresponds to 4000 hex.
P2293 Ramp up/-down time of PID limit
Min: 0.00 Def: 0.00 Max: 100.00
Level 3
Detail:
Sets maximum ramp rate on output of PID. When PI is enabled, the output limits are ramped up from 0 to the limits set in
P2291 (PID output upper limit ) and P2292 (PID output lower limit). Limits prevent large setup changes appearing on the
output of the PID when the VFD is started. Once the limits have been reached, the PID controller output is instantaneous.
These ramp times are used whenever a Run command is issued.
Note:
If an OFF1 or OFF3 are issued, the VFD output frequency ramps down as set in P1121 (ramp-down time) or P1135
(ramp=down time).