Hvac Functions Of The Sed2; Pid Controller - Siemens SED2 series Operating Instructions Manual

Parameterizing the PID
controller
(commissioning)
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HVAC Products
6.4

HVAC functions of the SED2

The functions listed below were implemented specifically in the SED2 for HVAC
applications.
6.4.1

PID controller

In order to achieve independent control within a stand-alone application by means of
the SED2 VSD, Siemens SBT implemented a proven PID controller. This controller
allows for temperature (LG-Ni 1000), pressure, and speed control.
The factory settings for the implemented PID parameters are designed for pressure
control.
For temperature or speed control, the controller's time constants must be adjusted to
the new control loop. See "Parameterizing the PID controller" below.
P2253 : setpoint source
P2261 : setpoint filter timeconstant
r 2262 : filtered setpoint
P2264 : feedback source
P2267 : feedback threshold max
P2268 : feedback threshold min
P2270 : function sequence
P2271 : transducer type
r 2272 : scaled feedback
P2274 : derivative time
Fixed setpoint
The setpoint and the actual value signal are to be displayed as a percentage (%) or
absolute value. Make sure, however, that the two signals match each other.
P2201
Enter fixed setpoint
(or absolute value in %).
The setpoint is active if switching
command "ON" is sent to DIN1.
P2253
Set to value 2224 (fixed PI setpoint).
P0701[0]
Enter value 16
(sets DIN1 to ON with fixed setpoint; see
section 6.3.1 Digital inputs ).
Define the type of analog input 2 for the actual value signal
(see section 6.3.2 Analog inputs).
SED2 variable speed drives
Programming
: transient error signal
r 2273
: P gain
P2280
: I gain
P2285
P2293 : ramp-up/-down time of PID limit
P2291 : PID output upper limit
P2292 : PID output lower limit
P2304 : actuator opening time
P2305 : actuator closing time
P0731/P0732 : 53.A = PID output at lower limit
P0731/P0732 : 53.B = PID output at upper limit
PID
CONTROLLER
External setpoint
Note:
Analog input
See the section on analog inputs for the
parameter settings.
P2253[0]
Set to 755
(setpoint is configured to AIN 1).
P0756[0]
Select the type of analog input 1 for the
setpoint. See section Analog inputs.
P0757[0] to P0760[0]
Set scaling of AIN 1.
P0756[1]
r2294: PID output
5192Z21en
CM1U5192en
01.2002