Application 7; Application 8 - Siemens SED2 Commissioning Manual

Par. no. Value Parameter function
P2253(0) 2224 PID setpoint
P2264(0) 755.0 PID feedback
P2274 0 s PID derivative action time
P2280 5 PID proportional gain
P2285 20 s PID integral action time
P2306 0 PID acting direction
P2390 35% Hibernation frequency
P2391 90 s Hibernation timer
P2392 -2% Restart PID controller deviation
r2262 Filtered PID setpoint
r2272 PID scaled feedback
r2273 PID error
r2294 PID output

7.8 Application 8

Condenser tower shall be controlled with the help of the integrated PID controller.
ON / OFF by LLSV relay interlock
–
QBE620 for pressure control
–
Indication of operation via relay output 2
–
L1
L2
L3
PE
Fuses
L1 L2 L3
20
21
22
23
24
25
SED2
P(1)
Hz
5
I Hand Fn
0 Auto P
9
3
SED2 2
28
u v w
Inspection switch
M
3
Notes: When the chiller interlock latches, the VSD will start and maintain the pressure setpoint (P2201). If the
output of the VSD drops below the hibernation setpoint P2390, and the hibernation timer has elapsed
(P2391), the VSD will drop from the minimum motor frequency (P1080) to zero, and turn off. When the HP
exceeds the setpoint by 5% (P2392), the VSD will restart and ramp up to maintain the setpoint once more.
This feature allows the minimum motor frequency to be set to protect the motor from overheating and
stalling, while allowing the motor to turn off when not needed to prevent overcooling during the winter
months.
52 / 100
Siemens
Building Technologies
Error
Relay 1
Com
Run
Relay 2
Com
M U G
QBE620-P25
HP Sensor
Pump
Commissioning Guide
7 Applications
Function selection
PID setpoint source
Sets PID feedback source to AIN 1
Derivative action time
Proportional band
Integral action time
Direct acting loop
Hibernation setpoint [%]
Hibernation timer in seconds
Restart – PID error
Display actual setpoint in C
Display actual condenser temperature
Display actual PID error in %
Display actual VSD output in %
LLSV relay interlock
5192A08en
DIP switch setting
ON 1 = Analog input 1
■ ■
OFF OFF = DC 0...10 V
1 2 ON = 0...20 mA
2 = Analog input 2
OFF = DC 0...10 V
ON = 0...20 mA
CM1G5192en
29.07.2010