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Siemens Building Technologies Commissioning Guide CM1G5192en
HVAC Products 7 Application examples 26.02.2003
7.8 Application example 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
Hand
Auto
SED2
0
I
P
Fn
P(1)
Hz
L1
L2
L3
PE
L1 L2 L3
20
9
5
3
2
SED2
uvw
M
3
21
22
23
24
25
6
M
UG
Fuses
Building Management System
(BMS)
Inspection switch
5192A08en
Error
Com
Run
Com
Relay 1
Relay 2 status to compressor
start circuit
LLSV relay interlock
QBE620-P25
HP sensor
28
Pump
Notes: When the chiller interlock latches, the VSD will start and maintain the temperature 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.
7.8.1 Parameter changes
Start with quick commissioning according to application example 1
Par. no. Value Parameter function Function selection
P0501(0) 4 Type of sensor Set input scale to range of QBE620 – P25
P0700(0) 2 Selection of command source Set commands from terminals
P0701(0) 16 Function of digital input 1 in “Auto” mode Set DI-1 for fixed freq SP + ON
P1210 3 Restart after fault / mains break Auto restart after mains fail
P1000(0) 3 Selection of frequency setpoint Setpoint by fixed frequency
P0756(0) 0 Analog input Unipolar voltage input (DC 0…10 V)
P1080 5 Motor minimum frequency Minimum frequency
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
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