AK-PC
551
User
Guide RS8GY302 © Danfoss 2015-06
13
Sc3 offset
Temperature offset for regulation with fluid reference.
Regulation reference = Sc3 measu Sc3 offset
Min: 0 K
Max: 20 K
Fac: 6 K
Min. reference
Set the lowest permissible regulation reference here
Min: -25°C (-1.0 bar)
Max: 100°C (159 bar)
Fac: 10°C (5.0 bar)
Max. reference
Set the highest permissible regulation reference here
Min: -25°C (-1.0 bar)
Max: 100°C (159 bar)
Fac: 50°C (35.0 bar)
Heat recocery SP
Temperature set point for heat recovery function (only when the function is selected during
configuration)
Min: 20°C (-1.0 bar)
Max: 90°C (159 bar)
Fac: 50°C (30.0 bar)
Heat rec. ramp down
Ramp-down of regulation reference after heat recovery
Set how quickly the reference for condenser pressure should be made after heat recovery
ends. Enter the change in degrees Kelvin per minute.
Min: 0,1 K
Max: 100 K
Fac: 1 K
Capacity limit night
Capacity limitation at night
The speed of the fans can be limited here when regulating using speed control.
During step-by-step activation, the start of the step-by-step process is limited.
Min: 0 %
Max: 100%
Fac: 100%
Gain factor Kp
Amplification factor for PI regulation
If the Kp value is lowered, regulation runs more smoothly
Min: 1
Max: 30
Fac: 10
Integration time Tn
Integration time for PI regulation
If the Tn value is increased, regulation will run more smoothly
Min: 30 s
Max: 240 s
Fac: 180 s
Fan configuration
Configuration of fans
Control sensor
Selection of regulation sensor:
• Pc pressure transmitter
• S7 media temperature sensor (Pc must be installed for safety monitoring)
AI-demand
Pc / S7
Fac: Pc
Reference mode
Set the reference for regulation here
• Fixed reference; the reference here will be the defined set point
• Variable reference; the reference here will follow the outside temperature, which is meas-
ured with Sc3.
AI-demand
Setpoint / Floating
Fac: Setpoint
Capacity ctrl. mode
Set the way in which the fans should be controlled here
• Variable; the fans are controlled by a 0-10 V signal from an analogue output. If it is defined in
“VSD Start via DO”, a relay will be able to start and stop the frequency converter.
• Step; on/off control of fans will be via relays
• Va step. The signals are parallel, so external wiring can switch over to step, e.g. if the
frequency converter fails.
AO-demand
Step / Speed
Fac: Step
No. of fans
Enter the number of fans here.
For step-by-step activation, select the number of relays. The relays will cut in/out sequentially,
e.g. 123-321.
For speed control, select 1 or higher. No relay is reserved, but the setting makes it possible to
define the monitoring of fans.
DO-demand
Min: 0
Max: 8
Fac: 0
Control type
Normally, PI-regulation is used, but this can be changed to a P-regulation if the design of the
system necessitates this.
• PI Ctrl: Regulation is carried out here with as little deviation between the reference and
measurement as possible.
• P-band ctrl: Capacity is cut in here after proportional regulation.
P / PI
Fac: PI
VSD Start speed
Set the start value of the frequency converter here.
The value must be higher than the VSD min. speed value.
Min: 0%
Max: 40%
Fac: 20%
VSD Min speed
Set the minimum speed of the frequency converter here.
If lower capacity is required, this minimum speed should be maintained all the way down to
0% capacity. At 0% capacity, the system stops completely.
Min: 0%
Max: 40%
Fac: 10%
VSD Start via DO
Define whether a relay should be connected to the frequency converter start/stop function
here:
• No: no relay
• Yes: the relay pulls in when the frequency converter needs to be in operation.
DO-demand
Yes / No
Fac: No
Monitor fan safety
Define whether safety monitoring of the condenser fans should be performed.
• None: no monitoring
• Individual: a DI input is reserved for each fan
• Common: a DI input that is common for all condenser fans is reserved .
DI-demand
Common /Indi-
vidual
Fac: None
Fan at comp. OFF
Select the way in which the fans should be controlled when all the compressors have
stopped.
• Normal regulation: Fans to be controlled in compliance with normal regulation.
• Energy-optimised: Fan capacity will be maintained at between 0 and 49% in a p-band of
5-15 K above reference.
Normal/Optimized
Fac.: Normal
Heat recovery via DI
Define whether a heat recovery cycle should be started with a signal on a DI input here.
• No: No function
• Yes: A DI input is reserved. When a signal is registered, the heat recovery function reference
will become active.
DI-demand
Yes / No
Fac: No