Danfoss Metasys N2 Programming Guide

the system (boost to be set in parameter 22-45 Setpoint
Boost).
The feedback from the pressure transducer is monitored,
and when this pressure has dropped with a set percentage
below the normal setpoint for pressure (P
set
), the motor
ramps up again and pressure controlled for reaching the
set value (P
set
).
External PID
controller
FC
130BA256.11
P
P
System
P
Set
f
Out
f
Ref
Illustration 3.53 Boost System
2) In systems where the pressure or temperature is
controlled by an external PI controller, the wake-up
conditions cannot be based on feedback from the
pressure/temperature transducer as the setpoint is not
known. In the example with a boost system, desired
pressure P
set
is not known. Parameter 1-00 Conguration
Mode for [0] Open Loop.
Example: Boost system.
130BA258.10
t
1
p
(Pressure)
Time
Time
No/Low Flow
detected
p
System
P
Set
Sleep mode
activated
P
Ref
= P
Wake
(Frequency)
f
Ref
f
Ref /
f
Out
f
Ref
f
Out
f
Wake
f
Out
Illustration 3.54 Boost System
When low power or low speed is detected the motor is
stopped, but the reference signal (f
ref
) from the external
controller is still monitored. Because of the low pressure
created, the controller increases the reference signal to
gain pressure. When the reference signal has reached a set
value, f
wake
, the motor restarts.
The speed is set manually by an external reference signal
(Remote Reference). Use default settings (parameter group
22-3* No-Flow Power Tuning) for tuning of the no-ow
function.
Internal PI controller
(parameter 1-00 Conguration Mode: Closed loop)
External PI controller or manual control
(parameter 1-00 Conguration Mode: Open loop)
Sleep mode Wake up Sleep mode Wake up
No-ow detection (pumps only) Yes Yes (except manual
setting of speed)
Low speed detection Yes Yes
External signal Yes Yes
Pressure/temperature
(transmitter connected)
Yes No
Output frequency No Yes
Table 3.24 Conguration Overview
NOTICE
Sleep mode does not active when local reference is
active (press the navigation keys to set speed manually).
See 3-13 Reference Site.
Does not work in Hand mode. Carry out Auto set-up in
open loop before setting input/output in closed loop.
Parameter Descriptions
VLT
®
HVAC Drive FC 102
166 Danfoss A/S © 03/2015 All rights reserved. MG11CE02
33

Danfoss Metasys N2 Specifications

General

Brand	Danfoss
Model	Metasys N2
Category	DC Drives
Language	English