Control / Supervision Parameters - Danfoss VACON NX Commissioning And Maintenance Manual

INTRODUCTION
4.2.5 Contr ol / super vision par ameter s
When the HX-unit is working within the pre-
drives. The HX-unit supervision system is programmed to generate alarms to alert the user to a
signal to the main drive and takes them offline.
The project-specific minimum flow speed is to be set as switching point for the flow switch FTSA11.
The flow switch sends a digital signal to the HX control unit, if the flow speed drops under the preset
parameter values. If the signal is active longer than 5 seconds, the HX control unit disconnects the
The flow switch FTSA11 also sends out a temperature signal that controls the 3-way valve in the
secondary circuit. The FT
on valve V130.
The temperature parameters are adjusted at commissioning, depending on the maximum
temperature of the inlet secondary circuit liquid and the ambient temperature in the main drive
area. If the temperature drops below the set point in the primary circuit, the valve on the secondary
circuit decreases the amount of liquid going through the plate heat exchanger (HX11) in order to
increase the temperature in the primary circuit.
The temperature signal from FTSA11 also generates low- and high-temperature alarms and high-
temperature shutoff. The high-temperature alarm and shutoff functions protect the main drives
from overheating, and the low temperature alarm protects the main drives from condensation.
If the temperature goes above the high-
is disconnected. In this case, the HX-unit cooling pump continues running, but the main drive is shut

parameter is 45 C.
function of the switch is to give a signal to the HX control unit, in case there is liquid on the leakage
plate. The liquid can be from a leak in one of the circuits, or from condensation on colder pipe
surfaces due to high relative humidity of the air.
The HX-unit provides no control of the temperature or flow in the secondary
!
circuit. It is strongly recommended that the customer and/or end-user add a
temperature and flow control on the secondary circuit piping outside the HX-
unit.
NOTE
Depending on the quality of the secondary circuit liquid, the plate heat exchanger might clog and
affect the efficiency and flow of the unit. Because the primary circuit is a closed circuit, it contains
only a small amount of liquid. This means that it will react fast to changes in temperature or flow in
the secondary piping.
If the flow for some reason is shut down in the secondary circuit, the HX-unit will
!
main drive load, due to a high-temperature shutoff.
NOTE
Local contacts: http:/ / dr ives.danfoss.com/ danfoss- dr ives/ local - contacts/
mA signal, which is then sent to the actuator (FV11)
the drive is disconnected. The default setting for this
VACON 1 7
-unit. The
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