Danfoss VLT Programming Guide

The feedback from the pressure transducer is monitored and when this pressure has dropped with a set percentage below the normal set point for
pressure (Pset), the motor will ramp up again and pressure will be controlled for reaching the set value (Pset).
2) In systems where the pressure or temperature is controlled by an external PI controller, the wake up conditions can not be based on feedback from
the pressure/temperature transducer as the setpoint is not known. In the example with a boost system, desired pressure Pset is not known.
Par. 1-00
Configuration Mode must be set for Open Loop.
Example: 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 and because
of the low pressure created, the controller will increase 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). The settings (parameter group 22-3*) for tuning of the No Flow function
must be set to default.
Configuration possibilities, overview:
3 Parameter Description VLT
®
HVAC Drive Programming Guide
208 MG.11.C9.02 - VLT
®
is a registered Danfoss trademark
3

Danfoss VLT Specifications

General

Frequency	50/60 Hz
Enclosure	IP20, IP21, IP55, IP66
Series	VLT
Control Technique	Flux Vector Control
Output Voltage	0-Vinput
Control Method	Fieldbus
Communication Interface	PROFIBUS, CANopen
Protection Features	Overload, Overvoltage, Undervoltage, Short Circuit, Ground Fault
Cooling Method	Liquid Cooled
Storage Temperature	-25°C to +70°C
Relative Humidity	5-95% non-condensing
Altitude	Up to 1000m (3280ft) without derating, up to 4000m (13120ft) with derating
Operating Temperature	-10°C to +50°C (14°F to 122°F)