Danfoss VLT Programming Guide

This means that any normal stop command can be overridden by the Minimum Run Time function (par. 22-77 Minimum Run Time ) and any normal start
command (Start/Jog/Freeze) can be overridden by the
Interval Between Starts function (par. 22-76 Interval between Starts ).
None of the two functions are active if
Hand On or Off modes have been activated via the LCP. If selecting Hand On or Off , the two timers will be reset
to 0, and not start counting until
Auto is pressed and an active start command applied.
NB!
A Coast command or missing Run Permissive signal will override both Minimum Run Time and Interval Between Starts functions.
22-75 Short Cycle Protection
Option: Function:
[0] * Disabled Timer set in par. 22-76 Interval between Starts is disabled.
[1] Enabled Timer set in par. 22-76
Interval between Starts is enabled.
22-76 Interval between Starts
Range: Function:
Application
dependent*
[Application dependant] Sets the time desired as minimum time between two starts. Any normal start command (Start/Jog/
Freeze) will be disregarded until the timer has expired.
22-77 Minimum Run Time
Range: Function:
0 s* [Application dependant] Sets the time desired as minimum run time after a normal start command (Start/Jog/Freeze). Any
normal stop command will be disregarded until the set time has expired. The timer will start counting
following a normal start command (Start/Jog/Freeze).
The timer will be overridden by a Coast (Inverse) or an External Interlock command.
NB!
Does not work in cascade mode.
3.20.7 22-8* Flow Compensation
It is sometimes the case that is not possible for a pressure transducer to be placed at a remote point in the system and it can only be located close to
the fan/pump outlet. Flow compensation operates by adjusting the set-point according to the output frequency, which is almost proportional to flow, thus
compensating for higher losses at higher flow rates.
H
DESIGN
(Required pressure) is the setpoint for closed loop (PI) operation of the frequency converter and is set as for closed loop operation without flow
compensation.
It is recommended to use slip compensation and RPM as unit.
3 Parameter Description VLT
®
HVAC Drive Programming Guide
212 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)