Danfoss VT2800 Series, Design Manual

Page: 99 / 162

VLT
®
2800 Series
Programming
416 Process units
(REF/FEEDB. UNIT)
Value:
✭
No unit (NO UNIT)
[0]
% (%)
[1]
ppm (PPM) [2]
rpm (RPM) [3]
bar (BAR) [4]
Cycles/min (CYCLE/MI)
[5]
Pulses/s (PULSE/S)
[6]
Units/s (UNITS/S) [7]
Units/min. (UNITS/MI) [8]
Units/h (UNITS/H) [9]
°C (°C)
[10]
Pa (PA)
[11]
l/s (L/S) [12]
m
3
/s (M
3
/S) [13]
l/min. (L/M) [14]
m
3
/min. (M
3
/MIN)
[15]
l/h (L/H)
[16]
m
3
/h (M
3
/H) [17]
Kg/s (KG/S) [18]
Kg/min. (KG/MIN) [19]
Kg/hour (KG/H)
[20]
Tons/min. (T/MIN)
[21]
Tons/hour (T/H) [22]
Metres (M) [23]
Nm (NM) [24]
m/s (M/S)
[25]
m/min. (M/MIN)
[26]
°F (°F) [27]
In wg (IN WG) [28]
gal/s (GAL/S) [29]
Ft
3
/s (FT
3
/S)
[30]
Gal/min. (GAL/MIN)
[31]
Ft
3
/min. (FT
3
/MIN) [32]
Gal/h (GAL/H) [33]
Ft
3
/h (FT
3
/H) [34]
Lb/s (LB/S)
[35]
Lb/min. (LB/MIN)
[36]
Lb/hour (LB/H) [37]
Lb ft (LB FT) [38]
Ft/s (FT/S) [39]
Ft/min. (FT/MIN)
[40]
Function:
Select among different units to be shown on the
display. The unit is read out if an LCP control
unit can be connected, and if Reference [unit] [2]
or Feedback [unit] [3] has been selected in one
of parameters 009-012 Display read-out , and in
Display mode. The unit is used in Closed loop
also as a unit for Minimum/Maximum reference
and Minimum/Maximum feedback.
Description of choice:
Select the required unit for the reference/feed-
back signal.
■
VLT 2800 Regulators
The VLT 2800 has two integrated PID regulators, one
to regulate speed and one to regulate processes.
Speed regulation and process regulation require
a feedback signal back to an input. There are a
number of settings for both PID regulators that are
made in the same parameters, but selection of
regulator type will affect the selections that have
to be made in the shared parameters.
In parameter 100 Configuration it is possible to select
regulator type, Speed regulation, closed loop [1]
or Process regulation, closed loop [3].
Speed regulation
This PID regulation is optimised for use in applications
in which there is a need to maintain a particular motor
speed. The parameters that are specific for the speed
regulator are parameter 417 to parameter 421.
Process regulation
The PID regulator maintains a constant process
mode (pressure, temperature, flow, etc.) and
adjusts the motor speed on the basis of the
reference/setpoint and feedback signal.
A transmitter provides the PID regulator with a
feedback signal from the process as an expression
of the process ’ s actual mode. The feedback signal
varies as the process load varies.
This means that there is a variance between the
reference/setpoint and the actual process mode.
This variance is compensated by the PID regulator
by means of the output frequency being regulated
up or down in relation to the variance between the
reference/setpoint and the feedback signal.
The integrated PID regulator in the frequency converter
has been optimised for use in process applications.
This means that there are a number of special
functions available in the frequency converter.
Previously it was necessary to obtain a system
to handle these special functions by installing
extra I/O modules and programming the system.
With the frequency converter the need to install
extra modules can be avoided. The parameters
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.E9.02 - VLT is a registered Danfoss trademark
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