ABB ACS320 series, Supplemental Manual

Page: 14 / 16

ABB VARIABLE FREQUENCY DRIVES
RENEWAIRE.COM ABB VFD SUPPLEMENTAL MANUAL 1.800.627.4499 14
SETTINGS
OPERATION
SCALING AND RESPONSE TO ANALOG INPUTS
The most likely reason to control the VFD from
an analog signal is to automatically change the
amount of outside air ventilation to meet the actual
needs for each time period.
If one or both of the VFDs will be controlled by an
analog input from an external Control Device (e.g. a
CO2 controller or a Building Management System),
you may need to “scale” the rate of response of the
VFD(s) to the rate of change of the analog signal.
We need to introduce two concepts relating to the
amount of outside air ventilation needed in the building:
• The “ACTION LEVEL” is the level of measurement
of indoor air quality or occupancy at which
the ERV should start to deliver more than the
“Design Minimum Supply Airfl ow”;
• The “MAXIMUM RESPONSE LEVEL” is the level of
measurement of indoor air quality or occupancy
at which the ERV should be operating at the
“Design Maximum Supply Airfl ow”.
Do not change PARAMETER 2003 MAX CURRENT from RenewAire default setting, which should be set
to no more than 125% of the motor nameplate FLA for motors with 1.15 Service Factor (SF) or higher
or 115% of the motor FLA for motors with less than 1.15 SF and otherwise unprotected. This parameter
controls the Motor OVERLOAD PROTECTION provided by the VFD.
DANGER OF MOTOR OVERLOAD LEADING TO SMOKE AND FIRE!
WARNING
F9
SCHEMATIC RELATIONSHIP EXAMPLE BETWEEN MEASUREMENT BY A CONTROLLER, THE ANALOG
SIGNAL FROM THE CONTROLLER, THE VFD SCALING PARAMETERS AND THE MOTOR SPEED
(VFD OPERATING FREQUENCIES).
0 2000
4mA 20mA
0vdc 10vdc
ACTION LEVEL
MAXIMUM RESPONSE LEVEL
1104 "REF1 MIN"
MEASURED CONDITION
ANALOG SIGNAL FROM
CONTROLLER
0hz
60hz
10hz
20hz
30hz
40hz
50hz
500 1000 1500
1105 "REF1 MAX"
LEVEL AT MAXIMUM DEVICE OUTPUT
(CO
2
CONCENTRATION IN THIS EXAMPLE)
1301 MINIMUM AI1
in this example = 55%"
1302 MAXIMUM AI1
in this example = 91%"
0