Group
Title
Function
13-
Smart Logic Controller
Parameters used to configure the built in Smart Logic Controller (SLC), which can be used for simple func-
tions such as comparators (e.g., if running above xHz, activate output relay), timers (e.g., when a start
signal is applied, first activate output relay to open supply air damper and wait x seconds before ramping
up) or a more complex sequence of user defined actions executed by the SLC when the associated user
defined event is evaluated as TRUE by the SLC. (For example, initiate an economizer mode in a simple AHU
cooling application control scheme where there is no BMS. For such an application, the SLC can monitor
the relative humidity of the outside air, and if it is below a defined value, the supply air temperature setpoint
could be automatically increased. With the adjustable frequency drive monitoring the relative humidity of
the outside air and supply air temperature via its analog inputs and controlling the chilled water valve via
one of the extended PI(D) loops and an analog output, it would then modulate that valve to maintain a
higher supply air temperature). The SLC can often replace the need for other external control equipment.
14-
Special Functions
Parameters used to configure special functions of the adjustable frequency drive including: setting of the
switching frequency to reduce audible noise from the motor (sometimes required for fan applications);
kinetic backup function (especially useful for critical applications in semi-conductor installations where per-
formance under line power dip/line power loss is important); line imbalance protection; automatic reset
(to avoid the need for a manual reset of alarms); energy optimization parameters (which typically do not
need changing but enable fine tuning of this automatic function (if necessary) ensuring the adjustable
frequency drive and motor combination operate at their optimum efficiency at full and partial load condi-
tions) and auto-derating functions (which enable the adjustable frequency drive to continue operation at
reduced performance under extreme operating conditions ensuring maximum up time).
15-
FC Information
Parameters providing operating data and other drive information including: operating and running hour
counters; kWh counter; resetting of the running and kWh counters; alarm/fault log (where the past 10
alarms are logged along with any associated value and time) and drive and option card identification pa-
rameters such as code number and software version.
16-
Data Readouts
Read only parameters which display the status/value of many operating variables which can be displayed
on the LCP or viewed in this parameter group. These parameters can be particularly useful during com-
missioning when interfacing with a BMS via a high level interface.
18-
Info & Readouts
Read-only parameters which display the last 10 preventative maintenance log items, actions and time and
the value of analog inputs and outputs on the Analog I/O option card which can be particularly useful during
commissioning when interfacing with a BMS via a high level interface.
20-
FC Closed-loop
Parameters used to configure the closed-loop PI(D) controller which controls the speed of the pump, fan
or compressor in closed-loop mode including: defining where each of the three possible feedback signals
come from (e.g., which analog input or the BMS HLI); conversion factor for each of the feedback signals
(e.g., where a pressure signal is used for indication of flow in an AHU or converting from pressure to
temperature in a compressor application); engineering unit for the reference and feedback (e.g., Pa, kPa,
m Wg, in Wg, bar, m3/s, m3/h, °C, °F, etc); the function (e.g., sum, difference, average, minimum or
maximum) used to calculate the resulting feedback for single zone applications or the control philosophy
for multi-zone applications; programming of the setpoint(s) and manual or auto-tuning of the PI(D) loop.
21-
Extended Closed-loop
Parameters used to configure the 3 extended closed-loop PI(D) controllers which, for example, can be used
to control external servos (e.g., chilled water valve to maintain supply air temperature in a VAV system)
including: engineering unit for the reference and feedback of each controller (e.g., °C, °F, etc); defining
the range of the reference/setpoint for each controller; defining where each of the references/setpoints
and feedback signals come from (e.g., which analog input or the BMS HLI); programming of the setpoint
and manual or auto-tuning of each of the PI(D) controllers.
22-
Application Functions
Parameters used to monitor, protect and control pumps, fans and compressors including: no flow detection
and protection of pumps (including auto-setup of this function); dry pump protection; end of curve detec-
tion and protection of pumps; sleep mode (especially useful for cooling tower and booster pump sets);
broken belt detection (typically used for fan applications to detect no air flow instead of using a
∆
p switch
installed across the fan); short cycle protection of compressors and pump flow compensation of setpoint
(especially useful for secondary chilled water pump applications where the
∆
p sensor has been installed
close to the pump and not across the furthest most significant load(s) in the system; using this function
can compensate for the sensor installation and help to realize the maximum energy savings).
6 How to Program the Low Harmonic Drive
VLT HVAC Low Harmonic Drive Instruction
Manual
6-2
MG.16.A1.22 - VLT
®
is a registered Danfoss trademark
6