Emerson Vilter MicroVission - Step Control

21 – 4
Section 21 • Condenser Control
MicroVission Controller • Operation and Service Manual • Emerson • 35391MV 1.3
Step Control
The Step Control allows the operator to setup the man-
ner in which Fans, Pumps & VFD will be turned on/off.
Fans & Pumps are connected on digital outputs Out #1
to Out #4. VFD Fan is connected on Analog Output. Each
step can have a maximum of ve outputs connected to
it. Each step can be opted in or out depending on en-
abling of checkbox.
When Run Mode is Auto and condenser pressure rises
above the upper dead-band, the condenser step incre-
ments from Step 1 up to Step 5 and hence switching on/
off Pumps, Fans & VFD connected on outputs. This holds
true when decreasing steps from Step 5 to Step 1 when
condenser pressure falls below the lower dead-band.
Step Delay
Allows operator to set time delays between condenser
steps. Condenser Pressure must be outside upper or
lower dead-band continuously for delay time to increase
or decrease condenser steps.
While in a VFD step, an additional step can only be added
once VFD has reached its maximum speed setpoint and
after that the delay timers are satised. Similarly in a VFD
step, a step can only be removed once VFD has reached
its minimum speed setpoint and after that the delay tim-
ers are satised.
Low Speed Fan
Allows steps to have option for time delay in case of fan
spin down. Any of Out #1 to Out #4 can be selected as
Low Speed Fan through combo box. For current step,
The Low Speed Fan delay will only be considered if that
output was not already ON and the current step number
is Lower than the Previous Step Number. E.g.: Let’s say
Out #2 is selected as Low Speed Fan in Step 2. Before en-
tering Step 2 if the step in execution was Step 3, 4 or 5,
then when entered in Step 2 (Automatically or Manually)
if the output selected as Low Speed Fan was Off then
that output will turn on only after High to Low Speed Fan
delay is satised unlike other outputs selected in that
step turns on immediately once entered in that step. If
the Previous Step in execution was Step 1 or we directly
started from Step 2, then the High to Low Speed Fan de-
lay will not be considered and that output will turn ON
immediately once entered in that step.
The step delay timer will only start timing once the High
to Low Speed Fan delay is satised. Note that, if the out-
put selected as Low Speed Fan was already on then High
to Low Speed Fan delay will not get considered.
Control
Toggle any of the steps On/Off during Manual operation
of Condenser Control. This button is active only when
Run Mode selected is Manual. During Auto operation of
Condenser Control, control button for active step will be
“ON”.
NOTE
In case of automatic or manual prole switch
if the step which was executing in previous prole
is enabled in current prole then it will continue its
execution otherwise if that step is not enabled in
current prole then if higher step is available then
condenser control will increment the step, otherwise
if higher step is not available then condenser control
will decrement the step.