Suction Pressure Control; Figure 5-1. Compressor Control Screen - Suction Pressure Control - Emerson VILTER MicroVission Operation And Service Manual

Section 5 • Compressor Control

Suction Pressure Control

When the Active Control Mode is set to "Suction Pressure
SP1" or "Suction Pressure SP2"', the control setpoint is
Suction Pressure Control.
Pressure Control Setpoint
The suction pressure of the compressor to operate when
the compressor is running in Auto, Remote Auto, or
Direct I/O Auto run mode.
Load Offset
The offset value when added to the "Pressure Control"
setpoint, determines the suction pressure for loading
the compressor.
Load Interval
The time interval for which control algorithm will wait
between the steps while loading the compressor.
When the suction pressure of the compressor is equal to
or greater than the "Pressure Control" setpoint plus the
"Load Offset" value, the control algorithm loads one step
and then waits for the load interval time. Once the load
interval time is lapsed, the control algorithm will again

Figure 5-1. Compressor Control Screen - Suction Pressure Control

5 – 2
check if the suction pressure is equal to or greater than
the "Pressure Control" setpoint plus the "Load Offset"
value. If yes, MicroVission loads the next step.
Unload Offset
The offset value when removed from the "Pressure
Control" setpoint, determines the suction pressure for
unloading the compressor.
Unload Interval
The time interval for which control algorithm will wait
between the steps while unloading the compressor.
When the suction pressure of the compressor is less than
or equal to the "Pressure Control" setpoint minus the
"Unload Offset" value, the control algorithm unloads
one step and then waits for the unload interval time.
Once the unload interval time is lapsed, the control al-
gorithm will again check if the suction pressure is less
than or equal to the "Pressure Control" setpoint minus
the "Unload Offset" value. If yes, MicroVission unloads
the next step.
MicroVission Controller • Operation and Service Manual • Emerson • 35391MV 1.3