Emerson Vission 20/20, Руководство по эксплуатации и обслуживанию

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6 – 1
Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 2.0
Section 6 • Compressor Control
Figure 6-1. Compressor Control Screen - Suction Pressure Control
Overview
The compressor control screen is where an operator
can set the majority of the compressor settings. These
setting de
fi ne how the compressor will operate and re-
spond to changing loads. The compressor control screen
consists of several screens but in order not to overwhelm
the operator with options, many of the screens may not
be visible.
NOTE
How the compressor is con fi gured in the
con fi guration screen (Section 19) will determine
what compressor control pages are displayed.
It is important to note that there isn’t one correct way to
set these parameters. Every application is different and
requires the operator to tune these settings to achieve
the best operation.
Suction Pressure Control and Process
Temperature Control
The Vission 20/20 uses a pulse proportional control
method to control the compressor capacity slide valve
in order to maintain the control setpoint. The control
setpoint can either be process temperature control set-
point or suction pressure control setpoint depending on
what the operator has selected as the control mode. For
screens, see Figure 6-1 and Figure 6-2.
The proportion control uses the Interval Time Setpoint
to de
fi ne the time the algorithm waits to read the cur-
rent setpoint and calculates the error from the process
control setpoint. Based on the error from setpoint, the
algorithm calculates a pulse time in which the capacity
slide is moved in the direction of the error. The further
away the process variable is from the control setpoint,
the larger the corrective pulse will be. The duration of
the pulse is limited by the Pulse Time Setpoint. By de-
fault the maximum pulse time is the same as the inter-
val time. This means that the pulse time can be 100% of