070.610-IOM (JUL 21)
Page 27
RWF II Rotary Screw Compressor Units
Operation
Figure 30: Liquid injection
adjustment screen
Description:
This screen allows the user to enter and view
the operating parameters related to
EZ-Cool LIOC P
I control.
The following are the EZ-Cool LIOC Setup screen selections
available on this screen:
Liquid Injection Oil Cooling
Valve Type
• Analog Modulating
- This selection is used to control
a modulating valve that requires an analog output (4-10
mA) signal. This is the standard valve type for Frick
packages and includes valves like the Danfoss modulat
-
ing valve for LIOC.
• Digital PWM
- This selection is used to control a
modulating valve that requires a digital PWM signal. This
includes valves like the Yosaku LIOC valve.
The PWM signal is controlled from the LIOC PWM Digital
Output. To use this selection, the LIOC PWM Digital
Output must be configured in the Digital I/O section.
The PWM cycle time is 20 seconds. The Control Output
corresponds to the PWM output On time. For example,
if the Control Output value is calculated to be 75%, then
the PWM output will cycle On for 15 seconds and then
Off for 5 cycles. It will continue to repeat this cycle if the
Control Output is greater than 0%.
Solenoid control
An output is provided for an optional liquid injection sole
-
noid valve. The function of this output is only available if the
compressor has liquid injection oil cooling and it has been
enabled. Liquid injection controls the supply of liquid refrig
-
erant to the compressor. Liquid injection is off (the solenoid
is closed) if the compressor is off.
[On When Above
] - When the
Discharge Temperature
is
above this setpoint, the
Liquid Injection
solenoid output will
energize, until the
Discharge Temperature
drops below this
setpoint.
[Off When Below]
- When the
Discharge Temperature
is
below this setpoint, the
Liquid Injection
solenoid output will
de-energize, until the
Discharge Temperature
raises above
this setpoint.
EZ-Cool status
Discharge Temperature
- The actual discharge temperature
is shown here.
Control Output
- The value of the output signal as con
-
trolled by the PI. This is not a setpoint value.
Valve Position
- The value shown here represents the posi-
tion of the valve with relationship to the
Control Output
.
EZ COOL PI Control
[Setpoint]
- Enter the value that you wish to control to.
[Proportional Band]
– This setpoint determines the size of
a region either above or below the control setpoint. Within
this region, the proportional component of the PI Output
value is the number between 0% and 100% that directly
corresponds to the difference between the control input
(actual) and the control setpoint (setpoint). Outside of this
region, the proportional component is either 100% or 0%.
If the PI’s action is forward, the
Proportional Band
extends
above the Control Setpoint. If the PID’s Action is Reverse,
the Proportional Band extends below the Control Setpoint.
[Integration Time]
- This setpoint controls the influence
that the Integral component exerts on the PI Output value.
The Integral component works to push the Control Input
toward the Control Setpoint by tracking the difference be
-
tween the Control Input and the Control Setpoint over time.
High Limit
- The highest value that the output can be.
Low Limit
- The lowest value that the output can be.
I/O Board
- Select from one of the following:
•
None
•
Analog Board 1
•
Analog Board 2
I/O Channel
- Select the output channel that will be used.
Port Multiplier
– This setpoint is used for the Liquid Injec
-
tion Closed Warning safety. See this safety description in the
Warnings/Shutdowns Messages section. The port multiplier
represents the internal pressure at this port divided by the
suction pressure based on the compressor design.
Quantum
HD EZ-COOL Liquid injection adjustment procedure
ACCESSING:
Package
Liquid Injection LIOC
