Compressor Configuration
10
Danfoss Turbocor Compressors Inc.
ECD-00007M Rev. 1
to hold the number of steps sent to the motor as
determined by the Starting Valve Position %. Value is
in seconds and starts to count down when the drive is
enabled.
5.
Enter the Control Setpoint, i.e., suction superheat or
liquid level.
(Not applicable to load balance control
mode.)
6.
Enter the Valve Control Loop Speed. This value
represents the reaction time of the control loop to a
process error and replaces the PID controller gains
(proportional, integral, and derivative).
7.
Enter the Minimum Closure During Operation. This is
the minimum close position for the valve while the
compressor is spinning.
8.
Click Next to continue. Repeat steps 1 through 7 for
electronic expansion valve # 2.
Table 3 Control Modes
Control Mode
Description
Superheat
The calculation of superheat can be based on the temperature and pressure
measurements from one of the following sources:
•
Superheat control using the compressor flange temperature and pressure (this
mode is not recommended as the temperature at the compressor flange is
influenced by external factors).
•
Superheat control using the compressor flange pressure and a 10K thermistor
that is connected to the terminals labeled “ENTRY” on the Chiller Interface
module.
•
Superheat control using the compressor flange pressure and a 10K thermistor
that is connected to the terminals labeled “LIQT” on the Chiller Interface
module.
•
Superheat control using an external temperature and pressure sensor
connected to the terminals on the IO pcb labeled “SPARE T” & “SPARE P”.
Liquid Level
Liquid level can be measured from one of the following sources:
•
Liquid Level 1 control using a level sensor connected to the terminals on the
Chiller Interface module labeled “LIQ LEV1”.
•
Liquid Level 2 control using a level sensor connected to the terminals on the
Chiller Interface module labeled “LIQ LEV2”.
For liquid level sensing, two types of level sensors can be used: a level sensor
with a supply of 15VDC and an output of 0-5VDC or a resistive-type level sensor,
0-90 Ohm. Refer to vendor documentation for wiring these types of sensors to the
Chiller Interface module.
Load Balance
The Load Balance control mode uses the compressor’s own internal control
algorithm to determine the best mix of speed control, inlet guide vane opening and
load balance valve opening. Use this mode only if a load balancing valve is
installed in the system. Since the load balancing valve is connected to the
compressor’s capacity control algorithm, selecting this mode without a valve
installed will add a delay to the loading/unloading process, i.e., the compressor will
try to open and close the valve for 2 minutes rather than close the vane or change
the speed.
