Danfoss EKC 315A Manual page 8

Manual
Regulating parameters
NOTE: Only a trained Danfoss technician should adjust settings given in the gray blocks. Misadjustment could cause serious
system malfunction.
P: Amplification factor, K
p
Increasing proportional factory Kp leads to larger changes in controller output for a given
input (regulation becomes faster). Too high a K
I: Integration time T
n
Decreasing T results in faster response to sensor value changes.
n
D: Differentiation time T
d
This setting can be turned off by setting its value to minimum (0). Increasing Td increases
controller output changes, but can lead to instability.
Maximum value for superheat reference
Minimum value for superheat reference
WARNING: Due to the risk of liquid floodback, the setting should not be lower than
approximately 4 - 7°F (2 -4°K).
MOP
If MOP function is not desired, adjust to maximum setting. MOP function limits valve
opening degree as long as evaporating pressure is higher than user-set value.
Period time for AKV and AKVA pulse valves
In most cases, this parameter should not need to be changed. This parameter determines
the length of the control period. The valve is opened for a certain percentage of each
successive period. For example, when full valve capacity is called for, the valve will be
opened for the entire period. When 60% valve capacity is required, the valve will be
opened for 60% of the period. The control algorithm computes the capacity required for
each period.
Stability factor for superheat regulation
This value should only be changed by specially trained service technicians. A higher value will
allow greater superheat fluctuation before the reference is changed.
Damping of amplification near the reference value
This value should only be changed by specially trained service technicians. This setting damps
Kp near the reference value. A setting of 0.5 will reduce Kp by half.
Amplification factor for superheat (only in 1:1 systems)
This setting determines the ICM or AKV valve's opening degree as a function of the change
in evaporating pressure. An increase in evaporating pressure will result in a lower opening
degree. When there is a drop-out on the low pressure thermostat during start-up, the
value must be raised. If there is pendling during start-up, the value must be reduced a
small amount. This value should only be changed by specially trained service technicians.
Defines superheat regulation (see Appendix 2)
1) Minimum stable superheat (MSS). Adaptive regulation.
2) (Works best for industrial refrigeration systems) Based on Load-defined superheat. The
reference is established based on the line formed by the three points: n09, n10, and n22.
Value of minimum superheat reference for loads under 10%
The value must be less than n10. The controller will force the valve closed when superheat
is below this set value.
Standby TQ valve (discontinued valve) temperature when valve closed
The TQ actuator is kept warm when the valve closes. As the closing point can not be
defined exactly due to tolerances and pressure variations, the setting can be changed as
needed to affect valve closing tightness.
Standby TQ valve (discontinued valve) temperature when valve open
The TQ actuator's temperature is kept low when the valve reaches its fully open position.
This parameter sets the number of degrees that the temperature is to be above the
expected open temperature when the valve is completely open. A greater value ensures
that the valve is open, but a greater value will also result in slower closing.
Maximum opening degree
The ICM or AKV valve's opening degree can be limited. The value is set in %. This value
should only be changed by specially trained service technicians.
Minimum opening degree
This value should only be changed by specially trained service technicians. The ICM or AKV
valve's opening degree can be set to a minimum valve that disables full closure.
8
EKC 315A Industrial Evaporator Controller
Description of setting
can cause the valve to hunt.
p
USCO.PD.RD0.A1.22 / 521U0092
Parameter Minimum Maximum
n04 0.5 20
n05 30 (sec) 600 (sec)
n06 0 (sec) 90 (sec)
4°F 90°F
n09
(2°K) (50°K)
2°F 22°F
n10
(1°K) (12°K)
0 psig 870 psig
n11
(0 bar) (60 bar)
n13 3 (sec) 10 (sec)
n18 0 10
n19 0.2 1.0
n20 0.0 10.0
n21 1 2
n22 1 15
-27°F 36°F
n26
(-15°K) (20°K)
-27°F 126°F
n27
(-15°K) (70°K)
n32 0 (%) 100 (%)
n33 0 (%) 100 (%)
© Danfoss USCO (HMR_MKS), 04-2008
Factory Field
setting setting
3.0
120 (sec)
0 (sec)
10.8°F
(6°K)
7°F
(4°K)
870 psig
(60 bar)
6 (sec)
5
0.3
0.4
1
2
0°F
(0°K)
36°F
(20°K)
100 (%)
0 (%)