Danfoss EKC 347 User Manual
Liquid level controller
EKC 347
Manual
Introduction
Application
The controller is used for regulation of the refrigerant level in:
• Pump reservoirs
• Separators
• Intermediate coolers
• Economisers
• Condensers
• Receivers
System
A signal transmitter will constantly measure the refrigerant liquid
level in the reservoir - the controller will receive the signal and
subsequently control the valve, in order to control the refrigerant
liquid level according to liquid level setpoint.
Signaltransmitter
With the capacitive rod it is possible to set the refrigerant level
within a wide range.
EKC 347
The controller receive a signal and are then able to contol
low or high side applications. A analog input signal (voltage/
current) can displace the setpoint and then remote change of
setpoint is thus possible.
EKC 347 does support 2 types of Danfoss expansion valves. (see
below)
One analog input is available as feed back from ICM in order to
indicate Opening degreee of the ICM.
Expansions valve
Two types of Danfoss expansion valves can be used
ICM - ICM are direct operated motorized valves driven by
digital stepper motor type ICAD
AKV/A - AKVA or AKV are pulse-width modulating expansion
valves.
Functions
• Liquid level control
• Alarm if the set alarm limits are exceeded
• Relay outputs for upper and lower level limits and for alarm level
• Analog input signal which can displace the reference
• PI control
• Low or High side control
• When AKV/A is selected, a MASTER/SLAVE system can run up to 3
AKV/A with distributed Opening Degree
• Manual control of output
• Limitation of Opening degree possible
• ON/OFF operation with hysteresis
Extra options
• PC operation
The controller can be provided with data communication, so
that it may be hooked up with other products in the ADAPKOOL® range of refrigeration controls. Operation, moni toring
and data collection can then be performed from a PC - either in
situ or at a service company.
LED's on front panel
All
Opening signal to valve
Indication of upper level limit
Indication of lower level limit
Indication of alarm level
EKC 347
2 Manual RS8AX702 DKRCC.ES.R1.A1.02/ 520H4020 © Danfoss 01-2011 EKC 347
Application examples
Pump reservoir
Modulating control of injection makes for a more stable liquid
level and suction pressure.
Separator on flooded evaporator
Modulating control and the valve’s large capacity range ensure a
stable level - even under conditions of quickly changing loads.
Intermediate cooler
The level transmitter’s wide measuring range enables it to monitor
the liquid at all levels of the reservoir - and hence to use the signal
for safety functions in connection with the max. permissible level
Receiver / condenser
The control system’s short reaction time makes it very suited for
high-pressure oat systems with small refrigerant charges.
EKC 347 Manual RS8AX702 DKRCC.ES.R1.A1.02/ 520H4020 © Danfoss 01-2011 3
Survey of functions
Function Para-
meter
Normal display Level control
The liquid level is indicated in %
The % value is calculated on the basis of the input signal and the denition in ”o31”.
The valve’s actual opening degree can be displayed by giving the lower button a brief
push (1s). Cf. also o17.
Reference
Set point
Regulation is based on the set value provided that there is no external contribution
(o10).
(Push both buttons simultaneously to set the setpoint).
External contribution to the reference
This setting determines how large a contribution is to be added to the set reference
when the input signal is max (20 mA or 10 V. Cf. also o10).
The value is set in %-points.
Start/stop of regulation
With this setting the level regulation can be started and stopped. Start/stop of level
regulation can also be performed with the external contact function. Regulation is
stopped if just one of them is OFF.
Alarm Level Alarms
The controller can give alarm in dierent situations.
When there is an alarm the three lowest LED’s at the front of the controller will ash,
and the alarm relay is cut in
Limit for upper level
Here you set the limit value for the upper level indication. The value is set in %. The
relay for the upper level will become activated when the level exceeds the set value.
Limit for lower level
Here you set the limit value for the lower level indication. The value is set in %. The relay for the lower level will become activated when the level drops below the set level.
Time delay for upper level limit
When the limit value is exceeded a timer function will start. The relay will not become
activated until the set time delay has been passed. The time delay is set in seconds.
Delay for lower limit level
When the limit value is exceeded a timer function will start.The relay will not become
activated until the set time delay has been passed.
The time delay is set in seconds.
Limit for alarm level
An alarm level can be set which when passed will activate the alarm relay- The value is
set in %. Cf. also the denition in A18.
If the limit alarm (A3) is not required, it can be avoided by means of the following set-
ting in A16:
100 : If the rising level denition has been chosen. (A18=0 or 2)
0: If the falling level denition has been chosen. (A18=1 or 3)
Time delay for alarm level
When the alarm level is exceeded a timer function will start. The relay will not become
activated until the set time delay has been passed.
The time delay is set in seconds.
Parameter by operation via
data communication
- Liquid level
- OD %
- SP Liquid Level
r06 r06 Ext. Ref.oset
r12 r12 Main Switch
A01 A01 Upper Dev.
A02 A02 Lower Dev.
A03 A03 Upper Delay
A15 A15 Lower Delay
A16 A16 Limit Alarm
A17 A17 Limit Delay
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Configuration of limit alarm (A3) level and lower limit alarm(A2) for pump cut-
A18 A18 Lim. LowMode
out.
To dene whether the limit alarm (A3) is linked to rising (A18=0) or falling level
(A18=1).
It is also possible to congurate the Relay for lower level limit when lower limit alarm
(A2) is detected. Dedicated to switch o pumps at low level alarm.
0: Rising level. When liquid level is higher than A16, and time in A17 has expired, A3
alarm is generated.
1: Falling level . When liquid level is lower than A16, and time in A17 has expired, A3
alarm is generated.
2: Same function as if A18=0, but in addition (to that:
- When liquid level is higher than A02. No A2 alarm and Relay for lower level limit,
gives ON signal (cut in) on terminal 8 and 10.
- When liquid level is lower than A02 and time in A15 has expired. A2 alarm is generated and Relay for lower level limit, gives OFF signal (cut out) on terminal 8 and 10.
3: Same function as if A18=1, but in addition (to that:
- When liquid level is higher than A02. No A2 alarm and Relay for lower level limit,
gives ON signal (cut in) on terminal 8 and 10.
- When liquid level is lower than A02 and time in A15 has expired. A2 alarm is generated and Relay for lower level limit, gives OFF signal (cut out) on terminal 8 and 10.
Function Alarm relay when A1, A2 or A3 alarms are detected.
0: Alarm relay to be activated when A1 or A2 or A3 are detected.
1: Alarm relay only to be activated when A3 is detected.
A19 A19 Alarm type
(With setting = 0 the alarm is also
transmitted via the data communication)
Alarm relay
The alarm relay will become activated if one of the set limits is exceeded or if the
controller loses the input signal from the level-measuring unit.
With data communication the importance of the individual alarms can be
dened. Setting is carried out in the
“Alarm destinations” menu. See also
page 11.
Control parameters Injection Settings
Definition of regulating principle
n35 n35 Low/High Pr.
Here you set whether the controller is to open or close the valve when the liquid level
is rising.
Low (0): Regulation on the low-pressure side. The valve closes when liquid level is
rising.
High (1): Regulation on the high-pressure side. The valve opens when liquid level is
rising.
Period time
n13 n13 AKV per.time
An AKV/A valve is operated with pulses of a given length. The length depends on the
opening degree required. If a large opening degree is required, the pulse will last for
an entire period time. A period time will thus comprise both open and closed valve.
P - band
n04 n04 P-band
If the value is reduced the regulating range will be reduced. (The P-band will be near
the reference).
I: Integration time Tn
n05 n05 Tn sec.
The I-link can be made passive by setting the value at max. (600s)
(If the Tn value is increased the regulation becomes slower).
Neutralzone
n34 n34 Neutralzone
The function is only active if the selected expansion valve is of type ICM
Min. opening degree
n33 n33 OD Min.
Here you can make a setting if you require a limitation of the valve’s working range.
Max. opening degree
n32 n32 OD Max.
Here you can make a setting if you require a limitation of the valve’s working range.
EKC 347 Manual RS8AX702 DKRCC.ES.R1.A1.02/ 520H4020 © Danfoss 01-2011 5
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