Danfoss EKD 316, EKD 316C Data sheet
Data sheet
Superheat Controller
Type EKD 316 and EKD 316C
EKD 316 / EKD 316C is a superheat controller for
the stepper motor valve that can be used where
there are requirements for accurate control of
superheat in connection with refrigeration.
The controller and valve can be used where
there are requirements for accurate control of
superheat in connection with refrigeration.
Applications:
• Processing plant (water chillers)
• Cold store (air coolers)
• A/C plant
• Heat pumps
• Air conditioning
Benets • The superheat is regulated to the lowest
possible value.
• The evaporator is charged optimally – even
when there are great variations of load and
suction pressure.
Main features
• Regulation of superheat
• MOP function
• ON/OFF input for start/stop of regulation
• Relay output to alarm
• Energy savings – the adaptive regulation of
the refrigerant injection ensures optimum
utilisation of the evaporator and thus a high
suction pressure.
• MOD bus communication
• Safety features and
• Alarm indications
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 1
Data sheet | Superheat controller type EKD 316, EKD 316C
Contents Pages
Applications..................................................................................................................................................3
Function overview ..........................................................................................................................................3
Data ...........................................................................................................................................................4
Ordering ......................................................................................................................................................4
Dimensions ..................................................................................................................................................4
Accessories ...................................................................................................................................................4
Related products ............................................................................................................................................4
Connections .................................................................................................................................................5
Conguration ................................................................................................................................................6
Parallel Evaporators with common suction line .........................................................................................................7
Data communication .......................................................................................................................................8
Installation ...................................................................................................................................................9
Installation sensors ........................................................................................................................................ 10
Start of controller.......................................................................................................................................... 11
Settings and checks to be made before start .......................................................................................................... 11
Stepper motor valve type ................................................................................................................................ 12
Operation .................................................................................................................................................. 13
Types of regulation ........................................................................................................................................ 14
Manually operating the valve ............................................................................................................................ 15
Finding the optimum settings ........................................................................................................................... 16
If the superheat uctuates ............................................................................................................................... 16
Troubleshooting ........................................................................................................................................... 17
Alarms ...................................................................................................................................................... 17
Appendix I.................................................................................................................................................. 18
- Menu survey EKD 316 ............................................................................................................................ 18 - 19
- Survey of functions .......................................................................................................................... 20 - 21 - 22
Appendix II ................................................................................................................................................. 23
- General information to MODBUS communication via a PLC etc. ................................................................................ 23
- EKD 316 – Parameter identication (modbus) ..................................................................................................... 24
- EKD 316C – Parameter identication (modbus) .............................................................................................. 25 - 26
- Installation considerations ............................................................................................................................ 27
List of literature ............................................................................................................................................ 27
Acronyms and abbreviations used in this manual:
LOC Loss of charge indication
SH Superheat
MOP Maximum operating pressure
MSS Minimum stable superheat
PNU Parameter number
Te Saturated suction temperature
Pe Evaporator pressure
S2 Evaporator temperature
S4 Evaporator outlet temperature
OD Opening degree
EEV Electronic expansion valve
∆Tm Temperature dierence between media temperature and evaporating temperature
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 2
Data sheet | Superheat controller type EKD 316, EKD 316C
Applications
The following gives an idea of the application scope of the
EKD 316 / EKD 316C controller.
Water chiller using direct expansion
The most common application is water chillers using direct
expansion. The regulation can be single loop using an AKS 32R
pressure transmitter to measure evaporator pressure and an S2
sensor to measure superheated gas. If double loop regulation is
used, the S4 sensor should be located at the water outlet pipe to
measure the leaving water temperature. It is recommended to
start with factory settings.
The application diagram shows the use of EKD 316 as a superheat
controller, where temperature sensor AKS 21A and pressure
transmitter AKS 32R have been shown as an example.
Function overview
Minimum Stable Superheat (MSS)
The controller will search for the minimum stable superheat
between an upper and lower boundry. If the superheat has been
stable for a period, the superheat reference is decreased. If the
superheat becomes unstable, the reference is raised again. This
process continues as long as the superheat is within the bounds
set by the user. The purpose of this is to search for the lowest
possible superheat that can be obtained while still maintaining a
stable system. The superheat reference can also be xed, in which
case this function is disabled.
Maximum Operating Pressure (MOP)
In order to reduce the strain of the compressor, a maximum
operating pressure can be set. If the pressure comes above this
limit, the controller will control the valve to provide a lower
pressure instead of a low superheat. The limit for this function
is usually a xed pressure, but it is possible to oset the limit
temporarily.
Stand-alone function
EKD 316 / EKD 316C is designed to operate in conjunction with a
system master controller, which will control the EKD 316 /
EKD 316C via MODBUS or analog signal. It is however possible
to use it in a standalone mode using one temperature and one
pressure transducer.
Manual Control as a valve driver
The valve can be controlled manually by setting the desired
operating degree using MODBUS. Alternatively, the controller may
also be started and stopped externally using the analog signal 4 to
20 mA/0 to 10 V DC, /1 to 5 V DC.
Forced opening during startup
In some applications it is necessary to open the valve quickly when
the compressor turns on to prevent suction pressure becoming
too low. This is ensured by setting a xed opening degree and
a startup time for the controller. Note that this will give a xed
opening degree for the duration of the start time, regardless of the
superheat value.
Relay
The relay for the alarm function is an alternating relay. In the event
of an alarm, the relay will close, which may, for instance, be used
for an alarm buzzer.
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 3
Data sheet | Superheat controller type EKD 316, EKD 316C
Data
Compatible valves
EKD 316 C
Compatible valves
EKD 316
Supply voltage
Power consumption
Input signal
*)Ri: mA: 400 ohm
V: 50 kohm
Sensor input 2 pcs. Pt 1000 ohm
Alarm relay 1 pcs. SPDT, Max 24V, 1A resistive - Class II
Step motor output
Data communication RS 485 Modbus data communication
Environments
Enclosure IP 20
Weight 300 g
Montage DIN rail
Operation
Approvals
ETS / CCM / CCMT 0 - 42 / CTR / ETS 6 /
ETS C / KVS C
ETS / CCM / CCMT 0 - 42 / CTR / ETS 6
ETS / KVS / CCM / CCMT 2 - CCMT 8
24 V AC / DC ±15% 50/60 Hz, 10 VA / 5 Watt
ETS 6 / CCMT 16 - CCMT 42:
24 V AC / DC ±15% 50/60 Hz, 15 VA / 8 Watt
(the supply voltage is not galvanically
separated from the input and output signals)
Controller
ETS step motor
Current signal * 4 - 20 mA or 0 - 20 mA
Voltage signal * 0 - 10 V or 1 - 5 V
Pressure transmitter AKS 32R
Digital input from external contact function
EKD 316 : Switching 30 - 300 mA RMS
EKD 316C : Switching 30 - 600 mA RMS
0 to +55°C, during operations
-40 to +70°C, during transport
20 - 80% Rh, not condensed
No shock inuence/vibrations
External display type EKA 164A or AK-ST via data
communication and system unit
EU Low Voltage Directive and EMC demands re. CEmarking complied with.
LVD-tested acc. to EN 60730-1 and EN 60730-2-9
EMC-tested acc. to EN50081-1 and EN 50082-2
5 VA
1.3 VA
DI : < 800 ohm = ON
DI : > 30 kohm = OFF
Ordering
Type Function Code no.
EKD 316C
EKD 316
EKA 164A
EKA 183A Programming key 084B8582
Superheat controller
(with terminals)
Superheat controller
(with terminals)
External display
(with MODBUS communication)
For technical details please see
literature reference on last page.
084B8045
084B8040
084B8563
Dimensions [mm]
Battery backup
Max. distance between
controller and valve
If battery backup is used, the requirements for the
battery are: 18 - 24 V DC See also page 12.
30 m
Related products
Pressure transducer Temperature sensor External display Programming key
AKS 32R, NSK AKS 21, AKS 11 EKA 164A EKA 183A
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 4
Data sheet | Superheat controller type EKD 316, EKD 316C
Connections
Necessary connections
Terminals:
1-2
3-4 Battery (the voltage will close the ETS valve if the
5-8 Supply to stepper motor
9-13 Operation via data communication
20-21 Switch function for start/stop of regulation.
Application-dependent connections
Superheat control
Supply voltage 24 V AC / DC
controller losses its supply voltage).
The battery voltage must not be connected from terminals 1
and 2.
EITHER EKA 164A OR System unit + software.
It is important that the installation of the data communication
cable be done correctly.
For further information on data communication: see literature
list page 23
Note:
If a switch is not connected, terminals 20 and 21 must be short
circuited.
14-15 Pt 1000 sensor at evaporator outlet (S2)
15-16 Pt 1000 sensor for measuring air temperature (S4)
17-19 Pressure transmitter type AKS 32R
Note:
The signal can not be shared with other controllers
A dedicated transformer must be used.
24V 18V
Class II
Danfoss
84B3201.10
Control of the valves opening degree with analog signal
21-22 Current signal or voltage signal from other regulation
(Ext. Ref.)
24-26 Alarm relay
There is connection between 24 and 26 in alarm situa tions.
Warning
Any external connection with grounding could create a ground
loop through a diode in the rectier bridge which could destroy
the power supply in EKD 316 / EKD 316C.
1,2 3,4 21,22
Connection to earth will destroy the controller
Connections EKD 316 Connections EKD 316 C
ETS / KVS / CCMT2 CCMT42 / CCM / CTR
White 5 White 5
Black 6 Black 6
Red 7 Red 7
Green 8 Green 8
Connections EKD 316 /
Connections EKD 316 C
ETS 6 / CCMT 0 - CCMT 1
Orange 5
Yellow 6
Red 7
Black 8
ETS C / KVD C / ETS / KVS
/ CCMT2 - CCMT42 / CCM
/ CTR
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 5
OD
Data sheet | Superheat controller type EKD 316, EKD 316C
Conguration
Independent superheat regulation
The superheat in the evaporator is controlled by one pressure
transmitter P and one temperature sensor S2. This can be done
setting o61 = 2.
Fitting the "S4" temperature sensor is optional, but the regulation
is improved by an "inner loop control" when the sensor is tted.
Function Parameter Value
Application Mode – superheat regulation o61 2
Selection of normal control mode 056 1
Valve driver (Via Analog Signal)
This is where the controller receives signals from another
controller, after which it controls the valve’s opening degree.
The signal can either be a current signal or a voltage signal.
The valve can be any of the stepper motor valves listed on “valve
overview”.
Details can be found on the section “valve overview”.
I/V
Function Parameter Value
Application Mode – superheat regulation o61 2
Selection of inner loop control mode 056 2
We recommend this inner loop control application mode setting, if
the superheating is to be regulated with precision. Here the S4 and
T0 temperature are part of an inner loop control.
The regulation algorithms require that a temperature sensor be
tted in the chilled medium.
The temperature sensor is connected to input "S4" and mounted
in the chilled medium after the evaporator. (Danfoss calls a sensor
S4 when it is mounted in the refrigerant after the evaporator).
External start/stop of regulation
The controller can be started and stopped externally via a contact
function connected to input terminals 20 and 21. Regulation is
stopped when the connection is interrupted. The function must
be used when the compressor is stopped. The controller then
closes the ETS valve so that the evaporator is not charged with
refrigerant.
Battery
For safety reasons the liquid ow to the evaporator must be cut
o if there is a power failure to the controller. As the ETS valve
is provided with a stepper motor, it will remain open in such a
situation. When mounting the battery backup, the valve will close
in the event of a power cut.
I/V
Danoss
84B2966.12
Danfoss
84B2707.10
I/V
Parameter Value Function
o61 1 Application Mode - control via analog signal
Relays
The relay for the alarm function is an alternating relay.
In the event of an alarm the relay will close to connect terminals 24
and 26. This can, for instance, be used for an alarm buzzer. When
there is no alarm or the controller is o, terminals 24 and 25 are
connected.
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 6
Data sheet | Superheat controller type EKD 316, EKD 316C
Parallel Evaporators with common suction line
Since the introduction of EEV, it has been observed the
phenomena the so-called Sleeping Evaporators phenomena have
been observed. This happens when the outlet of the evaporators
has a common suction line.
This is seen when using the Adaptive superheat Mode in some of
the controllers. What happens is that by controlling using the same
superheat reference in both controllers, evaporator No. 1 might be
controlling in the correct manner, but the EEV for evaporator No. 2
might be closed.
However, the measured superheat of controller No. 2 will be the
same as No. 1 because both S2 sensors will measure the same
temperature.
In other words, the open degree of the EEV integrates down to 0%
but, the measured superheat complies with the reference valve.
One solution is to use the Load-dened superheat Mode in the
controller because the measured superheat governs the opening
degree of the connected EEV.
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 7
EKD 316
Danfoss
84B3082.10
Data sheet | Superheat controller type EKD 316, EKD 316C
Data communication
Data communication with the EKD 316 is possible using one of the
following two ways:
• 1. Via External display (EKA 164A)
• 2. Via standard MODBUS Device
Via external display (EKA 164A)
Use an external display to operate the controller. This must be
done as follows:
Note:
Max. distance between controller and
display is 30 m.
The supply voltage to the display must be
maintained at 12 V +/- 15%.
The values are shown in three digits, and with a setting you
can determine whether the temperature is shown in °C or in °F.
(Pressure in bar or psig.)
In order to change a setting, the upper and lower buttons will
give you a higher or lower value depending on the button you
are pushing. But before you change the value, you must have
access to the menu. You obtain this by pushing the upper button
for a couple of seconds – you will then enter the column with
parameter codes. Find the parameter code you want to change
and push the middle button until the value for the parameter is
shown. When you have changed the value, save the new value by
pushing once more on the middle button.
By pushing the middle button you go directly to the Main Switch
setting (r12).
Example
Set a menu
1. Push the upper button until a parameter is shown
2. Push the upper or the lower button and nd the parameter you
want to change
3. Push the middle button and the value is shown
4. Push the upper or the lower button and select the new value
5. Push the middle button again to conclude the setting
Via standard MODBUS device
Communication direct to MODBUS RTU protocol.
There are 3 dierent MODBUS baud rates available, which are
9,600 baud, 19,200 baud and 38,400 baud.
The default MODBUS baud rate is 19,200 baud.
A scan is performed once the EKD 316 / EKD 316C controller is
connected to the network. This will auto detect the baud rate
used by the master and will automatically adjust to its setting. This
process usually take a few seconds.
The only available xed communication settings are 8 data bit,
EVEN parity and 1 stop bit.
The default unit address is 240 which, can be changed using
parameter "03 unit address".
EKD 316 can be operated from a PC that has AK-ST software
loaded.
System unit
Communication from a third party controller or monitoring
system
Settings and values can be read from the EKD 316 / EKD 316C via
MODBUS. However, the sensor values are from the local sensors
and software has not been developed to receive values from
another source.
A data list of EKD 316 parameters is provided in Appendix II and
the data for EKD 316C you can nd it in the installation guide
DKRCC.PI.RR0.A1.02
Please note that it is not possible to connect the EKA 164A
universal display in this conguration.
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 8
Data sheet | Superheat controller type EKD 316, EKD 316C
Installation
The EKD 316 / EKD 316C is normally mounted on a DIN rail, and
the necessary connections are shown in the diagram. If the sensor
S4 is not used to measure air temperature in connection with
thermostat function or as part of the controlling loop, then it is
not necessary to connect the S4 sensor. The 18-24 V battery input
at terminals 15 and 16 is not required if battery back-up is not
needed.
Power supply considerations
The terminals 1 and 2 for the voltage supply are not isolated
from the rest of the controller terminals. This means care should
be taken when connecting two or more controllers to the same
voltage supply. In the example below, the two controllers are
connected to the same voltage supply and on the input side,
terminals 21 (Analogue Input) are connected to each controller
and similarly terminals 22 (GND).
This way of connecting the controllers can cause damage and
should be avoided.
Note:
The same applies to other signal inputs e.g. terminals 2 and 4.
See warning page 5.
Stepper motor output
After installation the following checks can be made to the
connection between the EKD 316 controller and the stepper
motor of the ETS 6 / ETS valve.
With the power o, check that resistance between terminals 5 and
6 and terminals 7 and 8 is approximately:
ETS 6 / CCMT 0 : 46 Ohm
CCMT 1 : 31 Ohm
ETS / KVS / CCMT 2 - CCMT 8 / CCM : 53 Ohm
CCMT 16 - CCMT 42: 29 Ohm
ETS C / KVS C : 10 Ohm.
Make slight allowances for cable resistance.
If resistance values dier from above, ensure that the cable is
properly connected to the actuator of the stepper motor valve.
1. With the power on and parameter o18 set to 1, measure the
phase current from terminal 5 (or 6) and terminal 7 (or 8 ) with
a true RMS multimeter when the valve is operating. The valve
can be driven from 0% to 100% and vice versa by changing
the valve opening percentage in parameter o45. The phase
current should be 100 mA rms (for ETS) when operating.
2. If this not the case and the cable connections are correct, then
the stepper motor driver in the EKD 316 might be damaged.
Remember to set o18 back to 0 after checks. If checks 1) and
2) are not correct, ensure that motor cable corrections are
correct and the cable length is less than 30 meters.
If the controllers are operated by a common analogue signal as
above, the voltage supply should be separate as shown below.
Output relay contact
The contact of the alarm relay will be made when there is an alarm.
Battery back-up
A battery back-up can be connected to terminals 3 (+) and 4 (-).
It is recommended to use 24 V DC 100 mAh UPS. The voltage
should be at least 18 V and this can be achieved by using two 9 V
100 mAh batteries in series, if temporary solution is to be used.
© Danfoss | DCS (sw) | 2016.11
DKRCC.PD.RR0.B2.02 | 9
Loading...