Product Overview

© Danfoss | DCS | 2019.04
Data sheet | Superheat controller type EKE 1A, EKE 1B, EKE 1C
DKRCC.PD.RS0.A4.02 | 7
3.1 Hardware
The number of available DI inputs diers in various model of EKE controller. This feature is especially
useful for systems where the EKE is not connected to a system controller via data communication. In
this case the digital inputs can be used to interact with the EKE.
The available digital inputs DI can be used for the following functions:
a. Injection control ON/OFF. b. Defrost sequence. c. Heating and cooling selection mode. d. Preset OD.
Injection control ON/OFF
The controller can be started and stopped externally via a contact function connected to DI input
terminals and activating the feature. Regulation is stopped when the connection is open. The
function must be used when the compressor is stopped. The controller then closes the valve so that
the evaporator is not charged with refrigerant. This can be achieved by: For EKE 1A, Use O003 DI
conguration. When O003 set to Not used. EKE 1A can be turned on by R012. When O003 is set to
Main switch, both DI1 and R012 is required to start the controller.
For EKE 1B and 1C, Use O002 DI conguration, When it’s set to “Bus->Start Stop”, the EKE requires both
R012 and Modbus signal to start. When it’s set to “Main switch”, the EKE requires both R012 and D1 to
start.
Heating and cooling selection mode
This feature is useful especially for Heat pump application where two sets of superheat settings is
required. Heat / Cool selection is possible using digital input DI function or via RS485.
The relay for the liquid line solenoid valve will operate when refrigeration is required. The relay for
the alarm function works in such a way that the contact is closed in alarm situations and when the
controller is de-energised. The digital output DO1 O013 can be congured for solenoid valve, max
capacity or for alarm function.
For safety reasons the liquid ow to the evaporator must be cut o if there is power failure for the
controller. As the Stepper valve is provided with step motor, it will remain open in power failure
situation. There are two ways of coping with this situation.
One of the following two solutions can be applied in the system:
• Mounting of a solenoid valve in front of EEV
• Mounting of a battery backup for EEV valve
The valve can be controlled manually by setting the desired opening degree via Analog signal or
communication bus used for commissioning purpose. A special service mode is also available for
service and testing purpose.
The voltage signal e.g. 0 – 10 V can be used in all EKE controllers where as current signal e.g 0 – 20 mA
signal is only available in EKE 1C.
External Reference Signal :
External Reference such as analog signal can be used either :
a. To drive the stepper motor valve to a desired opening degree
b. To displace temperature reference or superheat reference and max OD.
The controller can be provided with data communication so that it can be connected to other devices
in the systems that can be connected with a data communication. In this way operation, monitoring
and data collection can be performed from one device i.e PC – which will be benet for the diagnostic
or during the installation processes.
Reading External sensor values:
It is possible to substitute the physical sensors of the EKE controller by writing sensor values via
MODbus. These Modbus values need to be updated frequently. The frequency of update should be
according to the Modbus maximum update interval G004
Two sets of light-emitting diodes makes it possible to follow the operation status of the valve and
the controller . They indicate the following:
• Power/data transmission and Alarm/Error indication
• Stepper valve operational status
Digital inputs
3.0 Main Feature overview
Digital Output (Relay)
Handling power failure
Manual control
Analog Inputs
Communication:
RS485 RTU/ CANbus
Light-emitting diodes
(LEDs)