User Guide | Stepper Valve Extension Module, Type EKE 1P
4 | BC320219567793en-000201
© Danfoss | DCS (vt) | 2020.03
Application 1
Application mode
In application 1, the EKE 1P operates as an extension module to a
CO2 pack controller, AK-PC. It is possible to configure if the EKE 1P
is used as an extension module where the stepper output controls
the high pressure, or as an extension module where the stepper
output controls the receiver pressure.
This is configurable through a software setting (parameter “Mode”)
or through a hardware configuration. As default the hardware
configuration is enabled, which means the AI4 input is used for the
configuration as follows:
AI4 open circuit or connected to 0 V (COM): high-pressure valve driver
AI4 connected to 5 V+: receiver valve driver
The IO configuration of application 1 is determined through the
configuration of the AK-PC.
Some, all or a sub-set of the inputs and outputs may be used.
See documentation of the specific AK-PC for details.
Valve configuration
In application mode 1, the valve type is configured via the AK-PC.
Only if the valve type is set to “User Defined” in the AK-PC, it is
required to access the EKE 1P parameter list for configuring the
valve specific parameters like number of steps, max current etc.
In application mode 1, the EKE 1P will set the valve opening
degree to a fixed value in case of losing the CANBUS
communication to the AK-PC. As default the valve will close in this
case.
Application 2
Valve configuration
The valve type can be selected from an extensive list of Danfoss
standard valve types. When a standard type is selected, only a
few parameters need to be set i.e. a valve neutral zone, the valve
overdrive and valve opening degree in special situations.
If Danfoss standard valve type is not selected, app. 20 parameters
for the valve and valve motor control become visible (“Valve motor
type”, “Valve drive current” etc.). See “Menu” for details.
Analogue input scaling
The EKE 1P may be configured for various voltage ranges, e.g.
2 – 10 V. Here the valve will be 0% open at 0 V and 100% open at
10 V and proportionally opened in values between. Typical input
ranges may be configured or the voltage range may be freely
configured within 0 – 10 V and 10 – 0 V.
Note: if the minimum is set to 0 V, the valve will start opening at
0.1 V to ensure detection of a valve closure signal (0 V).
Valve neutral Zone
The EKE 1P controller has a complex algorithm implemented to
handle oscillation issues related to output valve OD by defining
some neutral zone. In neutral zone, the valve will not move until it
overcomes the definite variation in the valve opening degree.
Valve Overdrive
To compensate for lost steps, the valve may be overdriven when it
closes to 0%. i.e. it will close with extra steps to make sure that it is
fully closed. This may, however, lead to increased wear on the valve
if it occurs frequently. To prevent this, the overdrive will only be
enabled when the valve opening degree exceeds a set value and
the overdrive function may only re-occur within a set interval.
