Danfoss EKE 1A User Manual page 60

Superheat controller and stepper valve driver, Type EKE 1A, 1B, 1C, 1D
Parameter Function
I077 Holding Current
I064 Valve step Mode
I065 Valve duty cycle
I070 Start Backlash
I071 Start backslash
I072 Overdrive
I076 Valve Excitation Time After Stop
Table 59: Common Valve parameters (For Danfoss/Non-Danfoss valves)
Parameter
I069
I073
I074
I078
I068
I079
I080
 NOTE:
Failsafe Position: During failsafe mode of operation (e.g., SH control sensor error or Thermostat sensor error) the
valve position can be set to full close, xed opening degree or average calculated OD. For detail check section
Failsafe operation and parameter list under section control advance sub section Diagnostic SH and Emergency
cooling.
© Danfoss | Climate Solutions | 2024.08
Description
For some valves, this represents the percent of the programmed Max Phase Current that
should be applied to each phase of the stepper motor to maintain the valve at its last pro-
grammed position. Not all valve designs require a holding current, make sure to check this
with your valve manufacturer
Stepper motor can be driven with various step excitation method, which depends valve re-
quirements as well as operating conditions of an application.
The user can choose
• Full stepping 1/1
• Half stepping 1/2
• Micro-stepping (1/4, 1/8, 1/16)
 NOTE:
For half and micro stepping, the risk of step loss is higher because the torque provided is low-
er
Danfoss recommends using 1/8 stepping mode as this provides a good balance between tor-
que, speed, and smooth operation.
De nes the valve motion and stop time in a window of 60 seconds.
The parameter de nes the operation of the start backlash function. The valve will normally
open from this point onwards.
The number of steps needed to correct for mechanical hysteresis when a reduction gear is
part of the valve design.
The extra steps taken to secure the closure of the valve.it is de ned as a percentage of the full
opening.
The time that the drive current is applied after the motor has stopped before going to hold-
ing current. This will make sure that the valve has achieved the nal position before going to
holding current.
Function
Valve OD During Stop
Overdrive Enable OD
Overdrive Block time
Preset OD
Valve neutral Zone
Forced overdrive
Forced overdrive time is a timer for
forced overdrive when activated to ON
Description
For some application, it is required that the valve remains open after the control-
ler is o . This parameter de nes that OD in %.
 NOTE:
This parameter requires connecting a Battery Backup
The Overdrive happens only after Exceeding Override Enable OD.
To limit how frequent overdrive can performed the parameter [I074 - Overdrive
block time] de nes the minimum time between 2 overdrive actions. The default
value is 10 minutes
Actual opening degree
1073
Override
Enabled OD
No overdrive
No overdrive
Overdrive
Overdrive 1074 - Override Block Time
The DI can be used to force the valve to go to this opening degree.
EKE controller has a complex algorithm implemented to handle oscillation issues
related to output valve OD by de ning some neutral zone. In neutral zone, the
valve will not move until it overcomes the de nite variation in the valve opening
degree.
The bene t of using such techniques will not a ect the performance of the sys-
tem but will reduce the problem related with the uctuating signal, step loss and
hysteresis in the valve.
Forced overdrive is use to trigger an overdrive purely based on time. The control-
ler will move the valve to 0 position with overdrive and immediately come back
to the requested position as per the new valve OD requirement.
Opening
Degree
(OD)
Valve position back as per
AI signal
If forced overdrive time is fulfilled
then execute overdrive
Forced overdrive time
Time
Overdrive
Overdrive
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