Compressor Feed Forward Function - Danfoss EKE 1A User Manual

Superheat controller, Type EKE 1A, 1B, 1C, 1D
Parameter Function
O010 Ext ref. supply
I034 Ext ref voltage low
I035 Ext ref. voltage high
I036 Ext ref. current low
I037 Ext ref. current high
X010 Bus ext. ref
 WARNING:
• SH reference is not allowed to offset the signal below SH min.
• Only analog input AI4 can be set as an analog external reference for displacing references
• EKE1D receives reference parameter via wired CANBus, while EKE 1C, EKE 1B receive it via Modbus.

6.2.4 Compressor feed Forward function

When a compressor speed changes, system dynamics change correspondingly. Hence, Compressor speed feed
forward function changes the PI parameter values according to the actual compressor speed, which means the
reactivity of the controller is changed.
For example, when the speed of the compressor is low, this feature increases the integration time which leads to a
slower response of the PI controller.
To use this feature bus communication is needed and the master controller must send a feed-back about the
compressor speed to the EKE controller.
EKE 1A
Applicable
 WARNING:
This function is basically used in one-to-one systems and requires a Modbus (Or CANBus in EKE 1D) to feed the
compressor speed. This functionality may not be used in multi-evaporator system.
Figure 71: compressor feedforward function
Compressor speed signal via MODbus
Master
control
EEV
© Danfoss | Climate Solutions | 2022.06
1B 1C 1D
TT
S2
Description
Define how the external reference signal is used
1 = V->SH: Displacement of SH reference given by External voltage signal.
2 = V->Max OD: Maximum opening degree of the valve given by external voltage
signal
3 = V->Temp: Displacement of temperature given External voltage signal.
4 = Bus -> SH: Displacement of SH reference given via Modbus.
5 = Bus->Max OD: Maximum opening degree of the valve given via Modbus.
6 = Bus -> T: Displacement of temperature given via Modbus
7 = mA->SH: Displacement of SH reference given by External current signal.
8= Bus->Max OD: Maximum opening degree of the valve given by External cur-
rent signal.
9 = mA->Temp: Displacement of temperature given External current signal.
Define min. reference Voltage
Define max. reference Voltage
Define min. reference current
Define max. reference current
Readout offset in Kelvin
P
BC398828796060en-000101 | 49