Controlling an Electronic Expansion Valve (Stepper-type) using the AKO-16526 Controller

Introduction

The AKO-16526 controller is designed to manage a PWM-type electronic expansion valve directly. For Stepper-type valves, an external driver is required. The controller communicates with the driver to set the appropriate opening for the Electronic Expansion Valve (EEV) based on the evaporator outlet's pressure and temperature. This ensures the desired superheating value, as defined in parameter Sh, is maintained, thereby increasing the evaporator's efficiency.

Wiring Diagram

The wiring diagram illustrates the connection of the AKO-16526 controller to an EEV driver and an electronic expansion valve. It shows connections for sensors (superheating, low pressure, evaporator, cold room, suction pressure), analog inputs/outputs, auxiliary relays (AUX 1, 2, 3), fan control, and defrost functions. Power is supplied via a 100-240V~ 50/60Hz input. The diagram also depicts the main refrigeration components: compressor, condenser, liquid container, and evaporator, along with a liquid solenoid and fan.

Key connections and components shown:

• Controller Terminals: RS485, Analog In, Analog Out, various sensor inputs (S1, S2, S3, S4, S5, S6), and output terminals (AUX 1, AUX 2, AUX 3, FAN, DEF, COOL).
• EEV Driver: Receives control signals (e.g., 4-20 mA / 0-10 V) and drives the EEV.
• Sensors: Superheating sensor, Low pressure sensor, Evaporator sensor, Cold room sensor, Suction pressure sensor.
• Refrigeration System Components: Compressor, Condenser, Liquid Container, Evaporator, Liquid Solenoid, Fan.
• Power Input: 100 - 240V~ 50/60 Hz.
• Load Outputs: Compressor (3000W, 230V~), Defrost Resistors/Resistance of Cartridge (150W, 230V~), Evaporator Fans (12A, 230V~).

The function of the D2/S4 input depends on the configuration of parameter I20. The function of the AUX 2 relay depends on the configuration of parameter o10.

For further information, please refer to the user manual available on our website: https://help.ako.com/assets/uploads/351652602.pdf

Configuration

Before proceeding with the initial configuration, it is advisable to note down certain installation details:

Defrost

Note the defrosting method used: Electrical (resistors), air (evaporator fans), hot gas valve (condensing unit) or cycle reversal.

Analogue Outputs

The analogue output (ANALOG OUT) enables communication between the controller and the external controller of the electronic expansion valve and can be configured as 4-20 mA output (o30=0) or as 0-10 V output (o30=1). Consult the specifications of the external controller and note them down.

SET POINT (temperature)

Make a note of the desired set temperature value.

Type of Gas

Note the type of gas used in the installation.

Pressure Sensor Type

Note the type of evaporator pressure sensor installed: 4-20 mA (I61=1), 0-5 V (I61=2), 0.5-4.5 V (I61=3), 0-10 V (I61=4), 1-5 V(I61=5). Note also the maximum and minimum values of the pressure sensor as well as the units of pressure used (bar or Psi).

Superheating SET POINT

Enter the desired optimum superheating value.

Assistant Mode

The first time the unit receives power, it enters ASSISTANT mode. The display shows 'ini' flashing at 0. The [Up Arrow] and [Down Arrow] buttons change the value; the [Set Button] accepts the value and proceeds to the next step.

Step 1: Installation Type Selection

Select the most suitable 'InI' option based on the installation type and press [Set Button]. The available options are shown in the table below:

Note: If u00=2: o20=3, I30=0, I31=0. If u00≠2: o20=0, I30=9.

? If options 2, 5 or 7 are chosen, check the configuration of parameter I11 according to the pressure switch type used.

Configuration Steps

Step 2: Electronic Expansion Valve Type

Set this parameter to use the stepper-type electronic expansion valve: u00=2 Electronic expansion valve.

Step 3: Refrigerant Gas Type

Define the type of refrigerant gas used. Options include R404A (u02=0), R134A (u02=1), R407A (u02=2), R407F (u02=3), R410A (u02=4), R450A (u02=5), R513A (u02=6), R744 (u02=7), R449A (u02=8), R290 (u02=9), R32 (u02=10), R448A (u02=11), R1234ze (u02=12), R23 (u02=13), R717 (u02=14), R407C (u02=15), 1234yf (u02=16), R22 (u02=17), R454C (u02=18), R455A (u02=19), R507A (u02=20), R515B (u02=21), R452A (u02=22), R452B (u02=23), R454A (u02=24).

Step 4: Pressure Units

Define the pressure units to be used: I60=0 Bar, I60=1 Psi.

Step 5: Pressure Sensor Type

Define the type of pressure sensor used: I61=0 Deactivated, I61=1 4-20 mA, I61=2 0-5 V, I61=3 0.5-4.5 V, I61=4 0-10 V, I61=5 1-5 V.

Step 6: Minimum Pressure Value

Define the minimum value of the pressure sensor (I62) (value at 4 mA, 0 V, 0.5 V or 1 V according to I61).

Step 7: Maximum Pressure Value

Define the maximum value of the pressure sensor (I63) (value at 20 mA, 5 V, 4.5 V or 10 V according to I61).

Step 8: Analogue Output Type

Define the type of analogue output, which is connected to the driver input of the electronic expansion valve. Consult the external driver specifications to configure this correctly: o30=0 4-20 mA, o30=1 0-10 V.

Step 9: Temperature Set Point

Select the temperature set point.

Step 10: Superheating Set Point

Select the superheating set point.

Step 11: Default Parameters

Set all other parameters to default? dFP=0 No, the other parameters do not need to be changed. dFP=1 Yes, set all other parameters to their default values.

This option only appears if this is not the first time the set-up wizard has been run. The initial configuration is now complete, and the device will start to regulate the temperature.

Reactivating the Configuration Wizard

? The configuration wizard will not reactivate automatically. To reactivate it, activate the stand-by mode (by pressing the [Power Button] for 3 seconds), wait until the unit completely halts regulation (the [Power Indicator] will light up permanently), and press the [Up Arrow], [Down Arrow], [Set Button] buttons in this order, in sequence, not at the same time.