Danfoss EKC 315A Controller
Instructions
This document provides instructions and operational details for the Danfoss EKC 315A controller, designed for refrigeration and air conditioning applications.
Identification and Dimensions
The EKC 315A unit is identified by model numbers such as 084B7086. Dimensions are provided for reference, showing the physical size of the unit.
A system schematic illustrates the EKC 315A controller connected to sensors (S2 for evaporator outlet, S3 for air temperature) and an actuator (AKV/TQ), along with a solenoid valve.
Connections
The controller features various terminals for necessary and application-dependent connections.
Necessary Connections
- Terminals 25-26: Supply voltage 24 V a.c.
- Terminals 17-18: Signal from TQ actuator (only).
- Terminals 20-21: Pt 1000 sensor at evaporator outlet (S2).
- Terminals 14-15: Pressure transmitter (e.g., AKS 33).
- Terminals 9-10: Relay switch for solenoid valve start/stop.
- Terminals 1-2: Switch function for regulation start/stop. If no switch is connected, terminals 1 and 2 must be short-circuited.
Application Dependent Connections
- Terminals 21-22: Pt 1000 sensor for air temperature measurement (S3).
- Terminals 12-13: Alarm relay. A connection exists between 12 and 13 during alarm situations or when the controller is powered off.
- Terminals 18-19: Current signal from other regulation (Ext.Ref.).
- Terminals 23-24: Supply voltage to actuator AKV/TQ.
- Terminals 2-5: Current output for displaying superheat or air temperature, or for signaling a slave module, or for controlling an ICM valve.
- Terminals 3-4: Data communication. This connection is only used if a data communication module is installed. Proper installation of the data communication cable is crucial. Refer to separate literature RC8AC for details.
Wiring diagrams are provided for ICAD units and AKV actuators, illustrating typical connections. A graph shows the recommended cable cross-section (mm²) versus cable length (m) for a 24V supply, indicating that longer cable runs require thicker wires (e.g., 0.75 mm² for <25m, 1.5 mm² for 25-75m, 2.5 mm² for >75m).
Operation and Controls
The display shows values with three digits and can be set to display temperature in °C or °F.
Front panel LEDs indicate the status of the controller:
- The upper LED shows the valve's opening degree (short pulse for low liquid flow, long pulse for high liquid flow).
- The next LED indicates when the controller is calling for refrigeration.
- The three lower LEDs flash if there is an error. Error codes can be viewed on the display, and alarms can be canceled by briefly pressing the upper button.
The two buttons on the unit are used for navigation and adjusting settings. Pressing the upper button for a few seconds accesses the menu. Once in the menu, parameters can be selected and values changed by pressing the buttons. Pressing both buttons simultaneously saves the changes.
Examples of Operation:
- Setting Set-point: Press both buttons, use one button to select the value, then press both buttons again to confirm.
- Setting Other Menus: Press the upper button to cycle through parameters, use one button to find the desired parameter, press both buttons to view its value, use one button to change the value, and press both buttons to save.
Factory settings can be restored by disconnecting power, holding both buttons, and reconnecting power.
Menu Overview and Parameters
The controller offers a comprehensive menu for configuration and monitoring. Key parameters include:
| Function | Parameter | Min. | Max. | Factory Setting |
|---|---|---|---|---|
| Normal display | Define view in o17 | - | - | - |
| Reference | Set the required set point | -60°C | 50°C | 10 |
| Differential | r01 | 0.1 K | 20.0 K | 2.0 |
| Units (0=°C+bar / 1=°F+psig) | r05 | 0 | 1 | 0 |
| External contribution to the reference | r06 | -50 K | 50 K | 0 |
| Correction of signal from S2 | r09 | -50.0 K | 50.0 K | 0.0 |
| Correction of signal from S3 | r10 | -50.0 K | 50.0 K | 0.0 |
| Start/stop of refrigeration | r12 | OFF | On | 1 |
| Define thermostat function (0=no, 1=On/off) | r14 | 0 | 1 | 0 |
| Alarm: Upper deviation | A01 | 3.0 K | 20 K | 5.0 |
| Alarm: Lower deviation | A02 | 1 K | 10 K | 3.0 |
| Alarm's time delay | A03 | 0 min. | 90 min. | 30 |
| Regulating parameters: P: Amplification factor Kp | n04 | 0.5 | 20 | 3.0 |
| I: Integration time Tn | n05 | 30 s | 600 s | 120 |
| D: Differentiation time Td (0=off) | n06 | 0 s | 90 s | 0 |
| Max. value of superheat reference | n09 | 2 K | 50 K | 6 |
| Min. value of superheat reference | n10 | 1 K | 12 K | 4 |
| MOP (max.=off) | n11 | 0.0 bar | 60 bar | 60 |
| Period time (AKV/A valve only) | n13 | 3 s | 10 s | 6 |
| Stability factor for superheat control | n18 | 0 | 10 | 5 |
| Damping of amplification around reference | n19 | 0.2 | 1.0 | 0.3 |
| Amplification factor for superheat | n20 | 0.0 | 10.0 | 0.4 |
| Definition of superheat control (1=MSS, 2=LOADAP) | n21 | 1 | 2 | 1 |
| Value of min. superheat reference for loads <10% | n22 | 1 | 15 | 2 |
| Standby temp. (valve closed, TQ only) | n26 | 0 K | 20 K | 0 |
| Standby temp. (valve open, TQ only) | n27 | -15 K | 70 K | 20 |
| Max. opening degree | n32 | 0 | 100 | 100 |
| Min. opening degree | n33 | 0 | 100 | 0 |
| Miscellaneous: Controller's address | o03* | 0 | 119 | - |
| ON/OFF switch (service-pin message) | o04* | - | - | - |
| Define valve and output signal (0:Off, 1:TQ AO 0-20mA, 2:TQ AO 4-20mA, 3:AKV AO 0-20mA, 4:AKV AO 4-20mA, 5:AKV AO EKC 347-SLAVE, 6:ICM AO 0-20mA/ICM OD%, 7:ICM AO 4-20mA/ICM OD%) | o09 | 0 | 7 | 0 |
| Define input signal on analog input AIA (0:no signal, 1:Temp setpoint 0-20mA, 2:Temp setpoint 4-20mA, 3:Superheat ref. displacement 0-20mA, 4:Superheat ref. displacement 4-20mA) | o10 | 0 | 4 | 0 |
| Set supply voltage frequency | o12 | 50 Hz | 60 Hz | 0 |
| Select display for "normal picture" (o17) | o17 | 1 | 3 | 1 |
| Manual control of outputs (OFF: no manual control, 1: Relay ON, 2: AKV/A output ON, 3: Alarm relay activated) | o18 | off | 3 | Off |
| Working range for pressure transmitter - min. value | o20 | -1 bar | 60 bar | -1.0 |
| Working range for pressure transmitter - max. value | o21 | -1 bar | 60 bar | 12 |
| Set temp. value or opening degree for min. output signal (0 or 4 mA) (for 009 function, AKV/TQ only) | o27 | -70°C | 160°C | -35 |
| Set temp. value or opening degree for max. output signal (20 mA) (for 009 function, AKV/TQ only) | o28 | -70°C | 160°C | 15 |
| Refrigerant setting (1=R12, 2=R22, ..., 35=R438A) | o30 | 0 | 35 | 0 |
Start-up and Troubleshooting
Start-up Procedure:
- Ensure the external ON/OFF switch is off.
- Follow the menu overview to set parameters.
- Turn on the external switch to start regulation.
- Monitor room temperature or superheat on the display. A current signal representing the display can be output on terminals 2 and 5 for data logging.
If Superheat Fluctuates:
If the system is stable, factory settings usually provide good regulation. Fluctuations may indicate superheat parameters are too low. Adjust n09, n10, n18 (adaptive superheat) or n09, n10, n22 (load-defined superheat). Alternatively, regulation parameters might not be optimal.
- If oscillation time (Tp) > integration time (Tn): Increase Tn by 20%, wait for stability, or reduce Kp by 20% if oscillation persists.
- If oscillation time (Tp) < integration time (Tn): Reduce Kp by 20%, wait for stability, or repeat if oscillation persists.
Excessive Underswing at Start-up:
- For AKV valves: Adjust n22 slightly up and/or n04 slightly down.
- For TQ valves: Adjust n26 slightly down.
Controller Messages:
- E1: Fault in controller.
- E11: Valve actuator temperature out of range.
- E15: S2 sensor cut-out.
- E16: S2 sensor short-circuited.
- E17: Error message.
- E18: S3 sensor cut-out.
- E19: S3 sensor short-circuited.
- E20: Input signal on terminals 18-19 out of range.
- A1: High-temperature alarm.
- A2: Low-temperature alarm.
- A11: No refrigerant selected.
- Input signal on terminals 14-15 (PO signal) out of range.
