Introduction
The AK-CC 550B is a versatile controller designed for complete refrigeration appliance control, adaptable to various types of refrigeration appliances and cold storage rooms. It offers energy optimization, integrated display, quick setup, data communication, and a built-in clock function with power reserve.
Application
Provides complete refrigeration appliance control with flexibility for diverse applications.
Advantages
- Energy optimization of the entire refrigeration appliance.
- Single controller for multiple refrigeration appliances.
- Integrated front-mounted display.
- Quick setup with predefined settings.
- Built-in data communication capabilities.
- Built-in clock function with power reserve.
Principle of Operation
Temperature is registered by one or two sensors (S3, S4) located in the airflow before or after the evaporator. Settings for thermostat, alarm thermostat, and display reading determine sensor influence. An optional product sensor (S6) can monitor temperature at specific product locations. An evaporator sensor (S5) is used for defrosting. The controller manages the outlet to the electronic injection valve (AKV) and has 5 relay outputs configurable for various uses.
Key Functions
- Day/night thermostat with ON/OFF or modulating control.
- Product sensor (S6) with separate alarm limits.
- Switch between thermostat settings via digital input.
- Adaptive control of superheat.
- Adaptive defrosting based on evaporator performance.
- Defrost initiation via schedule, digital input, or network.
- Natural, electric, or hot gas defrost methods.
- Defrost termination by time and/or temperature.
- Coordination of defrosting among multiple controllers.
- Fan pulsing when thermostat is satisfied.
- Case cleaning function for HACCP documentation.
- Rail heat control based on day/night load or dew point.
- Door function control.
- Control of two compressors.
- Control of night blinds.
- Light control.
- Heat thermostat.
- Factory calibration for high accuracy (Pt 1000 sensor).
- Integrated MODBUS communication with optional LonWorks/DANBUSS card.
Appliance Examples
The document includes visual representations of appliance examples, showcasing the controller's integration into various refrigeration units. These examples illustrate different configurations and applications.
Operation Details
Liquid Injection
Controlled by an electronic injection valve (AKV), which acts as both expansion and solenoid valve. The controller signals the valve to open/close. An adaptive algorithm optimizes evaporator performance for constant, optimal refrigeration. Superheat is measured via pressure sensor (P0) and temperature sensor (S2) for robust and precise control. Two superheat settings are available: Dry expansion (normal) and Flooded evaporator (requires an on/off signal from a tank level switch).
Temperature Control
Temperature is monitored by sensors S3 and S4. Control can be ON/OFF with a differential or modulating. Modulating control is suitable for central plants, while ON/OFF is recommended for decentralized plants. Alarm monitoring also uses S3/S4 with adjustable weighting, minimum/maximum limits, and time delays.
Thermostat Bands
Allows for different temperature conditions for various stored products. Switching between two thermostat bands is possible via a digital input, with separate alarm limits and time delays for each band, including the product sensor.
Night Setback
Adjusts the thermostat reference value for periods of lower load, such as overnight, to save energy. Changeover can occur via an external switch signal or data communication.
Product Sensor (S6)
An optional sensor (S6) can monitor temperature at the warmest point in the appliance. It has separate alarm limits and time delays. This function is not available in Application 9.
Appliance Cleaning
A function to facilitate appliance cleaning according to standard procedures. Activated via a signal (e.g., a key switch). It involves three phases: refrigeration stop with fans running (defrost), fans stopped for cleaning, and refrigeration restart. A cleaning alarm is transmitted for documentation.
Appliance Shut-down
Closes the AKV valve and switches off all outputs, stopping the cooling appliance without triggering a "Standby alarm-A45". Can be enabled via a DI input or data communication.
Defrost Functions
The controller supports multiple defrost methods:
- Natural: Fans operate during defrost.
- Electric: Heating element is activated.
- Hot Gas: Solenoid valves control hot gas flow through the evaporator.
The defrost sequence includes pump down, defrosting, waiting, draining (hot gas only), drip off, and fan delay.
Hot Gas Defrost
Suitable for small systems. Relay 2 controls the suction valve, and Relay 4's changeover function can manage bypass and/or hot gas valves. Drip tray heating can also be controlled.
Defrost Start Methods
- Interval: Fixed time intervals.
- Refrigeration Time: Based on accumulated refrigeration time.
- Schedule: Fixed times of day (up to 6 times).
- Contact: Via a digital input signal.
- Network: Via data communication.
- Adaptive: Based on intelligent registration of evaporator performance.
- Manual: Activated from the controller button or via parameter.
Defrost Stop Methods
- Time-based.
- Temperature-based (with time as a safety backup).
Coordinated Defrost
Can be arranged via wire connections (DI2) or data communication managed by a system unit. This ensures that multiple controllers defrost in sequence or in groups to maintain overall cooling.
Adaptive Defrosting
Assesses the need for defrosting based on airflow and evaporator performance. Options include monitoring, day/night adaptive defrosting, or full adaptive defrosting that can initiate extra defrosts as needed. Requires specific sensor inputs (AKV, S3, S4, Pc).
Melting Function
Prevents evaporator blockage by frost during long periods of operation within a specific temperature range (-5°C to +10°C). Refrigeration is stopped for a set melting period to melt frost.
Real-time Clock
A built-in clock with a 4-hour power reserve, used for scheduling defrosts. Can be updated via data communication.
Control of Two Compressors
When Application 5 is selected, the controller can manage two compressors of the same size. It alternates compressor usage to balance operating times and ensures one compressor can handle the load if needed. Settings for minimum ON/OFF times are prioritized.
Rail Heat Control
Allows for energy-saving pulse control of rail heat. This can be based on day/night load (setting ON periods as a percentage of time) or dew point (requiring a system manager to provide dew point data). Rail heat is active during defrosting as configured.
Fan Control
Fans can be pulse-controlled for energy savings during the thermostat's cutout period or during night operation. A period time and ON percentage are set. Fans can also be stopped if the temperature at sensor S5 exceeds a set limit during plant breakdowns to prevent rapid temperature rise.
Light Function
Controls lighting in refrigeration appliances or cold rooms. It can be triggered by a door contact (with a 2-minute delay after closing), day/night function, or data communication. The light load is connected to the NC switch on the relay, ensuring light remains on if controller power fails.
Night Blind Control
Motorized night blinds can be controlled automatically, typically following the light function (open when light is on, closed when light is off). A digital input allows for forced opening to facilitate product filling. The fan stops for 2 minutes when the night blind rolls down.
Digital Inputs (DI1, DI2, DI3)
The controller features two digital inputs (DI1, DI2) with contact function and one (DI3) with a high-voltage signal. These can be configured for various functions, including:
- Door contact function (with alarm or refrigeration stop).
- Defrost start.
- Main switch (start/stop cooling).
- Night setback.
- Thermostat band switch.
- General alarm monitoring.
- Case cleaning.
- Appliance shutdown.
- Forced cooling.
- Override of night blinds.
- Allow flooded evaporator.
- Coordinated defrost (DI2 only).
- Forced closing of valve (DI3 only).
- Refrigerant leak alarm (DI1 and DI2 only).
Forced Closing
AKV valves can be closed via an external signal, used with the compressor's safety circuit to prevent liquid injection when the compressor stops. This function can be configured via DI3 or data communication.
Door Contact Function
Monitors door status. If opened for longer than a set delay, an alarm is triggered. In another mode, opening the door stops refrigeration, turns on the light, and resumes refrigeration after a restart time if the door remains open.
Heating Function (Application 8)
Used to prevent temperatures from dropping too low, e.g., in cutting rooms. The heating cut-off limit is set relative to the refrigeration thermostat's cut-out limit to avoid simultaneous heating and cooling. A time delay can prevent heating during short-term air temperature drops.
Data Communication
The controller has built-in MODBUS data communication. An optional LonWorks / DANBUSS communication card can be mounted. Displays (EKA 163B/164B) can be connected. For distances over 15m or when using data communication, specific modules and configurations are required. Controller addresses must be set correctly for communication.
Applications Overview
The controller offers 10 distinct applications, each tailored for commercial refrigeration systems. A setting configures input/output functions for the selected application. Applications 1-4 are standard, differing in combinations of alarm, rail heat, compressor, and light functions. Applications 5-8 introduce special functions like dual compressor control, hot gas defrost, night blind control, and heat thermostat. Applications 9 and 10 handle appliances with two refrigeration sections, differing in defrost output configuration.
Application 1-4: Standard applications with variations in alarm, rail heat, compressor, and light outputs.
Application 5: Two-compressor operation with staggered start-up and runtime equalization.
Application 6: Hot gas defrosting, adapted for commercial appliances with limited system filling.
Application 7: Control of night blinds, linked to the light function, with an option for forced opening.
Application 8: Heat thermostat for precise temperature control, often used in cutting rooms.
Application 9: Two refrigeration sections with individual temperature measurement and two defrost outputs. Product sensor not available.
Application 10: Two refrigeration sections with individual temperature measurement and one defrost output.
Connections
The controller provides various connection terminals for sensors, digital inputs, outputs, and data communication. Sensors like S2, S3, S4, S5, S6 are typically Pt 1000 ohm or PTC 1000 ohm. Digital inputs (DI1, DI2, DI3) support contact or high-voltage signals for diverse functions. Outputs (DO1-DO6) control components like the AKV valve, fans, relays, and lighting. Data communication can be via RS485 (MODBUS, LON, DANBUSS) or RJ45 (TCP/IP). Supply voltage is 230 V a.c.
Sensor Types:
- S2, S6: Pt 1000 ohm.
- S3, S3B, S4, S5, S5B: Pt 1000 ohm or PTC 1000 ohm (all must be the same type).
Digital Inputs:
- DI1, DI2: Contact function, configurable for various control and alarm functions.
- DI3: High voltage input (0/230 V a.c.), configurable for control and alarm functions.
Outputs:
- DO1: AKV valve control (230 V a.c. coil).
- DO2: Alarm relay, Rail heat, Drip tray heating, Night blind, Suction line valve.
- DO3: Refrigeration, Rail heat, Heat function, Defrost 2.
- DO4: Defrost, Hot gas/drain valve.
- DO5: Fan.
- DO6: Light relay, Rail heat, Compressor 2.
Data Communication:
- RS485 (MODBUS, LON, DANBUSS) via terminals 51, 52, 53.
- RJ45 for TCP/IP (OEM specific).
- MODBUS via terminals 56, 57, 58.
Display: External displays (EKA 163B/164B) can be connected.
Power Supply: 230 V a.c. (+10/-15 %).
Technical Data
- Supply Voltage: 230 V a.c. +10/-15 %, 5 VA, 50/60 Hz.
- Sensor Types: Pt 1000 ohm or PTC 1000 ohm (S3-S5).
- Measuring Range: -60 to +120 °C.
- Controller Accuracy: ±1 K below -35 °C, ±0.5 K between -35 to +25 °C, ±1 K above +25 °C.
- Pressure Transmitter: AKS 32R.
- Display: LED, 3-digit. External EKA 163B/164B.
- Digital Inputs: DI1, DI2 (contact), DI3 (230 V a.c.). Max cable length 15m for DI1/DI2.
- Outputs: Solid state (DO1), Relays (DO2-DO6).
- Environment: Operating: 0 to +55 °C; Transport: -40 to +70 °C. Humidity: 20-80% Rh (non-condensed).
- Enclosure: IP 20.
- Mounting: DIN-rail or wall.
- Weight: 0.4 Kg.
- Power Reserve (Clock): 4 hours.
- Approvals: CE (Low Voltage Directive, EMC).
Ordering Information
The AK-CC 550B controller and related accessories like communication modules and external displays are available via specific order codes. Examples include:
- AK-CC 550B Controller with MODBUS: Code no. 084B8032
- Data communication module LON RS 485: Code no. 084B8579
- External display EKA 163B: Code no. 084B8574
Detailed ordering information for various modules and displays is provided in the manual.
Parameter Survey
The controller offers extensive parameterization for fine-tuning its operation. Below is a summary of key parameter groups and examples. For a complete list, refer to the detailed menu survey.
Thermostat Parameters
| Function | Parameter Code | Min Value | Max Value | Factory Setting | Description |
|---|---|---|---|---|---|
| Setpoint | (Displayed value) | - | - | (Varies) | Current target temperature. |
| Differential | r01 | 0.1 K | 50 K | 2 K | Temperature difference for compressor cycling. |
| Max. Setpoint Limit | r02 | -49 °C | 50 °C | 50 °C | Upper limit for adjustable setpoint. |
| Min. Setpoint Limit | r03 | -50 °C | 10 °C | -50 °C | Lower limit for adjustable setpoint. |
| Display Adjustment | r04 | -10 K | 10 K | 0 K | Offset for temperature display. |
| Temperature Unit | r05 | 0 (°C) | 1 (°F) | 0 (°C) | Selects temperature unit. |
| Night Offset | r13 | -50 K | 50 K | 0 K | Temperature adjustment for night operation. |
| Thermostat Mode | r14 | 1 (ON/OFF) | 2 (Modulating) | 1 | Selects thermostat control type. |
| Thermostat S4% | r15 | 0 % | 100 % | 100 % | Weighting of S4 sensor for thermostat control. |
Alarm Parameters
| Function | Parameter Code | Min Value | Max Value | Factory Setting | Description |
|---|---|---|---|---|---|
| Alarm Delay (Air Temp) | A03 | 0 min. | 240 min. | 30 min. | Time delay for air temperature alarms. |
| Door Open Delay | A04 | 0 min. | 240 min. | 60 min. | Time delay for door open alarm. |
| High Limit Air Temp | A13 | -50 °C | 50 °C | 8 °C | Upper limit for high temperature alarm. |
| Low Limit Air Temp | A14 | -50 °C | 50 °C | -30 °C | Lower limit for low temperature alarm. |
| S6 Alarm Time Delay | A26 | 0 min. | 240 min. | 30 min. | Time delay for product sensor (S6) alarms. |
| Alarm S4% | A36 | 0 % | 100 % | 0 % | Weighting of S4 sensor for alarm thermostat. |
Defrost Parameters
| Function | Parameter Code | Min Value | Max Value | Factory Setting | Description |
|---|---|---|---|---|---|
| Defrost Method | d01 | 0 (Off) | 2 (Gas) | 0 (Off) | Selects defrost method: Electric, Gas, or Off. |
| Defrost Stop Temperature | d02 | 0 °C | 50 °C | 6 °C | Temperature at which defrost stops. |
| Defrost Interval | d03 | 0 hrs (Off) | 240 hrs | 8 hrs | Time interval between automatic defrost starts. |
| Max Defrost Duration | d04 | 0 min. | 360 min. | 45 min. | Safety time limit for defrost duration. |
| Adaptive Defrost Mode | d21 | 0 (Off) | 4 (Full adaptive) | 0 (Off) | Configures adaptive defrosting behavior. |
Fan Parameters
| Function | Parameter Code | Min Value | Max Value | Factory Setting | Description |
|---|---|---|---|---|---|
| Fan Stop Temperature | F04 | -50 °C | 50 °C | 50 °C | Temperature at which fans stop (error condition). |
| Fan Pulse Mode | F05 | 0 (No pulse) | 2 (Night operation only) | 0 (No pulse) | Enables pulse operation for fans. |
| Fan ON % | F07 | 0 % | 100 % | 100 % | Percentage of cycle time fans are ON. |
Miscellaneous Parameters
| Function | Parameter Code | Min Value | Max Value | Factory Setting | Description |
|---|---|---|---|---|---|
| DI1 Configuration | o02 | 0 (Not used) | 21 (Flooded evaporator) | 0 (Not used) | Configures function for Digital Input 1. |
| Network Address | o03 | 0 | 240 | 0 | Address for data communication. |
| Access Code 1 | o05 | 0 | 100 | 0 | Access code for all settings. |
| Sensor Configuration | o06 | 0 (Pt1000) | 1 (PTC1000) | 0 (Pt1000) | Selects sensor type (Pt1000 or PTC1000). |
| DI2 Configuration | o37 | 0 (Not used) | 21 (Flooded evaporator) | 0 (Not used) | Configures function for Digital Input 2. |
| Application Mode | o61 | 1 | 10 | 1 | Selects the operating application (1-10). |
| DI3 Configuration | o84 | 0 (Not used) | 21 (Flooded evaporator) | 0 (Not used) | Configures function for Digital Input 3 (high voltage). |
Operation and Setup
The controller displays values with three digits and can be set to °C or °F. A quick start procedure involves stopping regulation (r12=0), selecting electrical connection, setting the application mode (o61), choosing a preset setting (o62), and selecting the refrigerant (o30). Regulation is then started (r12=1). Network setup involves setting the address (o03).
Button Functions: Upper and lower buttons adjust values. Pushing the upper button for a few seconds accesses parameter codes. Middle buttons navigate and confirm changes. A short press of the upper button displays alarm codes. A short press of the lower button reads sensor data (e.g., defrost sensor). Pushing the lower button for four seconds manually starts or stops a defrost.
Alarm Handling: LEDs flash during an alarm. Pushing the top button displays the error code. Alarms can be acknowledged by briefly pushing the top button.
Quick-Setup Presets
The controller offers preset configurations for different cases (e.g., Case, Room) to simplify setup. These presets adjust parameters like temperature setpoints, defrost settings, and sensor configurations.
| Case | Preset Setting (o62) | Temperature (SP) | Max. Temp. Setting (r02) | Min. Temp. Setting (r03) | Sensor Signal for Thermostat S4% (r15) | Defrost Stop on Time | Defrost Stop on S5 | DI1 Config. (o02) |
|---|---|---|---|---|---|---|---|---|
| Case | 1 | 2 °C | 6 °C | -4 °C | 100% | 6 h | 0 | 10 (Case cleaning) |
| Room | 2 | 4 °C | 10 °C | 0 °C | 100% | 8 h | 1 | 2 (Door function) |
| Room | 3 | -28 °C | -22 °C | -30 °C | 100% | 12 h | 1 | 2 (Door function) |
Fault Messages
In case of errors, LEDs flash and the alarm relay activates. Error codes are displayed by pushing the top button. Alarms are categorized as A-alarms (appear after delay) or E-alarms (appear immediately). Common codes include:
| Code / Alarm Text | Description | Alarm Relay Groups (P41) |
|---|---|---|
| A1 / --- High t.alarm | High temperature alarm | 1 |
| A2 / --- Low t. alarm | Low temperature alarm | 2 |
| A4 / --- Door alarm | Door alarm | 8 |
| A13 / --- High temp S6 | Temperature alarm. High S6 | 1 |
| E1 / --- Ctrl. error | Faults in the controller | 32 |
| E6 / --- RTC error | Check clock | 32 |
| E25 / --- S3 error | Error on S3 sensor | 4 |
