Danfoss EKC 201C Controller for Temperature Control
- EKC 201C with double thermostat
Introduction
The Danfoss EKC 201C is a controller used for temperature control of refrigeration appliances, particularly in supermarkets. Its design with plug connections makes it primarily intended for OEMs in the refrigeration appliance industry.
Principle
The controller features a double thermostat function. Two sensors, typically placed in the cold air current after the evaporator (Sin) and in the hot air current in front of the evaporator (Sout), are used. Refrigeration is initiated only when both thermostats call for it. The controller can adapt to changed circumstances, such as when a "night lid" is placed on the appliance. It's also possible to use only the Sout thermostat for display and control, or to omit the Sin sensor entirely.
Connection
The controller utilizes plug connections for quick and easy installation, eliminating the need for screw terminals. Sensors with plug connections are available in various lengths.
Advantages
- Automatic detection of the "night lid" status.
- Integrated refrigeration-technical functions, replacing the need for multiple thermostats and timers.
- Display of temperatures, times, operating conditions, parameter codes, and alarm/error codes.
- Three LEDs indicate the system's current function: refrigeration, defrost, and fan operation. All LEDs flash during an alarm.
- Facilitates easy data communication setup at a later date.
Functions
- Double thermostat function (Sin thermostat can be optional).
- Adjustable alarm limits when the night lid is active.
- Relay outputs for: refrigeration (compressor), fan, defrost, and alarm.
- Digital inputs for coordinated defrost start, defrost retransmission, and contact position via data communication.
Diagrams (Textual Descriptions)
- Page 2: Diagram illustrating sensor placement (Sin, Sout) in relation to the evaporator and air currents. Another diagram shows the effect of a "night lid" on temperature regulation curves. A connection diagram shows typical sensor and relay terminal assignments.
- Page 3: Diagrams show temperature regulation curves with and without a "night lid", illustrating how Sin and Sout sensors influence operation. A block diagram depicts the setup for coordinated defrost using wire connections between main and secondary controllers.
- Page 15: Diagrams illustrate the effect of the night lid on temperature regulation and alarm limits, showing how Sin and Sout references are affected.
Function Details
Thermostat Operation
The controller uses two thermostats, Sin and Sout, each with its own differential. Refrigeration starts only when both thermostats call for cold temperatures. The setting principle involves setting Sin low enough to always call for refrigeration when the night lid is off, and Sout to be the primary controlling thermostat. When a night lid is applied, the Sin temperature falls and participates in regulation. If the system uses higher suction pressure at night, Sout becomes the controlling thermostat.
Coordinated Defrost
Coordinated defrost can be managed via cable connections between controllers or through data communication. In a wired setup, one controller acts as the main controller, initiating defrost for all connected secondary controllers. For data communication, an override function from a gateway coordinates defrost.
Extra Options
- An external display unit can be mounted to show controller values without providing operational buttons.
- Plug modules can be added later for expanded functionality.
- A real-time clock module allows setting up to six defrost times per day/night, with battery backup.
- A data communication module enables PC operation and monitoring.
Survey of Functions
The controller offers various functions and parameters for temperature control and defrost management. Key functions include:
| Function | Parameter | Description |
|---|---|---|
| Normal display | Displays temperature from Sin or Sout sensor (determined by setting 017). | |
| Thermostat Reference | Regulation based on set values. | |
| Temperature unit | r05 | Selects °C or °F for display. |
| Differential Sout | r07 | Defines the temperature difference for refrigeration activation based on Sout. |
| Differential Sin | r08 | Defines the temperature difference for refrigeration activation based on Sin. |
| Correction of signal from Sout | r09 | Allows compensation for long sensor cables. |
| Correction of signal from Sin | r10 | Allows compensation for long sensor cables. |
| Sin thermostat reference | r20 | Sets the temperature difference between Sin and Sout references, representing the appliance's characteristic cold loss. |
| Alarm | Controller provides alarms for various situations. LEDs flash and alarm relay activates during an alarm. | |
| Alarm delay | A03 | Sets a time delay before an alarm becomes active after a limit is exceeded. |
| Door alarm delay | A04 | Specific time delay for door alarms. |
| Upper deviation for Sout | A05 | Sets the upper limit for high temperature alarms for Sout. |
| Lower deviation for Sout | A06 | Sets the lower limit for low temperature alarms for Sout. |
| Upper deviation for Sin | A07 | Sets the upper limit for high temperature alarms for Sin. |
| Lower deviation for Sin | A08 | Sets the lower limit for low temperature alarms for Sin. |
| Displacement of Sin alarms (night lid on) | A09 | Adjusts alarm limits for Sin when the night lid is on. |
| Compressor Min. ON-time | c01 | Minimum time the compressor must run after starting. |
| Compressor Min. OFF-time | c02 | Minimum time the compressor must remain stopped. |
| Safety functions for sensor defects | Controller manages compressor operation and alarms in case of sensor failure. It also uses average ON/OFF times after 72 operations. | |
| Compressor stop at open door | c04 | Stops the compressor if a door monitoring function is enabled and the door is opened. |
| Defrost | Controller includes a timer for periodic defrost. Can be set for electric or hot gas defrost. | |
| Compressor ON during defrost | d01 | Configures whether the compressor relay should be activated during defrost. |
| Defrost stop temperature | d02 | Sets the temperature at which defrost is stopped. |
| Interval between defrost starts | d03 | Sets the frequency for defrost starts (e.g., every X hours) or can be turned off. |
| Max. defrost duration | d04 | Safety period to stop defrost if temperature-based stop is not achieved. |
| Time displacement of defrost cutins during start-up | d05 | Delays defrost starts for multiple appliances to avoid load peaks. |
| Drip-off time | d06 | Time after defrost until compressor resumes operation (evaporator dripping time). |
| Fan start delay after defrost | d07 | Time after compressor start before fan resumes operation. |
| Fan start temperature | d08 | Sets a temperature threshold for fan start, potentially earlier than the delay function. |
| Fan cut in during defrost | d09 | Determines if the fan operates during defrost. |
| Defrost sensor | d10 | Selects either Sdef or Sout as the defrost sensor. |
| Delayed temperature alarm after defrost | d11 | Suppresses high-temperature alarms immediately after defrost. |
| Delay of display view after defrost | d12 | Cancels or suppresses the display of high temperatures immediately after defrost. |
| Defrost at power up | d13 | Configures whether a defrost cycle should start after a power failure. |
Operation and Settings
The controller's operation involves setting parameters, managing alarms, and understanding its status indicators.
Display and LEDs
The display shows values with three digits, configurable for °C or °F. Front panel LEDs indicate the status of belonging relays (refrigeration, defrost, fan). If an error occurs, the LEDs flash, and error codes can be viewed and cleared via the upper button.
Buttons
Two buttons are used for adjusting values (higher/lower). Accessing the menu requires pressing the upper button for a few seconds. Parameters are selected, and values are changed by pressing buttons simultaneously. Changes are saved by pressing both buttons again.
- Upper button: Access menu / Cancel alarm.
- Lower button: Access changes.
- Both buttons simultaneously: Save change.
Examples of Operations
The manual provides examples for common operations:
- Reading temperature: Push both buttons simultaneously to view the temperature at the other sensor. Push the lower button to view the defrost sensor temperature.
- Setting a menu: Push the upper button until the parameter is shown, then push one button to find the parameter, and finally push both buttons simultaneously to display the value. Adjust the value with one button, then push both buttons to save.
- Manual defrost: Push the lower button for 20 seconds to start or stop a defrost cycle.
- Alarm handling: When an alarm occurs, LEDs flash. Pushing the upper button displays the alarm code.
Menu Survey Table
The following table summarizes the controller's functions and parameters:
| Function | Parameter | Min. | Max. | Miscellaneous |
|---|---|---|---|---|
| Normal display | °C | °C | Shows temperature at selected sensor. | |
| Thermostat | ||||
| Cutout value for Sout | -50°C | 50°C | ||
| Temperature unit | r05 | °C | °F | |
| Differential Sout | r07 | 0.1 K | 20 K | |
| Differential Sin | r08 | 0.1 K | 20 K | |
| Correction of the signal from Sout | r09 | -20.0 K | 20.0 K | |
| Correction of the signal from Sin | r10 | -20.0 K | 20.0 K | |
| Delta Sin Sout (Sin reference) | r20 | 0 | 10 K | |
| Alarm | ||||
| Delay for temperature alarm | A03 | 0 | 90 min | |
| Door alarm delay | A04 | 0 | 60 min | |
| Upper deviation for Sout | A05 | 0 K | 50 K | |
| Lower deviation for Sout | A06 | -50 K | 0 K | |
| Upper deviation for Sin | A07 | 0 K | 50 K | |
| Lower deviation for Sin | A08 | -50 K | 0 K | |
| Displacement of Sin alarms (night lid on) | A09 | -50 K | 50 K | |
| Compressor | ||||
| Min. ON-time | c01 | 0 min | 15 min | |
| Min. OFF-time | c02 | 0 min | 15 min | |
| Cutin frequency on sensor fault | c03 | 0% | 100% | |
| Compressor stop at door alarm (Yes/No) | c04 | No | Yes | |
| Defrost | ||||
| Compressor ON during defrost | d01 | No | Yes | |
| Defrost stop temperature | d02 | 0 | 25°C | |
| Interval between defrost starts | d03 | OFF | 48 hours | |
| Max. defrost duration | d04 | 0 | 180 min | |
| Time displacements for defrost cutins during start-up | d05 | 0 | 60 min | |
| Drip-off time | d06 | 0 | 20 min | |
| Delay for fan start or defrost | d07 | 0 | 20 min | |
| Fan start temperature(>25°C =OFF) | d08 | -25 | 26°C | |
| Fan cut in during defrost (yes/no) | d09 | no | yes | |
| Defrost sensor | d10 | Out | Def | Out: Sout used. Def: Sdef used. |
| Delay for temperature alarm after defrost | d11 | 0 | 200 min | |
| Delay of display view after defrost | d12 | 0 | 30 min. | |
| Defrost at power up | d13 | no | yes | |
| Realtime clock (if mounted) | t01-t06, t11-t16 | OFF | 23 hours / 59 min | Sets defrost start times. |
| Fan | ||||
| Fan stop on compressor cut out | F01 | no | yes | |
| Delay for fan stop when compressor cuts out | F02 | 0 | 15 min | |
| Fan stop at open door (yes/no) | F03 | No | Yes | |
| Miscellaneous | ||||
| Delay of output signal after start-up | 001 | 0 | 600 sec | |
| Digital input signal | 002 | OFF | 5 | OFF=not used, 1=Data communication, 2=Defrost, 3=Night cover, 4=External start/stop, 5=Coordinated defrost with wire connections, 6=Door switch. |
| Network address | 003* | 0 | 60 | Requires data communication module. |
| ON/OFF switch (service-pin message) | 004* | OFF | 100 | |
| Access code | 005 | OFF | 100 | Protects settings. |
| Used sensor type (Pt / PTC) | 006 | Pt | PTC | |
| Coordinated defrost with wire conntections | 013 | OFF | 2 | OFF= not used, 1=Main controller, 2=Secondary controller. |
| Active thermostat (active sensor) | 014 | Aut | Out | Aut: Both thermostats. Out: only Sout. |
| Display step = 0.5 (only if Pt sensor) | 015 | no | yes | no=0.1, yes=0.5. |
| Max. Hold time after coordinated defrost | 016 | 1 | 30 min | |
| Select sensor signal for the display | 017 | Aut | In | Aut: Automatic Sout/Sin changeover. Out: Always Sout. In: Always Sin. |
| Manual control of outputs | 018 | OFF | 5 | OFF=No manual control. 1-5: Select output to control. Reset to OFF after use. |
| Relay used (Alarm/light) | 036 | 1 | 2 | 1=Alarm, 2=Light. |
Fault Messages and Alarms
The controller provides fault messages and alarms to indicate operational issues.
Fault Message
In error situations, front panel LEDs flash, and the alarm relay activates. Pushing the top button displays the alarm report. Errors can be daily operation alarms or installation defects. A-alarms appear after a set delay, while E-alarms are immediate.
Alarms List
| Message | Alarm |
|---|---|
| A4: Door alarm | Door Alarm |
| A5: Information. Parameter 016 has expired | Max Hold Time |
| A6: High-temperature alarm Sout | Sout High Temp. |
| A7: Low-temperature alarm Sout | Sout Low Temp. |
| A8: High-temperature alarm Sin | Sin High Temp. |
| A9: Low-temperature alarm Sin | Sin Low Temp. |
| E1: Fault in controller | Contr Fault |
| E4: Sdef disconnected | Def Sensor Err. |
| E5: Short-circuited Sdef | Def Sensor Err. |
| E6: Error in real-time clock. Check battery/ Reset clock. | |
| E7: Sout disconnected | Sout Sensor Err. |
| E8: Short-circuited Sout | Sout Sensor Err. |
| E9: Sin disconnected | Sin Sensor Err. |
| E10: Short-circuited Sin | Sin Sensor Err. |
Operating Status Codes
Status codes provide insight into the controller's current state:
| Code | Meaning |
|---|---|
| S1 | Waiting for end of coordinated defrost. |
| S2 | Compressor operating; must run for at least x minutes. |
| S3 | Compressor stopped; must remain stopped for at least x minutes. |
| S4 | Evaporator drips off and waits for time to run out. |
| S6 | Regulation without night lid (Sout regulation). |
| S7 | Regulation with night lid (Sin regulation). |
| S10 | Refrigeration is stopped by internal or external start/stop. |
Alarm Destinations: The importance of individual alarms can be defined via settings, influencing how alarms are reported.
Data Communication
The EKC 201C can be integrated into a data communication network, allowing remote monitoring and control.
Capabilities
- Controllers connect via a plug-in module (e.g., EKA 171) to a two-core cable.
- Up to 60 controllers can be connected to one cable.
- A gateway (e.g., AKA 243) manages communication, collects data, and can trigger alarms.
- The gateway can connect to a modem for remote notification of alarms.
- PC-based system software (e.g., AKM) allows full operation and monitoring of controllers.
- Data can be uploaded daily, and functions like trend diagrams and log collection are available.
Alarms via Data Communication
When extended with data communication, the importance of transmitted alarms can be defined (0-3). This setting determines how the gateway responds to alarms, such as activating a relay output or suppressing information.
Diagrams (Textual Descriptions)
- Page 14: Diagrams illustrate a typical data communication setup involving controllers, a gateway, modem, and PC. An example menu display shows how measurements and settings are presented.
Data and Specifications
Key technical data and specifications for the EKC 201C controller:
| Attribute | Specification |
|---|---|
| Supply voltage | 12 V a.c./d.c. ±15/-15% |
| Power consumption | 2.5 VA (requires min. 3 VA transformer) |
| Sensors (3) | Pt 1000 or PTC (R25 = 1000 ohm) |
| Measuring range | -60 to +50°C |
| Controller sensor system accuracy | ±0.5°C (for sensor temperature -35 to +25°C); ±1°C (for sensor temperature -60 to -35°C and +25 to +50°C) |
| Display | LED, 3-digits |
| Digital input | Signal from contact function |
| Connecting cable | Max. 1.5 mm² multi-wire cable |
| Relays | Refr. relais: SPST NC, 6A ohmic/3A AC15 inductive. Defrost relais: SPST NC, 6A ohmic/3A AC15 inductive. Fan motor relais: SPST NO, 6A ohmic/3A AC15 inductive. |
| Common terminal | Max. 11 A in the common connection |
| Alarm relais | SPST NO, 4A ohmic/1A AC15 inductive. |
| Ambient temperature (Dur. operation) | 0-55°C |
| Ambient temperature (Dur. transport) | -40-70°C |
| Density | IP 54 |
| Approvals | EU Low Voltage Directive, EMC demands (EN 60730-1, EN 60730-2-9, EN 50082-1). |
Diagrams (Textual Descriptions)
- Page 12: Diagrams show the controller's physical dimensions and terminal layout. Product survey images display the EKC 201C, EKA 172 (Real time clock), EKA 171C (Data communication module), EKA 161 (Display unit), and associated accessories. An ordering table lists these items with their functions and code numbers.
- Page 13: Detailed connection diagrams show terminal assignments for supply voltage, digital inputs, relays, alarms, and sensors (Sin, Sdef, Sout). It also illustrates the physical plugs used and describes coordinated defrost connections via wire and data communication.
Appendix
Night Lid Operation
The controller's function can be influenced by a "night lid" status, which can be detected via a DI input or by the interaction of the Sin and Sout thermostats. This affects temperature regulation and alarm limits.
Temperature Alarms
Minimum and maximum limits are available for both Sin and Sout temperatures. These limits can be adjusted when the night lid is on or when a specific DI input signal is received.
How to Set the Controller
The manual provides a step-by-step guide for setting the controller, involving setting the Sout thermostat, adjusting the Sin reference (r20), and verifying temperatures. It emphasizes measuring the lowest Sin temperature and setting the Sin reference relative to the Sin differential and the lowest Sin temperature.
Troubleshooting
If the controller fails to start, checks should include verifying that the sensor type matches the setting (006) and confirming the controller's operating status.
Product Survey and Ordering
The EKC 201C is part of a range of refrigeration control products. Available accessories and related modules include:
| Type | Function | Code no. |
|---|---|---|
| EKC 201C | Temperature controller with coordinated defrost via wire connections | 08487068 |
| EKA 172 | Real time clock | 08487070 |
| EKA 171C | Data communication module (FTT 10 module) | 08487255 |
| EKA 171C | Data communication module (RS 485 module) | 08487256 |
| EKA 161 | Display unit | 08487019 |
| Wire for the display unit | (2 m with plug, 24 pcs.) | 08487179 |
