Danfoss EKC 202

Refrigeration controller

The EKC 202 is Danfoss's panel controller for refrigerated cabinets and cold rooms. It switches the compressor or solenoid valve, defrost, fans and an alarm or light relay from an air probe and an S5 evaporator probe. With the EKA 178A module fitted it answers Modbus RTU on RS-485, and Danfoss publishes a parameter number (PNU) for each reading: the register address is the PNU minus 1, and temperatures are signed tenths of a degree. The EKC 202A, B and C share one list. The EKC 202D adds a second air probe (S3 and S4) and a second digital input, with its own list.

Danfoss EKC 202
  • Modbus RTU

Refrigeration controller

Download EKC 202A, B and C template Ask an engineer

Compatibility

Compatible with EpiSensor Edge over Modbus RTU

With the EKA 178A Modbus module fitted, the EKC 202 answers Modbus RTU on RS-485, which a ZMB-31 reads and sends to Edge over the EpiSensor wireless network. Danfoss publishes the parameter number of every temperature, setpoint, relay and alarm. EpiSensor's Modbus profiles for the EKC 202A and EKC 202D read the same addresses.

EKC 202A, B and C with software 1.3x, and EKC 202D with software 2.2x, each with the EKA 178A module. The EKC 202D1 is a different controller with its own parameter list and is not covered here. Site check: read the display air temperature at register 2575 and compare it with the controller display. Read-only monitoring: setpoints, defrost start, the main switch and the relays are writable parameters and stay out of the templates.

Connect it with

Route into Edge

For a cabinet or cold room controller, where a wireless link avoids a data cable back to the Gateway

  • Modbus
  • Wireless
  • Edge
  • Platforms
Refrigeration controller
Interface
Gateway
Edge
Output
EKC 202EKC 202 with EKA 178A Modbus module (RS-485)
ZMB-31Modbus RTU to the EpiSensor wireless network
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeModbus client + register map
Customer platformMQTT · API · files
Modbus RTU · RS-485
EpiSensor wireless
Runs locally
Optional onward data
Fit the EKA 178A module in the controller, wire its RS-485 pair to the ZMB-31 and give the controller a unique address in o03. Read each value with FC03 at its PNU minus 1. A ZMB reads 8 or more registers, up to 16 or more depending on the model; a ZMB-30 also has its own 2.5 m temperature probe. The customer-platform output is optional; Edge remains the local system of record.

For food safety records, measured at the warmest product position rather than at the controller's own sensor

  • Wired
  • Edge
  • Platforms
Refrigeration controller
Interface
Gateway
Edge
Output
EKC 202Cabinet or cold room, warmest product position
TES-2X probeBattery wireless temperature probe at the product, independent of the controller
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeProtocol client + point model
Customer platformMQTT · API · files
Probe in cabinet air or a product simulant
EpiSensor wireless
Runs locally
Optional onward data
Place a TES-2X probe where the warmest product sits, in air or in a product simulant. It reports independently of the controller, so a controller fault or a misplaced controller probe does not hide a warm product. Keep the controller readings beside it for diagnosis. The customer-platform output is optional; Edge remains the local system of record.

Specifications

The EKC 202 controls one refrigerated cabinet or cold room: a refrigeration relay for the compressor or liquid solenoid valve, defrost by time or temperature, evaporator fans and an alarm or light relay. The air probe drives the thermostat and the high and low temperature alarms; the S5 probe on the evaporator ends the defrost. Danfoss's fact sheet maps each EKC 202 model to an EKC 22x counterpart, but the EKC 202 is still common in installed cabinets and cold rooms.15

Controller role
Temperature and defrost control for one refrigerated cabinet or cold room1
Supply
230 V AC, 50/60 Hz, 2.0 VA1
Sensor types
Pt 1000, PTC 1000 or NTC-M2020 (5000 Ω at 25 °C), selected with o061
Measuring range
-60 to +99 °C5
Relay outputs
3 on the EKC 202B; 4 on the EKC 202C and EKC 202D5
Data communication
Modbus RS-485 with the EKA 178A module; LON RS-485 with the EKA 179A module5
Network address
o03, 0 to 119 on the EKC 202A, B and C; factory setting 01
Ambient temperature
0 to +55 °C1
Register addressing
16-bit holding registers at PNU minus 1; one-decimal values multiplied by 1036

Interface

Model

This register map applies to the EKC 202A, EKC 202B and EKC 202C.

Communication settings: EKC 202A, B and C

Protocol
Modbus RTU over RS-485
Serial format
9600 bit/s, 8 data bits, even parity, 1 stop bit, as in EpiSensor's Modbus profile
Unit address
o03, 1 to 119
PNU convention
Register address = Danfoss PNU minus 1
Temperatures
Signed 16-bit, tenths of a degree
Read with
FC03 (holding registers)
Addresses
Zero-based PDU addresses, as sent on the bus
Route into Edge
Read the display air temperature at 2575, Sair at 2588 and S5 at 1010 with FC03, signed tenths of °C. Software 1.3x parameter list.

From Modbus parameter list, EKC 202C 084B8523, SW 1.3x3.

Register map: EKC 202A, B and C

Download
PointAddressHexFormatScaleUnit
Display air temperature 2575 0x0A0F INT16 ×0.1 °C
Sair air temperature (u69) 2588 0x0A1C INT16 ×0.1 °C
S5 temperature (u09) 1010 0x03F2 INT16 ×0.1 °C
Thermostat reference (u28) 2545 0x09F1 INT16 ×0.1 °C
Cutout setpoint 99 0x0063 INT16 ×0.1 °C
Differential (r01) 100 0x0064 INT16 ×0.1 K
High alarm limit (A13) 10018 0x2722 INT16 ×0.1 °C
Low alarm limit (A14) 10019 0x2723 INT16 ×0.1 °C
Main switch (r12) 116 0x0074 INT16 ×1 -
Controller state 2006 0x07D6 UINT16 ×1 -
Defrost state 1035 0x040B UINT16 ×1 -
DI1 status (u10) 2001 0x07D1 UINT16 ×1 -
Refrigeration relay (u58) 2509 0x09CD UINT16 ×1 -
Fan relay (u59, EKC 202B and C) 2510 0x09CE UINT16 ×1 -
Defrost relay (u60, EKC 202B and C) 2511 0x09CF UINT16 ×1 -
DO4 relay status (u71) 2590 0x0A1E UINT16 ×1 -
Controller error 2540 0x09EC UINT16 ×1 -
Sair sensor error 20001 0x4E21 UINT16 ×1 -
S5 sensor error 20002 0x4E22 UINT16 ×1 -
High temperature alarm 20003 0x4E23 UINT16 ×1 -
Low temperature alarm 20004 0x4E24 UINT16 ×1 -
Door alarm 20005 0x4E25 UINT16 ×1 -
Maximum defrost time alarm 20008 0x4E28 UINT16 ×1 -

Download the EKC 202A, B and C register map as CSV

Assessment

EKC 202A, B and C (software 1.3x) and EKC 202D (software 2.2x) with the EKA 178A Modbus module

InteroperabilitySupported with conditions
Danfoss publishes a Modbus parameter number for every reading, but the RS-485 port needs the EKA 178A option module.345
AccuracySupported with conditions
Air and evaporator temperatures in tenths of a degree from the controller's own probes, which sit where the controller needs them. Food safety records need an independent probe at the product.13
SecurityNot yet assessed
Modbus RTU on a local RS-485 bus has no authentication. The cited documents describe an access code for the keypad (o05) but nothing for the bus.
ReliabilityNot yet assessed
The instructions list sensor fault codes (E27, E29) and the parameter lists carry a sensor error flag for each probe, which Edge can record beside the temperature.
RuggednessSupported with conditions
Operating ambient 0 to +55 °C for a panel-mounted controller. The cited instructions give no enclosure rating.1
ScalabilitySupported with conditions
Addresses 1 to 119 on one RS-485 bus. Each controller needs its own address and the model's own template.1
LifecycleLimited
Danfoss's fact sheet maps each EKC 202 model to an EKC 22x counterpart. Keep the software version and parameter list with each installed controller.5

Edge templates

This JSON file supplies the register map. Applying it to an existing meter replaces its sensor list while retaining the site connection, unit ID and enable state.

ModelConnectionPointsVersionUpdatedDownload
EKC 202A, B and C EKA 178A module, RS-485 Modbus RTU, Sair and S5 probes 23 1.0.0 Download
EKC 202D EKA 178A module, RS-485 Modbus RTU, S3, S4 and S5 probes, two inputs 28 1.0.0 Download

Downloads need a signed-in account with Edge download access.

Use the template in Edge

  1. Import the JSON file

    In Edge, open Settings, then Devices and Templates. Choose Import JSON and select the downloaded file. Confirm that the model and template name match your device.

  2. Load the map for your meter

    For a new Modbus device, use Load Template before entering the manufacturer or model; it fills those fields and the register list. Set the name, site connection and unit ID, check the polling enable state, then test before saving. For an existing device, apply only to the matching model; this replaces its sensor list but retains its connection, unit ID and enable state.

  3. Test a reading

    Use Test in the wizard and compare a known reading with the meter display. Check its unit, sign and scale, then confirm that timestamps keep advancing. These starter maps are read-only and leave exports off until you configure them.

Setup

Read the display air temperature

Danfoss lists the display air temperature at PNU 2576 on the EKC 202B, 202C and 202D, as a one-decimal value. The register is the PNU minus 1.

Request PDU
03 0A 0F 00 01
Address calculation
PNU 2576 minus 1 = 2575 = 0x0A0F; read one 16-bit register
Synthetic data example
00 32 = 50, × 0.1 = 5.0 °C; FF CE = -50 signed, × 0.1 = -5.0 °C
Unit
°C with r05 Temp. unit (PNU 105) at its factory setting

Acceptance: Compare the decoded value with the controller display at the same moment. The example bytes are synthetic, not a captured reply. If the value is out by a factor of ten or reads a different probe, check the address and the model's list before changing the multiplier.

  1. Fit the Modbus module

    Switch the controller off and fit the EKA 178A Modbus module. Wire its RS-485 A and B to the ZMB-31 with a twisted pair, kept apart from the mains and relay wiring. Terminate a bus of several controllers at both ends.

  2. Set the address and serial format

    Set a unique network address in o03; the factory setting is 0, so pick 1 or higher. Set the ZMB-31 to 9600 bit/s, 8 data bits, even parity and 1 stop bit, the format of EpiSensor's EKC 202 Modbus profiles.

  3. Read one temperature

    Read the display air temperature: FC03, register 2575 (PNU 2576), one register, signed 16-bit, multiplier 0.1. Compare it with the controller display at the same moment.

  4. Import the template for the model

    Import the EKC 202A, B and C template or the EKC 202D template. The two disagree on the alarm addresses, so do not mix them. Check that the defrost state and the refrigeration relay change when a defrost starts, and that o70 matches the S5 label on the EKC 202A, B and C.

  5. Add the independent probe

    For the food safety record, place a TES-2X probe at the warmest product position and keep it beside the controller readings in Edge. Set the alarm limits and delays on that probe from the site's HACCP plan.

Common questions

Which register holds the air temperature?
On the EKC 202A, B and C, the displayed air temperature is at 2575 (PNU 2576) and the Sair probe itself at 2588 (PNU 2589). On the EKC 202D, S3 is at 2529, S4 at 2530 and the thermostat air value, weighted between them by r15, at 2531. Read all with FC03 as signed tenths of a degree.34
Is the controller's air temperature enough for HACCP records?
It is a useful second signal, but the probe sits where the controller needs it, in the evaporator air, and it is there to control. A HACCP record normally wants the temperature at the warmest product position. Add an independent probe there and keep the controller's setpoint, alarms and defrost state beside it to explain an excursion. The food business operator stays responsible for the HACCP plan.18
Why does the temperature rise every few hours?
That is usually a defrost. Read the defrost state at 1035 and the defrost relay at 2511 beside the air temperature, and the rise lines up with them. The high temperature alarm has its own delay after a defrost (A12) for the same reason.13
Can Edge change the setpoint or start a defrost?
Danfoss lists the cutout setpoint, defrost start and main switch as writable parameters, but this guide and its templates read only. Changing a refrigeration setpoint affects food safety, so it needs the site's own procedure and permission, not a monitoring connection.3

Sources

  1. Instructions EKC 202A, EKC 202B, EKC 202C, RI8JV853, 06-2015 (SW 1.3x) (opens in a new tab) (PDF) Danfoss
  2. Parameter identification (Modbus), EKC 202B 084B8522, SW 1.31, RZ8CN102 (opens in a new tab) (PDF) Danfoss
  3. Modbus parameter list, EKC 202C 084B8523, SW 1.3x (opens in a new tab) (PDF) Danfoss
  4. Modbus parameters, EKC 202D 084B8536, ver. 2.2x (opens in a new tab) (PDF) Danfoss
  5. Fact sheet: EKC 202x vs EKC 22x, ERC 21x vs EKC 22x (AM446512660651en-000101, 2023.07) (opens in a new tab) (PDF) Danfoss
  6. Basic Modbus parameter list, Optyma iCO2 gateway (AU459739305217en-000201): Danfoss PNU and register convention (opens in a new tab) (PDF) Danfoss
  7. ZMB-30, ZMB-31, ZMB-33 wireless Modbus interface datasheet (EPI-195-00) (opens in a new tab) (PDF) EpiSensor
  8. TES-21, TES-22 wireless probe temperature sensor datasheet (EPI-196-00) (opens in a new tab) (PDF) EpiSensor

Further reading

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