Danfoss EKC 313 User guide

User Guide

Controller for cascade systems
with CO

2

EKC 313

ADAP-KOOL® Refrigeration control systems

Introduction

Danfoss

Application

The controller can be used in systems with cascade regulating and
CO2 as refrigerant on the low temperature circuit.
It regulates the cooling of the heat exchanger to optimise super­heat.

Advantages

• Dedicated cascade controller

System

The controller must receive a signal from two pressure transmit­ters and two temperature sensors. The pressure transmitters must
have a type AKS 32R or AKS 2050 ratiometric output signal, as
determined by the actual pressure conditions. The signal from the
pressure transmitters can be a voltage signal of either 0-10 V or
1-5 V.
Type AKS 11 temperature sensors can be used, but type AKS 21
must be used if the temperature exceeds 100°C.

Functions

Output signal

The controller has a voltage output on 0-10 V.
The signal can be used for:

• Indicating the valve's opening degree when using an ETS valve

• Controlling the valve when using an ICAD/ICMTS valve

Valves opening degree

The valve's opening degree can be limited.

Relay

The relay in the controller can be used for:

• Alarm relay

• Control of solenoid valve in liquid line

Start/stop

A switch can be connected for starting and stopping the regula­tion.

PC-operation

The controller can be provided with data communication so that it
can be connected to other products in the range of ADAP-KOOL®
refrigeration controls. In this way operation, monitoring and data
collection can be performed from one PC – either on the spot or in
a service company.

84B2959.10

Contents

Introduction ....................................................................................................... 2

Example ............................................................................................................... 3

Function overview ........................................................................................... 4

Operation ............................................................................................................ 8

2 User Guide RS8FZ402 © Danfoss 2015-07 EKC 313

Menu survey ....................................................................................................... 8

Connections ..................................................................................................... 10

Data ..................................................................................................................... 11

Ordering ............................................................................................................11

Example

Optimised superheat regulation with limit if the condensing pressure is low.

Optimised superheat regulation is used when the condensing
pressure is above the set value.
If the condensing pressure falls below the set value, the opti­mised superheat regulation ceases and the ETS valve closes
gradually until the pressure rises above the value.

EKC 313 User Guide RS8FZ402 © Danfoss 2015-07 3

Function overview

Function Para-

meter

Normal display

Displays either the valve's actual opening degree or the actual superheat value.
(Desired value can be set in o17)
Briey pushing the bottom button will display one of the two readings.
Briey pushing both buttons will display the superheat reference (u22).

Control parameters Injection control

Start/stop of regulation

This setting can be used to start and stop regulation.

I: Integration time Tn

If the Tn value is increased the regulation becomes slower

Lower limit value for the condensing pressure.

If the pressure falls, the valve will start closing.

Max. opening degree

The valve's opening degree can be limited here.
The setting is expressed as a % of the total opening degree. The voltage signal of 0-10
V on the output will be limited correspondingly.

Amplication factor for the superheat

This setting determines the valve’s opening degree as a function of the change in
evaporating pressure. An increase of the evaporating pressure will result in a reduced
opening degree. When there is a drop-out on the low-pressure thermostat during
start-up the value must be raised a bit. If there is pendling during start-up the value
must be reduced a little.
The value should only be changed by specially trained sta.

Kp value for amplication factor for PID regulation n95 Kp Max

Parameter by operation via
data communication

u24 /

Valve OD %

u21

SH

r12 Main Switch

n05 Tn sec.

n98 Tc Ref

n32 OD% Max

n20 Kp T0

Kp value near reference value

Just around the reference this value will be used in stead of the "n95 value"
The value should only be changed by specially trained sta.

Signal safety during start-up

The control function uses the value as start value for the valve’s opening degree at
each thermostat cutin. By adaptive control the controller continuously calculates a
new value.
The value should only be changed by specially trained sta.

Start-up time for safety signal

If the controller does not obtain a reliable signal within this period of time the con­troller will in other ways try to establish a stable signal. (A too high value may result in
a ooded evaporator).
The value should only be changed by specially trained sta.

MOP

If no MOP function is required, select pos. O. (A value of max. (60) will correspond to
O)

Min. value for the superheat reference n10 SH Min

Max. value for the superheat reference n09 SH Max

D: Dierentiation time Td n06 Td sec

n19 Kp Min

n17 Start OD%

n15 StartUp time

n11 MOP (bar)

4 User Guide RS8FZ402 © Danfoss 2015-07 EKC 313