Danfoss Electronic Controls Service guide

MAKING MODERN LIVING POSSIBLE

Electronic Controls

Fitter’s Notes

www.danfoss.com

Fitter notes – Electronic Controls

2 DKRCC.PF.000.G2.02 / 520H8626

Fitter notes – Electronic Controls

Contents

Measuring 4

Measuring a temperature 4
Temperature sensor type EKS 111 5
Temperature sensor type EKS 211 5
Positioning sensors 6
Evaporator positions 6
S1 and S2 sensors 7
How to mount S2 sensor on a vertical pipe 7
How to mount S2 sensor on a horizontal pipe 7
Measuring a pressure 8
Positioning sensors 11
Pressure transmitter in liquid line with pulse snubber 12

Electrical connections 13

Pulse width modulation electronically operated expansion valve type AKV 13
Stepper motor electronically operated expansion valve type ETS 13
Digital Input (DI) / Digital Output (DO) 14
No power 14
Split sensors and AKV 14
External Start/Stop of regulation 14

Controlling 15

Input and output 15
Op eratio n 15
Evaporator controls 16
Parameters 16
What is the controller doing...? 17
Quick start 17

What is wrong....? 18

Communication 19

Why...? 19
How…? 19
Cable selection / termination 20
Requirement to installation 20
Cable 21
Addressing 24
Trouble shooting 24

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Fitter notes – Electronic Controls

R

NTC

PTC

Pt

T

Measuring

Measuring a temperature

Pressure temperature inputs

With the use of electronic controllers such as
Danfoss ADAP-KOOL® products the installation requirements must
be followed to ensure the electrical connections, pressure and
temperature sensors and any communication network
connections are correct so that the unit operates as intended.
The following are some general guidelines:

y Pressure temperature inputs

It is very important that the correct type of temperature sensor
is used for the temperature range, sensing application, and the
temperature sensor signal is compatible with the electronic
refrigeration controller, (please see the technical manual for the
controller to ensure the correct temperature sensor is used).

y Sensor types

The product programme of temperature sensors for
refrigeration consists of two main families: AKS and EKS.
These sensor elements are based on the three technologies:
Pt, PTC and NTC.

Temperature sensor type:
AKS11, AKS12, AKS21, AK-HS 1000

Pt sensor

These sensors are also known as RTD´s, Resistance Temperature
Detectors. The sensing elements is made of platinum, example

PT1000, where the number describes the nominal resistance at
0°C, here 1.000Ω. The resistance increases 4Ω per 1°C. The sensor
characteristic is linear. In Danfoss these sensors are the type AKS.
The tolerance of a Pt1000 sensor is less than ± (0.3 + 0.005 T).
This translates into a temperature error of less than 0.5 degree for
refrigeration control.
The Pt1000 sensor must be used for food safety logs and
regulation of superheat as they conform to the tolerance
requirements of EN 60751 Class B and therefore satisfy the HACCP
requirements of EN 12830, EN 13485.

Extension of sensor cables

When extending a sensor cable, the new resistance value of the
longer cable may give rise to indication error. It is recommended
that the total cable resistance should not exceed 2Ω
corresponding to an indication error of 0.5°C (Pt1000Ω).

Note

Up to 50m use 0.75mm²
Up to 100m use 1.5mm²
Up to 150m use 2.5mm²

The typical resistance values for cables are:

y -2.4Ω/100m for core cross-sectional area of 0.75mm².
y -1.2Ω/100m for core cross-sectional area of 1.5mm².
y -0.7Ω/100m for core cross-sectional area of 2.5mm² .

AKS 11, AKS 12, AKS 21, AK-HS 1000

°C ohm °C ohma

0 1000.0 1000.0

1 1003.9 -1 996.1
2 1007.8 -2 992.2
3 1011.7 -3 988.3
4 1015.6 -4 984.4
5 1019.5 -5 980.4
6 1023.4 -6 976.5
7 1027.3 -7 972.6
8 1031.2 -8 968.7
9 10.35.1 -9 964.8
10 1039.0 -10 960.9
11 1042.9 -11 956.9
12 1046.8 -12 953.0
13 1050.7 -13 949.1
14 1054.6 -14 945.2
15 1058.5 -15 941.2
16 1062.4 -16 937.3
17 1066.3 -17 933.4
18 1070.2 -18 929.5
19 1074.0 -19 925.5
20 1077.9 -20 921.6
21 1081.8 -21 917.7
22 1085.7 -22 913.7
23 1089.6 -23 909.8
24 1093.5 -24 905.9
25 1097.3 -25 901.9
26 1101.2 -26 898.0
27 1105.1 -27 894.0
28 1109.0 -28 890.1
29 1112.8 -29 886.2
30 1116.7 -30 882.2
31 1120.6 -31 878.3
32 1124.5 -32 874.3
33 1128.3 -33 870.4
34 1132 -34 866.4
34 1132.2 -34 866.4
35 1136.1 -35 862.5
36 1139 -36 858.5
37 1143.8 -37 854.6
38 1147.7 -38 850.6
39 1151.5 -39 846.7
40 1155.4 -40 842.7
41 1159.3 -41 838.8
42 1163.1 -42 835.0
43 1167.0 -43 830.8
44 1170.8 -44 826.9
45 1174.7 -45 822.9
46 1178.5 -46 818.9
47 1182.4 -47 815.0
48 1186.3 -48 811.0
49 1190.1 -49 807.0
50 1194.0 -50 803.1

approx 3.9 ohm/K

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Fitter notes – Electronic Controls

Temperature sensor type EKS 111

PTC sensor

The PTC sensor got their name as the sensing element has a
positive temperature coecient.
The sensing element is a semi conductor, example PTC1000
where the number describes the nominal resistance at 25°C.
The sensor characteristic is almost linear but is not standardized,
the manufacturer can dene their own characteristics.

In Danfoss the EKS111 is a PTC1000 type.
The PTC temperature sensor type EKS111 must not be used for
food safety logs as they do not conform to the requirements
EN 12830, EN 13485 or regulation of superheat because they do
not have the needed accuracy of +/- 0.5K.

R (typ.) Ohm Tem p. °C Error K Te mp ° F

1679 100 +/-3.5 212

1575 90 194

1475 80 176

1378 70 15 8

128 6 60 14 0

119 6 50 12 2

1111 40 104

1029 30 86

990 25 +/-1.3 77

951 20 68

877 10 50

807 0 32

740 -10 14

677 -20 -4

617 -30 -2 2

562 -40 -40

510 -50 -58

485 -55 +/-3.0 - 67

Temperature sensor type EKS 211

NTC sensor

The sensing element in NTC´s is a thermistor having a
negative temperature coecient.
The sensor characteristic is described by a number, that as with
PTC´s, indicates the nominal resistance at 25°C, and by a β-value
which denes the curve characteristic.
Due to the variety of characteristics it is not possible to develop a
standard NTC sensor that can be used for all controller types.
Hence, when making service you must install an “original” NTC
sensor to ensure the controller to work properly.

Temperature sensor type EKS 211

NTC characteristic matches controllers type EKC and AK-CC.
The NTC temperature sensor type EKS211 must not be used for
food safety logs as they do not conform to the requirements
EN 12830, EN 13485 or regulation of superheat because they do
not have the needed accuracy of +/- 0.5K.

R_nom Ohm Tem p. °C Temp °F

631.0 80 176

743.2 75 167

878.9 70 158

104 4 65 149

1247 60 14 0

1495 55 131

1803 50 12 2

2186 45 113

2665 40 104

3266 35 95

4029 30 86

5000 25 77

6246 20 68

7855 15 59

9951 10 50

12696 5 41

16330 0 32

21166 -5 23
27681 -10 14

36503 -15 5

48 614 -20 -4

65333 -25 -13

88766 -30 -22

12179 5 -35 - 31

16915 7 -40 -40

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Fitter notes – Electronic Controls

Positioning sensors

It is very important that during the installation process and also
during maintenance schedules the correct position and mounting
of all temperature sensors is in line with the recommendations.
Incorrect mounting can cause faulty temperature signals to be
used by the controller which will result in, in-correct operation of
the refrigeration application.

Ø=

Ø=

125

in.

8

12 - 16mm

341

1

8

18 - 26mm

in.

12

1

2

3

4

12

1

2

3

4

Evaporator positions

Nomenclature of temperature tensors & pressure
transmitters in Danfoss controllers

y S1: Temperature sensor measuring evaporating temperature

(Can be used as a less accurate measurement of
evaporating temperature without the need for a pressure
transmitter)

y Pe: Pressure transmitter measuring true evaporating pressure

(preferred method)

y S2: Suction temperature outlet of the evaporator
y S3: Air entering the evaporator
y S4: Air leaving the evaporator
y S5: Defrost termination temperature sensor when defrost is

being used

y S6: Is used as a product sensor (type AK-HS1000,HACCP

compliance for food safety)

Pack positions

y Po: Pressure transmitter - Suction pressure
y Pc: Pressure transmitter - Discharge pressure
y Ss: Temperature sensor - Suction temperature to work out

suction superheat in connection with suction pressure Po

y Sd: Temperature sensor - Discharge temperature
y Sc3: Temperature sensor - Ambient temperature of the air

entering the condenser

Ø=6.5

S6 S4

M M

S3

Po Pc

S

S

NB!

Pe

S2

S5

Sd

S

CS

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Fitter notes – Electronic Controls

S1 and S2 sensors

S1 and S2 sensors measuring saturation temperature and
temperature of superheat gasses.

y S1: This sensor is measuring the evaporating temperature of

the evaporator and therefore must be mounted on the
coldest point on the evaporator, normally the rst return
bend.
The reading should be checked against the suction gauge
pressure to conrm that the pressure and temperature
relationship is correct otherwise the control of superheat
will be incorrect.

Where and how to mount the S1 sensor

S1

S1S1A

S1

B

B

y S2: Sensor function is to measure the temperature of the

refrigerant exiting at the evaporator’s pipe outlet and, has
thus, the same goal as a thermostatic expansion valve’s
bulb and should be placed exactly according to the same
rules.
Only a Pt1000 AKS11 type sensor must be used, as it is the
only type providing the necessary accuracy needed for
this purpose.

How to mount S2 sensor on a vertical pipe

Steel pipes

If steel pipes are used on the evaporator outlet the superheat
signal it must be measured using a pocket sensor “S2” to get a
correct signal. This is absolutely necessary to get a good injection
control.

Copper pipes (exceeding 50mm)

When pipe dimensions go up so does the material thickness.
Bigger thickness also means greater temperature dierence
between inner and outer temperatures. You should use
immersion pocket sensors here also.

Where and how to mount the S2 sensor

Mount on vertical pipe if possible not too close to bend
and not to far from evaporator outlet

AA

Cut A-A

Cut A-A

A

S2

S2 B

The sensor should be
mounted rmly on the
pipe using heat-conducting
paste and the sensor
should be insulated

S2

Pipe isolation

S2 sensor

Oil splash can disturb the signal

How to mount S2 sensor on a horizontal pipe

The sensor should be

When mounted on horizontal pipe the position depends on the
size of the pipe.

y Mount at 1 o’clock when diameter is between 1/2 and 5/8inch

(12-16mm).

y Mount at 2 o’clock when diameter is between 3/4 and

1- 1/8inch (18-26mm).
y Mount at 4 o’clock when diameter is over 1- 1/2inch (38mm).
y Use immerse pocket sensor if you want to measure on steel

pipe.

B

B

Cut B-B

mounted rmly on the
pipe using heat-conducting
paste and the sensor
should be insulated

S2

S2 sensor

Pipe

Isolation

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Fitter notes – Electronic Controls

Measuring a pressure

It is very important that the correct type of pressure transmitter is
used for the pressure range, sensing application, and the pressure
transmitter signal is compatible with the electronic refrigeration
controller, (please see the technical manual for the controller to
ensure correct pressure transmitter is used).

AKS ratiometric

Typ e Operating range [bar] Permissible working pressure

AKS 2050 -1 to 59 100

-1 to 99 150

-1 to 159 250

PB [b ar]

AKS 32, ver sion 1-5V

Operating range Max working pressure PB

LP

HP

AKS 32, ver sion 0-10V

LP

HP

AKS 33, version 4-20mA

LP

HP

-1 --> 6 [bar] 33 [bar]

-1 --> 12 [bar] 33 [bar]

-1 --> 20 [bar] 40 [bar]

-1 --> 34 [bar] 55 [bar]

Operating range Max working pressure PB

-1 --> 5 [bar] 33 [bar]

-1 --> 9 [bar] 33 [bar]

-1 --> 21 [bar] 10 [b ar]

-1 --> 39 [bar] 60 [bar]

Operating range Max working pressure PB

-1 --> 5 [bar] 33 [bar]

-1 --> 6 [bar] 33 [bar]

-1 --> 9 [bar] 33 [bar]

-1 --> 12 [bar] 33 [bar]

-1 --> 20 [bar] 40 [bar]

-1 --> 34 [bar] 55 [bar]

0 --> 16 [bar] 40 [bar]

0 --> 25 [bar] 4 0 [bar]

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