RTD measurement

In RTD measurement range, the measured resistance is internally converted to a temperature based on a set transformation. Since the channel internally measures based on 5 kΩ, the corresponding measurement error should be applied in this measuring range.

In some ranges a (relatively) higher measuring accuracy is achieved, which is why in the table below better temperature accuracy values may be specified for individual sensor types than can be calculated from the 5 kΩ accuracy1).

Please refer to the note on 2/3/4-wire measurement in the preceding chapter "Resistance".

Measurement mode

RTD

Operation mode

2.5 V feed voltage, fixed setting n +Uv

5 kΩ reference resistance at –I2

Supply current is given by:
2.5 V / (5 kΩ + Rmeasurement) → max. 0.5 mA

PDO resolution

0.01°C/digit

The transition resistance values of the terminal contacts affect the measurement. The measuring error can be reduced further through compensation by the user, with active signal connection.

The temperature end value corresponds to the nominal full scale value.

RTD measuring range

RTD measurement 1:
Chart: RTD measuring range
RTD measurement 2:

Data of the sensor types in the following table

The data of the sensor types in the following table is provided for information only and serve as help for orientation. All details of data are without warranty and have to be verified with the data sheet of the respective used sensor.

CoE Enum
RTD
Element

RTD Type

Temperature
Starting value [°C]

Temperature
End value [°C]

Achievable accuracy @ sensor temperature (full scale value). 3-wire connection(2

Achievable accuracy @ sensor temperature (full scale value). 4-wire connection(2

Temperature coefficient (terminal-specific drift)

Measured value starting value [Ω]

Measured value end value [Ω]

0

None

-

-

-

-

-

-

-

1

PT100

-200

850

±1K (-200…+850°C)

see 1)

±0.5K (-200…+850°C)

see 1)

approx. 0.13 K/K

18.52

390.48

2

NI100

-60

250

approx. ±2.68K @ 0°C

approx. ±0.83K @ 0°C

approx. 0.083 K/K

69.52

289.2

3

PT1000

-200

850

approx. ±0.38K @ 0°C

approx. ±0.13K @ 0°C

approx. 0.013 K/K

185.2

3904.8

4

PT500

-200

850

approx. ±1.03K @ 0°C

approx. ±0.34K @ 0°C

approx. 0.034 K/K

92.6

1952.4

5

PT200

-200

850

approx. ±1.96K @ 0°C

approx. ±0.65K @ 0°C

approx. 0.065 K/K

37.04

780.96

6

NI1000

-60

250

approx. ±0.34K @ 0°C

approx. ±0.11K @ 0°C

approx. 0.011 K/K

695.2

2892.6

7

NI1000 (TK5000, 100°C: 1500 Ω)

-30

160

approx. ±0.27K @ 100°C

approx. ±0.089K @ 100°C

approx. 0.009 K/K

871.7

1863.6

8

NI120

-60

320

-

-

-

80.94

461.04

9

KT100/110/130/210/230 KTY10/11/13/16/19

-50

150

approx. ±0.109K @ 0°C

approx. ±0.036K @ 0°C

approx. 0.0036 K/K

1036

4470

10

KTY81/82-110.120.150

-50

150

approx. ±0.216K @ 0°C

approx. ±0.072K @ 0°C

approx. 0.0072 K/K

515

2211

11

KTY81-121

-50

150

approx. ±0.219K @ 0°C

approx. ±0.073K @ 0°C

approx. 0.0073 K/K

510

2189

12

KTY81-122

-50

150

approx. ±0.214K @ 0°C

approx. ±0.071K @ 0°C

approx. 0.0071 K/K

520

2233

13

KTY81-151

-50

150

approx. ±0.222K @ 0°C

approx. ±0.074K @ 0°C

approx. 0.0074 K/K

502

2156

14

KTY81-152

-50

150

approx. ±0.211K @ 0°C

approx. ±0.070K @ 0°C

approx. 0.0070 K/K

528

2266

15

KTY81/82-210.220.250

-50

150

approx. ±0.108K @ 0°C

 

approx. ±0.036K @ 0°C

 

approx. 0.0036 K/K

1030

4280

16

KTY81-221

-50

150

approx. ±0.109K @ 0°C

1019

4237

17

KTY81-222

-50

150

approx. ±0.107K @ 0°C

approx. ±0.036K @ 0°C

approx. 0.0036 K/K

1040

4323

18

KTY81-251

-50

150

approx. ±0.111K @ 0°C

approx. ±0.037K @ 0°C

approx. 0.0037 K/K

1004

4173

19

KTY81-252

-50

150

approx. ±0.105K @ 0°C

approx. ±0.035K @ 0°C

approx. 0.0035 K/K

1055

4387

20

KTY83-110.120.150

-50

175

approx. ±0.222K @ 0°C

approx. ±0.074K @ 0°C

approx. 0.0074 K/K

525

2535

21

KTY83-121

-50

175

approx. ±0.224K @ 0°C

approx. ±0.075K @ 0°C

approx. 0.0075 K/K

519

2509

22

KTY83-122

-50

175

approx. ±0.221K @ 0°C

approx. ±0.074K @ 0°C

approx. 0.0074 K/K

530

2560

23

KTY83-151

-50

175

approx. ±0.225K @ 0°C

approx. ±0.075K @ 0°C

approx. 0.0075 K/K

512

2471

24

KTY83-152

-50

175

approx. ±0.216K @ 0°C

approx. ±0.072K @ 0°C

approx. 0.0072 K/K

538

2598

25

KTY84-130.150

-40

300

approx. ±0.384K @ 0°C

approx. ±0.128K @ 0°C

approx. 0.013 K/K

359

2624

26

KTY84-151

-40

300

approx. ±0.396K @ 0°C

approx. ±0.132K @ 0°C

approx. 0.013 K/K

350

2558

27

KTY21/23-6

-50

150

approx. ±0.22K @ 0°C

approx. ±0.072K @ 0°C

approx. 0.0072 K/K

518

2235

28

KTY1x-5

-50

150

approx. ±0.110K @ 0°C

approx. ±0.037K @ 0°C

approx. 0.0037 K/K

1020

4403

29

KTY1x-7

-50

150

approx. ±0.107K @ 0°C

approx. ±0.036K @ 0°C

approx. 0.0036 K/K

1052

4537

30

KTY21/23-5

-50

150

approx. ±0.220K @ 0°C

approx. ±0.073K @ 0°C

approx. 0.0073 K/K

510

2202

31

KTY21/23-7

-50

150

approx. ±0.214K @ 0°C

approx. ±0.071K @ 0°C

approx. 0.0071 K/K

526

2268

1) Achievable at negligible offset part, e.g. through cross reference offset correction/ zero offset (ELM3xxx: zero offset function).

Higher measuring accuracy for individual sensor types whose resistance is in the smaller subrange of 0..5 kΩ.

2) Relative error according to the slope of the respective RTD characteristic diagram at 23°C ambient terminal temperature (not taking into account temperature drift of the sensor).

Notice

Extended Range mode not available

The Extended Range mode is not available for RTD measurement.

    • Until FW07: Object 0x8000:2E (Scaler) will be ignored by this setting. The “Legacy Range Mode” applies in the background.
    • From FW08: Object 0x8000:2E (Scaler) will then be set to the “Legacy Range Mode”. A change is not possible as long RTD measurement range is selected.