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Final inspection

Delivery inspection "3.1"

As far as it is physically possible temperature sensors are tested individually before delivery. The test results are reported in a test certificate according to the EN 10204 3.1 standard. The serial number of the label attached to the individual sensor shows that the sensor has passed the test. See below. Certificates issued in 2005 and later can be searched for in section Test certificates.

Tracability

At the delivery test equipments are used whose properties are traceable to
Pentronic’s accredited laboratory. The traceability is maintained by procedures of our ISO 9001 quality assurance system. The testing procedures are elaborated by the staff of the accredited laboratory that also supervises the delivery testing.

9001-14001-blue-w100

Delivery test of temperature sensors

All temperature sensors manufactured by Pentronic must pass the delivery test station which occupies the spaces next to the accredited laboratory. Thus the activities can easily be supervised by the laboratory staff. Sample tests is nothing for us - we test all sensors. Different sensor types require different test methods though all the test equipment is traceably calibrated at our accredited laboratory. Test reports are saved individually and can be reached by sensor serial number or Pentronic’s order number via Test certificates in the navigation list.

Principally the delivery-test calibration is performed as in the accredited laboratory.  Exceptions are shorter series of measured values and sometimes very short insertion lengths which both will cause larger measurement uncertainties.

Delivery _checkout _1

Work at Pentronic’s delivery test stations. Foreground: The insulation of a number of Pt100 sensors is tested simultaneously as they gradually are approaching 0 °C in the ice-water bath.

Test operation

The delivery test contains five operations:
1: Visual inspection
2: Physical dimensions 
3: Measurement of output signall 
4: Isolation test
5: Marking and numbering

Certificate according to ”3.1”

When physically possible the individual measurement value of every sensor is reported in a test certificate according to EN 10204 3.1 which is saved at Pentronic. The traceability is secured by attaching a label marked with a serial number of the sensor.

Testing sensor types sensitive to water or steam we take samples from every manufactured batch. Then the samples are put into a protective tube to check that they are working properly.

Customer-suited tests

It is getting more and more common that customers ask for testing at temperatures significant to their processes. As a result of this we offer calibration, testing and marking quite suited to the customers’ demands.

Final _inspection _labels

Labels with serial number are attached
to sensors individually. If required other types of labelling are available.

 

Thermocouples

Output signal

Thermocouples are measured at 100 °C with the “cold junction” at 0 °C. The output signal is normally compared to the standard IEC 60584-2 class 1. For thermocouple types K and N this means a tolerance of ± 1,5 °C at 100 °C.

Electric isolation

The isolation test, when applicable, is performed in room temperature and is suited to the sheath diameter, D, of the thermocouple. See table below. Pentronic’s isolation test normally fulfills the demands of the IEC 61515 (1995).

Requirements of isolation are also specified by the ASTM E608 (2000) but this standard uses lower voltages and requires lower resistances. It should be pointed out that the insulation resistance decreases with increasing temperature.

 
Isolation requirements -
metal sheathed thermocouples 
according to the IEC 61515 (1995)

Probe diameter
D
 (mm)

Test voltage
(VDC)

Requirement at room temperature
(Mohm)

< 1,5

75 ± 25

1000

D > 1,5

500 ± 50

> 1000

Icewater _bath

Pt100 sensors are normally tested at 0 °C. It is neccessary to measure the temperature of the ice bath. This is done
continuously with a platinum reference
sensor which is visible two pictures below.

 

Pt100s (RTDs)

Output signal

Pt100 sensors are tested in 0 °C without outer protection tube. The result shall very well fit within the requirements, e. g. ± 0,15 °C as per IEC 60751 class A.


Electric isolation

Pentronic checks the isolation inbetween 0 C and room temperature, normally by applying 500 VDC requiring at least 1000 Mohms resistance.

IEC 60751 requires at room temperature only 10 - 100 VDC and at least 100 Mohms resistance. It should be pointed out that the isolation resistance decreases with increasing probe temperature.



Final _inspection _2

Visual inspection of thermocouples suited
for a certain customer’s needs.

Delivery _checkout

Isolation test in connection with the
calibration at 0 °C of Pt100s. The refe-
rence sensor can be seen on the left-
hand side of the ice-water bath.

 

 Accredited calibration by delivery 

Accredited calibration of temperature sensors

If the customer requests the delivery test to be carried out as an accredited calibration, the sensors will be delivered including a formal Accredited Calibration Certificate where the traceability to the temperature scale is guaranteed.

Accredited calibration of instruments

On request instruments can be delivered including a calibration certificate from the Accredited Laboratory of Pentronic. 

System calibration

We recommend so called system calibration where the instrument is connected to one or more temperature sensors. This method will reduce the measurement uncertainty of the calibration compared to individual calibration of all included parts.

AKL17025v2

Certificate _thermometer

Example of sensor and temperature indicator which are system calibrated. Swedac's symbol in the upper
left corner of the certificate shows that the calibration is performed under accreditation.