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Thermal Validation Hardware

Anville Series 825 thermal validation interface

The Anville Series 825 TVI is designed for use with EaziVal SE software. Anville's thermal validation systems can be used wherever it is necessary to maintain a formal record to prove that the correct temperatures and pressures have been achieved during a critical process. Anville understand that equipment testing and validation are undertaken by busy engineering staff and have concentrated on making Eazival SE easy to setup and use.


The Anville Series 825 TVI differs from the majority of data loggers by the design of the thermocouple input connection, associated thermocouple cold junction compensation and in the use of analogue input parallel processing enabling the unit to have a acquisition rate of better than once per second for all inputs. The Series 825 TVI uses individual high speed amplification and analogue to digital conversion on each input channel with conversion to engineering units (°C/°F) carried out by the internal microcontroller. Data is communicated to the computer in the correct engineering units enabling the system to have a traceable calibration certificate. The Series 825 TVI has an internal power supply to provide a 20VDC excitation voltage for the 4-20mA inputs and no separate power supply is required for a loop powered transducer.


In the Anville Series 825 TVI all cold junction compensation errors are minimised by using correctly compensated miniature type T thermocouple connectors with matching class 1 thermocouple wiring to the internal cold junction sensor. A 1/3 DIN Pt100 sensor measures the cold junction temperature to an accuracy of ±0.1°C at 0°C. Design of the physical layout of the cold junction reduces any thermal scatter to a typical deviation of ±0.05°C.


The Anville Series 825 measurement range for type T thermocouples is -200°C to 300°C with a resolution of 0.01°C. Over a measurement range from -50°C to 300°C the overall system accuracy is ±0.25°C. This accuracy is maintained over an ambient operating temperature range from 0°C to 50°C and includes all errors due to thermocouple cold junction compensation, DC amplification, A/D conversion and thermocouple linearisation.


The Series 825 TVI accuracy of ±0.25°C is a worst case "out of the box" value including all system errors but excluding thermocouple sensor error.

Specifications


 Series 825 TVI
Type T thermocouple inputsChannels 1-16
4-20mAChannels PR1 & PR2

 Measurement rangeAccuracyResolution
Type T thermocouple input-50.0°C to 300.0°C±0.25°C0.01°C
Type T thermocouple input-200.0°C to -50.0°C±1.0°C0.01°C
Transducer input4-20mA±0.1%1µA

Scanning speedAll channels in less than 1 sec.
Transducer power supply (internal)20VDC
Operating ambient temperature0°C to 50°C

 Series 825 TVI
Dimensions W x H x D240mm x 140mm x 290mm
Weight4kg

Anville Series 825 TVI measurement uncertainty


Calibration of the complete measurement system of thermocouples, data logger and software against a UKAS reference thermometer each time the equipment is used reduces all errors, systematic and random, at the moment of calibration. Any measurements subsequently made with the complete measurement system have to be qualified by a statement of measurement uncertainty.

EN554, EN285, HTM2010 and HTM2030 (Scotland) require that the repeatability of measurement should be ±0.25°C or better and that the combined uncertainties of the complete measurement system, including sensors, should not exceed ±0.5°C. The measurement uncertainty is calculated using a statistical approach giving a final value at a 95% confidence level with a Gaussian distribution. Measurement uncertainty is a function of the equipment specification and characteristics and cannot be changed by any subsequent calibration.


Source of uncertaintyValueProbability distribution

DivisorSQRT(3)

Total value / SQRT(3)Total ^ 2
Resolution0.010°CRectangular1.732050810.005773500.00003333
Drift of unit & thermocouples0.100°C Rectangular1.732050810.057735030.00333333
Range accuracy0.250°CRectangular1.732050810.144337570.02083333
Stability vs. ambient temperature0.100°CRectangular1.732050810.057735050.00333333
Drift with use0.100°CRectangular1.732050810.057735050.00333333
Cold junction error0.150°CRectangular1.732050810.086602540.00750000
Repeatability0.100°CRectangular1.732050810.057735050.00333333

Combined (sum of all inputs)0.04170000°C
66% combined uncertainty (SQRT of sum)0.20420578°C
UKAS 95% confidence0.40841156°C