VEGA VEGAFLEX 86 4 … 20 mA_HART two-wire Rod and cable probe With SIL qualification User Manual

Page 88

12 Supplement

VEGAFLEX 86 • 4 … 20 mA/HART two-wire

44234-EN-130823

Specifications apply also to the current output

Temperature drift - Current output

±0.03 %/10 K relating to the 16 mA span max. ±0.3 %

Deviation on the current output through

analogue/digital conversion

< ±15 µA

Additional deviation through electromag-

netic interference acc. to EN 61326

< ±150 µA

Influence of the superimposed gas and pressure to the accuracy
The propagation speed of the radar impulses in gas or vapour above the medium is reduced by

high pressure. This effect depends on the superimposed gas or vapour and is especially large at

low temperatures.
The following table shows the resulting deviation for some typical gases and vapours. The specified

values refer to the distance. Positive values mean that the measured distance is too large, negative

values that the measured distance is too small.

Gas phase

Temperature

Pressure

10 bar

(145 psig)

50 bar

(725 psig)

100 bar

(1450 psig)

200 bar

(2900 psig)

400 bar

(5800 psig)

Air

20 °C/68 °F

0.22 %

1.2 %

2.4 %

4.9 %

9.5 %

200 °C/392 °F 0.13 %

0.74 %

1.5 %

3.0 %

6.0 %

400 °C/752 °F 0.08 %

0.52 %

1.1 %

2.1 %

4.2 %

Hydrogen

20 °C/68 °F

0.10 %

0.61 %

1.2 %

2.5 %

4.9 %

200 °C/392 °F 0.05 %

0.37 %

0.76 %

1.6 %

3.1 %

400 °C/752 °F 0.03 %

0.25 %

0.53 %

1.1 %

2.2 %

Steam (satu-

rated steam)

100 °C/212 °F -

180 °C/356 °F 2.1 %

264 °C/507 °F 1.44 %

9.2 %

366 °C/691 °F 1.01 %

5.7 %

13.2 %

76.0 %

Characteristics and performance data
Measuring cycle time

< 500 ms

Step response time

≤ 3 s

Max. filling/emptying speed

1 m/min

Ambient conditions
Ambient, storage and transport tempera-

ture

-40 … +80 °C (-40 … +176 °F)

Process conditions
For the process conditions, please also note the specifications on the type label. The lowest value

always applies.
The measurement error from the process conditions is in the specified pressure and temperature

range of below 1 %.

Also for the second current output (optional)

Time span after a sudden measuring distance change by max. 0.5 m in liquid applications, max 2 m with bulk

solids applications, until the output signal has taken for the first time 90 % of the final value (IEC 61298-2).