VEGA VEGABAR 61 Foundation Fieldbus - Manual (Page 54)

Channel Numbers
-
Channel 1 Primary Value
-
Channel 2 Secondary Value 1
-
Channel 3 Secondary Value 2
-
Channel 4 Temperature Value
Transmission rate 31.25 Kbit/s
Current value 10 mA, ±0.5 mA
Dynamic behaviour output
Run-up time approx. 10 s
90 %
100 %
10 %
t
t
T A
t
t
S
2 1
Fig. 28: Sudden change of the process variable, dead time t
T
, rise time t
A
and step response time t
S
1 Process variable
2 Output signal
Dead time ≤ 150 ms
Rise time ≤ 100 ms (10 … 90 %)
Step response time ≤ 250 ms (ti: 0 s, 10 … 90 %)
To this amounts the reaction time of the isolatng system. This time varies from values < 1 s with
compact isolating diaphragms up to several seconds with capillary systems.
Example: Flange isolating diaphragm DN 80, filling silicone oil KN 2.2, capillary length 10 m,
measuring range 1 bar
Process temperature Reaction time
40 °C approx. 2 s
20 °C approx. 3 s
-20 °C approx. 11 s
Damping (63 % of the input variable) 0 … 999 s, adjustable
54 VEGABAR 61 • Foundation Fieldbus
10 Supplement
28258
-EN
-081209