4 recurring function test – VEGA VEGAVIB 61 - NAMUR User Manual
Page 22
Level
Signal current -
Sensor
Control lamp
Falling characteris-
tics max.
≥
2.4 mA
Falling characteris-
tics max.
≤
1 mA
Rising characteris-
tics min.
≥
2.4 mA
Rising characteris-
tics min.
≤
1 mA
Malfunction
any
≤
1 mA
flashes
6
.4 Recurring function test
According to IEC 61508.
VEGAVIB
61 is qualified in mode A (overfill protection) for use in
measuring chains of stage SIL2 according to IEC 61508 (redundant,
stage SIL3).
The following instrument combinations meet the requirements
according to SIL:
VEGAVIB
61
l
Oscillator VB60N
The recurring test according to IEC 61508 can be carried out by
pushing the simulation key on the electronics module or by briefly (> 2
seconds) interrupting the cable to the sensor. The correct sequence of
the switching conditions must be monitored via the switching amplifier
as well as the connected systems. The sensor must neither be
removed nor response must be triggered by filling the vessel. This
applies to VEGAVIB 61 with NAMUR electronics module VB60N.
SIL
Recurring function test
22
VEGAVIB
61 • - NAMUR
6 Set up
31215
-EN
-120418