VEGA VEGAVIB 67 - two-wire - Manual (Page 24)

Mode on the
signal condi-
tioning in-
strument
Level Signal cur-
rent - Sen-
sor
Signal lamp
- sensor
Signal
lamp - sig-
nal condi-
tioning in-
strument
Fault signal
(mode A/B)
any <2.3 mA
flashes red
6.4 Recurring function test
According to IEC 61508.
VEGAVIB 67 Ex in conjunction with a VEGATOR 636 Ex 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 67 EX
l
Oscillator VBE60Z (EX)
l
VEGATOR 636EX signal conditioning instrument
The recurring function test according to IEC 61508 can be
carried out by pushing the test key on the signal conditioning
instrument or by briefly (>2 seconds) interrupting the cable to
the sensor. The correct sequence of the switching conditions
must be monitored via the two LEDs on the signal conditioning
instrument 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 67 with two-wire oscillator
VBE60ZEX.
You can carry out the function test with the outputted current
values also directly with a safety PLC or a process control
system.
The implementation and switching sequence of the function
test is described also in the operating instructions manual of
the appropriate signal conditioning instrument.
A function test can be carried out for measuring systems in
conjunction with the two-wire oscillator VB E60Z EX. Therefore
the integration time must be set to 0.5 s. The signal
conditioning instrument has an integrated test key. The test
SIL
Recurring function test
Test key on the signal con-
ditioning instrument
24 VEGAVIB 67 - with two-wire output
Set up
29298
-EN
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