11
7 Proof test
VEGASWING 66 • Two-wire (8/16
mA)
45309-EN-130722
7 Proof test
7.1 General information
To identify possible undetected, dangerous failures, the safety func-
tion must be checked in adaquate intervals by a proof test. It is the
user's responsibility to choose the type of testing. The time intervals
are subject to the PFD
AVG
in chapter "
Safety-related characteristics
".
For documentation of these tests, the test protocol in the appendix
can be used.
If one of the tests proves negative, the entire measuring system must
be switched out of service and the process held in a safe state by
means of other measures.
In a multiple channel architecture this applies separately to each
channel.
•
Determine safety function (mode, switching points)
•
If necessary, remove the instruments from the safety chain and
maintain the safety function by other means
Warning:
During the function test, the safety function must be treated as unsafe.
It must be noted that the function test influences downstream con
-
nected devices.
If necessary, you must take other measures to maintain the safety
function.
After the function test, the status specified for the safety function must
be restored.
7.2 Test 1 - without filling or dismounting the
sensor
•
Instrument in installed condition
•
Output signal corresponds to the level (covered or uncovered
vibrating element)
1.
Carry out a restart (push test key on the sensor or on the signal
conditioning instrument)
2.
Push the min./max. switch
to 1: Output of a defined starting current in three steps:
Fault message - Empty signal - Full signal (see operating instruc-
tions). Afterwards, the output signal corresponds to the level.
to 2: Output signal changes status
Remaining dangerous, undetected failures: 12
FIT (PTC
=
61
%)
Objective
Preparation
Unsafe device
status
Conditions
Procedure
Expected result
Coverage of the test
