11
7 Proof test
VEGAFLEX 80 series • 4 … 20 mA/HART - two-wire
42960-EN-140924
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
•
Provide an approved adjustment unit
Warning:
During the function test, the safety function must be treated as unreli-
able. Take into account that the function test influences downstream
connected 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 checking the level
•
Instrument in installed condition
•
Distance from the sensor reference point to the level > 300 mm
•
Output signal corresponds to the level
•
Device status in the menu Diagnosis: "
OK
"
1. Carry out a restart (switch the instrument off and then on again)
2. Press the menu item "
Start proof test
" in the menu Diagnosis on
the adjustment unit
•
To 1:
– Output signal corresponds to the level
– Device status in the menu Diagnosis: "
OK
"
•
To 2:
– Adjustment unit signals "
Test successful
"
Remaining dangerous, undetected failures: 11 FIT (PTC = 93 %)
7.3 Test 2 - with checking the level
•
Instrument in installed condition
•
Distance from the sensor reference point to the level > 300 mm
•
Output signal corresponds to the level
Objective
Preparation
Unsafe device
status
Conditions
Procedure
Expected result
Coverage of the test
Conditions
Summary of Contents for VEGAFLEX 80
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