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Objective
Preparation
Unsafe device
status
Conditions
Procedure
Expected result
Proof Test Coverage
7
Proof test
7.1
General information
To identify possible dangerous, undetected failures, the safety func-
tion must be checked by a proof test at adequate intervals. It is the
user's responsibility to choose the type of testing. The time intervals
are determined by the selected PFD
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 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 filling or dismounting the
sensor
•
Instrument in installed condition
•
Output signal corresponds to the level (covered or uncovered
vibrating element)
•
The NO contacts of the two relays connected in series must
be checked separately!
1. Carry out a restart (switch the instrument off and then on again)
2. Push the min./max. switch
to 1: Output signal corresponds to the level
to 2: Output signal changes status
See Safety-related characteristics
SITRANS LVL200H - Safety Manual
(see chapter "Safety-related
AVG
11
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