KROHNE SU 501 EX EN - Manual (Page 28)

9.3 Setup
The prevailing plant conditions influence the safety of the
measuring system. Therefore note the mounting and installa-
tion instructions of the appropriate operating instructions
manual. Mainly important is the correct setting of the mode
(min./max.).
9.4 Reaction during operation and in case of
failure
l
The adjustment elements must not be modified during
operation.
l
In case of modifications during operation, you have to take
note of the safety functions.
l
Occurring fault signals are described in the appropriate
operating instructions manual.
l
In case of detected failures or fault signals, the entire
measuring system must be switched out of service and the
process held in a safe condition by means of other
measures.
l
The manufacturer must be informed if due to a determined
fault, the instrument will be exchanged (incl. a fault
description)
9.5 Recurring function test
The recurring function test serves to reveal potential danger-
ous errors that are otherwise not discernible. The function of
the measuring system must be checked at adequate intervals.
The operator is responsible for choosing the type of test and
the intervals in the stated time frame. The time frame depends
on the PFD
avg
value acc. to the chart and diagram in section
"Safety-related characteristics".
With high demand rate, a recurring function test is not
requested in IEC 61508. The function of the measuring system
is proven by the frequent use of the system. In double channel
architectures it is useful to proof the redundancy by recurring
function tests in appropriate intervals.
The test must be carried out in a way that verifies the flawless
operation of the safety functions in conjunction with all system
components.
Mounting and installation
28 SU 501 Ex - Signal conditioning instrument
Functional safety
27953
-EN
-050616