Samson 3738-20, Mounting And Operating Instructions

Page: 14 / 84

14 EB 8390 EN
Design and principle of operation
The function is suitable for use in safety-in-
strumented systems up to SIL 2 (single chan-
nel) and SIL 3 (redundant configuration) ac -
cording to IEC 61508.
Note:
Safety-related end position monitor-
ing and emergency venting work in-
dependently from one another to
meet the device design requirements
to conform with SIL.
Requirements
−
Short mean time to repair compared to
the average rate of demand
−
Normal exposure to industrial environ-
ment and fluids
−
The user is responsible for ensuring that
the device is used as intended.
Useful lifetime
According to IEC 61508-2, section 7.4.9.5,
a useful lifetime of eight to twelve years can
be assumed. Other values can be used
based on the user’s previous experience (pri-
or use/proven-in-use).
Notes concerning diagnostics
−
Diagnostics are performed cyclically in-
side the device. Critical errors (device er-
ror E9) are indicated by contact B as
wire breakage according to
DIN EN 60947-5-6. Existing errors must
be remedied as described in these
Mounting and Operating Instructions. If
this is not possible, the electronic limit
switch must not be used in safety loops.
− The proper functioning of the display can
be verified over P3 parameter (see sec-
tion 8.2).
− The correct setting of all parameters must
be verified before every start-up.
Proof testing
All switching contacts need to be activated
for the proof test. This can be done by:
−
Using the mounted actuator to move the
valve to the end position
− Simulating the outputs using P19 param-
eter (see section 9.4).
During the proof test, check that the outputs
switch properly.
Intended use
The specifications and information in the da -
ta sheet and in these instructions must be ob-
served.
Note concerning diagnosis of connected so-
lenoid valve and actuator
The diagnostics functions performed in the
device, e.g. actuator transit time monitoring,
are suitable for diagnosis of connected de-
vices, such as solenoid valve, pneumatic ac-
tuator and valve.
Repairs
Devices which are used in safety-instrument-
ed systems must be repaired by the manu-
facturer.
