Transmitter PASCAL Ci4
Type series CI4xxx
LABOM Mess- und Regeltechnik GmbH Im Gewerbepark 13 27798 Hude Germany
SA_001_2019-07_10.00
Hotline: +49 4408 804-444 Fax: +49 4408 804-100 e-mail: sales@labom.com www.labom.com
SIL Instructions
Safety Integrity Level
SIL2
Operating Modes
Low and continuous demand mode
Achitecture
1oo1
Device Type
B
Hardware Fault Tolerance
HFT
0
Safe Failure Fraction
SFF
95,29 %
Failure rate for safe detected failures
SD
1,81∙10
-7
1/h
Failure rate for safe undetected failures
SU
3,11∙10
-7
1/h
Failure rate for dangerous detected
failures
DD
3,42∙10
-7
1/h
Failure rate for dangerous undetected
failures
DU
4,13∙10
-8
1/h
Probability of a dangerous undetected failure per hour
PFH
4,13∙10
-8
1/h
Mean time between failures =
Mean time to failure
MTBF
=
MTTF
130 a
Mean time to dangerous failure
MTTFd
2764 a
Inspection Interval
T1
1 year
2 years
3 years
5 years
Probability of a dangerous undetected
failure on demand
PFD
1,84∙10
-4
3,64∙10
-4
5,45∙10
-4
9,06∙10
-4
Safety-related parameters
for MTTR = MRT = 8 h
Page 1/4
The safe function can only be guaranteed if the option "Functional safety according to IEC/EN 61508" has been chosen for
the device. These devices are marked as shown on the right.
SIL marking on the unit.
1 General Information
These SIL Instructions contain information and instructions for using the device as part of
your protection system according to IEC/EN 61508. In addition to these instructions,
please take all relevant legal requirements, applicable standards as well as the additional
technical specifications on the accompanying data sheet into account (see
www.labom.com).
1.1 Safe Function
The safe function of the device according to IEC/EN 61508 is the 4…20 mA current signal.
1.2 Validity
2 Technical Data
The following technical data applies to the safe function of the device.
2.1 Accuracy
Assured accuracy in safe mode: 1%
For devices with diaphragm seal take the error of the diaphragm seal into account as well.
For devices with ATC-option the accuracy for devices without ATC-option applies only.
Please observe that for devices with operating software for level applications inaccurate
level parameters directly affect the accuracy of the level calculation. E. g. the less accurate
the density is set, the more the calculated level deviates from the actual level.
2.2 Reaction Times
In the event of a request: 220 ms
In the event of fault detection: 100 ms
Note that any set damping value can extend the reaction time in the event of a request.
Additional elements in the process connection, such as capillaries, can extend the reaction
time in the event of sudden pressure changes in the process.
2.3 Start-up Behaviour
A safe state is also guaranteed during initialisation or a phase of low voltage. After connecting the supply voltage, a current of < 3.6 mA (alarm current) is issued at the current
output. Following completion of initialisation, after about 5 seconds, the current output
jumps to a current proportional to the applied pressure or approaches the correct current
according to the set damping value.
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2.4 Troubleshooting
In the event of a critical device malfunction, an alarm current of < 3.6 mA or > 21 mA is
permanently issued at the output.
The alarm current can be deactivated by a manual restart only.
3 Requirements for the Operator
The operator has to consider the following requirements to ensure that the safe function is
not jeopardised.
3.1 Unsafe Operating Conditions
Avoid the following functions while using the devices as part of a protection system:
HART multi-drop operation in fixed current mode
Pressure or current simulation
Adjustment of the current output
Communicating with the device via HART or the display module does not affect the safe
function, providing no parameters are changed that affect the current signal.
The value at the current output is no longer proportional to the pressure when using the
table function, for example, to map the tank shape when measuring the level. A fault in the
support points of the table leads to a faulty signal current. There is a linear interpolation of
the measurement between these support points. This reduces the accuracy between the
support points.
When using the table function in SIL application, the operator should therefore take appropriate measures to ensure the correctness and sufficient accuracy of the table.
3.1.1 Ci4 LEVEL
For devices with operating software for level applications please pay attention to the following points:
Set the height offset first and then scale the current output (parameters „value for 4 mA“
and „value for 20 mA“). This is because the scaling of the current output is based on the
height offset.
Ensure that the hydrostatic pressure of a completely filled tank does not exceed the nomi-
nal range of the device.
Ensure that the value for 4 mA does not represent a level that lies below the process con-
nection of the device.
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3.2 Requirements for Safe Operation
Avoid unsafe operating conditions (see 3.1).
Ensure compatibility of wetted materials with process media and cleaning agents.
Avoid environmental conditions that exceed the data sheet limits.
Avoid a pressure load that exceeds the permissible pressure limits as per the data sheet.
Monitor both alarm states (< 3.6 mA or > 21 mA) regardless of the alarm function setting.
Avoid an excessive supply voltage above 30 V.
3.3 Regular Inspections
Hazardous undetected faults during operation can be detected with a high level of certainty during regular inspections. The operator can define the inspection interval depending on
the PFD value required.
Not only the device but the complete measuring chain should be tested during inspection.
It is the responsibility of the plant operator to determine an adequate test of the safety
function.
The following inspection procedure is recommended for the device to achieve a high fault
detection.
Set the current simulation to a value of ≤ 3.6 mA and check whether the current
output reaches this value
Set the current simulation to a value of > 21 mA and check whether the current out-
put reaches this value
Apply one or more pressure values - depending on the safety-related pressure
range - and check whether the current output corresponds to the applied pressure
Visual monitoring of damage
SA_001_2019-07_10.00 Transmitter PASCAL Ci4 Page 4/4
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