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1Description
Passive isolator, one and two channel
MACX MCR-SL-(2)I-(2)I-HV-ILP
(-SP)
© PHOENIX CONTACT
Data sheet
The single- or dual-channel input loop powered 2-way isola-
tor with increased isolation voltage and plug-in connection
technology is used for the electrical isolation and filtering of
analog signals.
The device allows operation on active sensor technology
with a supply voltage of 6V...30VDC.
The device is powered via the current loop of the sensor.
Therefore, no additional power supply is necessary.
Input signal = output signal: 0(4)mA...20mA
The measurement signal is transferred 1:1.
Features
– 2-wire passive isolators for electrical isolation and filter-
ing of standard analog signals.
– Supplied by an input loop
–2.9V voltage drop
–Up to SIL3 according to IEC/EN61508
– 2-way electrical isolation
– Plug-in connection terminal blocks, either screw or
spring-cage connection technology (Push-in technolo-
gy)
– Installation in Ex zone 2 permitted
– Housing width of 12.5mm
Make sure you always use the latest documentation.
It can be downloaded from the product at phoenixcontact.net/products.
This document is valid for the products listed in the “Ordering data”.
106894_en_01 2015-12-07
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 2
2Table of contents
1 Description .............................................................................................................................. 1
2 Table of contents..................................................................................................................... 2
3 Ordering data .......................................................................................................................... 3
4 Technical data ......................................................................................................................... 3
5 Safety notes............................................................................................................................. 5
5.1 Installation notes ................................................................................................................. 5
5.2 Installation in the Ex area (zone 2)............................................................................................ 5
5.3 UL Notes ........................................................................................................................... 5
6 Installation ............................................................................................................................... 6
6.1 Connection notes ................................................................................................................ 6
6.2 Electrostatic discharge.......................................................................................................... 6
6.3 Structure ........................................................................................................................... 6
6.4 Basic circuit diagram with connection terminal blocks ................................................................... 7
6.5 Power supply...................................................................................................................... 7
6.6 Dimensions ........................................................................................................................ 7
6.7 Assembly........................................................................................................................... 8
6.8 Connecting the cables .......................................................................................................... 8
6.9 Startup.............................................................................................................................. 8
7 Method of operation................................................................................................................. 9
8 Safety-related applications ...................................................................................................... 9
8.1 Safety function.................................................................................................................... 9
8.2 Operating mode .................................................................................................................. 9
8.3 Relevant standards .............................................................................................................. 9
8.4 Safety integrity requirements ................................................................................................ 10
8.5 Conditions ....................................................................................................................... 10
8.6 Installation and startup ........................................................................................................ 10
8.7 Notes on operation............................................................................................................. 11
8.8 Recurring checks............................................................................................................... 11
8.9 Repair............................................................................................................................. 11
8.10 Standards........................................................................................................................ 12
8.11 Abbreviations ................................................................................................................... 12
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 3
Description Type Order No. Pcs./Pkt.
Single-channel input loop-powered 2-way isolator with increased cut-off
voltage and plug-in connection technology for the electrical isolation of an-
alog signals. Input signal = output signal: 0(4) mA ... 20 mA. Screw connec-
tion technology.
MACX MCR-SL-I-I-HV-ILP 2907704 1
Single-channel input loop-powered 2-way isolator with increased cut-off
voltage and plug-in connection technology for the electrical isolation of an-
alog signals. Input signal = output signal: 0(4) mA ... 20 mA. Push-in con-
nection technology.
MACX MCR-SL-I-I-HV-ILP-SP 2907705 1
Two-channel input loop-powered 2-way isolator with increased cut-off volt-
age and plug-in connection technology for the electrical isolation of analog
signals. Input signal = output signal: 0(4) mA ... 20 mA. Screw connection
technology
MACX MCR-SL-2I-2I-HV-ILP 2907706 1
Two-channel input loop-powered 2-way isolator with increased cut-off volt-
age and plug-in connection technology for the electrical isolation of analog
signals. Input signal = output signal: 0(4) mA ... 20 mA. Push-in connection
technology.
MACX MCR-SL-2I-2I-HV-ILP-SP 2907707 1
3Ordering data
4 Technical data
Input data
Description of the input Current input
Configurable/programmable no
Max. voltage input signal < 30.5 V
Current input signal 0 mA ... 20 mA
4 mA ... 20 mA
Input voltage limitation 30.5 V
Voltage dissipation 2.9 V (I = 20 mA)
Step response (10-90%) 5 ms (500 Ω load)
Output
Output description Current output
Configurable/programmable no
Output signal maximum voltage 27.5 V
Current output signal 0 mA ... 20 mA
4 mA ... 20 mA
Transmission Behavior 1:1 to input signal
Load/output load current output ≤ 1375 Ω (I = 20 mA)
Residual ripple < 10 mVrms (500 Ω load)
Supply
Supply voltage range no separate supply voltage necessary
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 4
General data
Maximum transmission error ≤ 0.1 % (of final value)
Maximum temperature coefficient ≤ 0.002 %/K (of measured value / 100 Ω load)
Degree of protection IP20
Flammability rating according to UL 94 V0
Overvoltage category II
Pollution degree 2
Dimensions W/H/D 12.5 mm / 99 mm / 114.5 mm ( MACX MCR-SL-I-I-HV-ILP )
12.5 mm / 99 mm / 114.5 mm ( MACX MCR-SL-I-I-HV-ILP-SP )
Type of housing PA 66 green
Connection data Screw connection Push-in connection
Conductor cross section, solid 0.2 mm² ... 2.5 mm² 0.2 mm² ... 1.5 mm²
Conductor cross section, flexible 0.2 mm² ... 2.5 mm² 0.2 mm² ... 1.5 mm²
Conductor cross section AWG 24 ... 14 24 ... 16
Stripping length 7 mm 8 mm
Tightening torque 0.5 Nm ... 0.6 Nm
Diameter Test socket in the connector 2.3 mm 2.3 mm
Ambient conditions
Ambient temperature (operation) -40 °C ... 85 °C
Ambient temperature (storage/transport) -40 °C ... 85 °C
Permissible humidity (operation) 5 % ... 95 % (non-condensing)
Maximum altitude for use above sea level < 2000 m
Electrical isolation
Input/output/power supply
Rated insulation voltage (overvoltage category II; pollution degree 2, safe
isolation as per EN 61010-1)
50 Hz, 1 min., test voltage
600 Vrms
5 kV
Conformance with EMC directive 2004/108/EC and for low-voltage directive 2006/95/EC
Noise immunity according to EN 61326-1
Conformance / approvals
ATEX II 3 G Ex nA IIC T4 Gc X
UL, USA / Canada UL 61010 Listed
Class I, Div. 2, Groups A, B, C, D T4
Class I, Zone 2, Group IIC T4
Functional Safety in accordance with IEC 61508 ( 968/FSP1200.00/15 ) to SIL 3
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 5
5Safety notes
5.1 Installation notes
•The category 3 device is suitable for installation in the
zone 2 potentially explosive area. It fulfills the require-
ments of EN60079-0:2012+A11:2013 and EN60079-
15:2010.
•Installation, operation, and maintenance may only be
carried out by qualified electricians. Follow the installa-
tion instructions as described. When installing and op-
erating the device, the applicable regulations and safety
directives (including national safety directives), as well
as generally approved technical regulations, must be
observed. The safety data is provided in this package
slip and on the certificates (conformity assessment, ad-
ditional approvals where applicable).
•The device must not be opened or modified. Do not re-
pair the device yourself, replace it with an equivalent de-
vice. Repairs may only be carried out by the
manufacturer. The manufacturer is not liable for dam-
age resulting from violation.
•The IP20 protection (IEC 60529/EN 60529) of the de-
vice is intended for use in a clean and dry environment.
The device must not be subject to mechanical strain
and/or thermal loads, which exceed the limits de-
scribed.
•The device must be stopped if it is damaged, has been
subjected to an impermissible load, stored incorrectly,
or if it malfunctions.
•The device is not designed for use in potentially dust-
explosive atmospheres. If dust is present, installation
must take place in a suitable and approved housing (at
least IP54) that meets the requirements of EN 60079-
31. The specified surface temperature of the housing
must be observed.
•The device complies with the EMC regulations for in-
dustrial areas (EMC classA). When using the device in
residential areas, it may cause radio interference.
5.2 Installation in the Ex area (zone 2)
•Observe the specified conditions for use in potentially
explosive areas! Install the device in a suitable ap-
proved housing (with a minimum of IP54 protection) that
meets the requirements of EN 60079-15. Observe the
requirements of EN 60079-14.
•Only devices which are designed for operation in Ex
zone 2 and are suitable for the conditions at the installa-
tion location may be connected to the circuits in the Ex
zone.
•In potentially explosive areas, terminals may only be
snapped onto or off the DIN rail connector and wires
may only be connected or disconnected when the pow-
er is switched off.
•The device must be stopped and immediately removed
from the Ex area if it is damaged, was subject to an im-
permissible load, stored incorrectly or if it malfunctions.
5.3 UL Notes
PROCESS CONTROL EQUIPMENT FOR HAZARDOUS
LOCATIONS 31ZN
1 Suitable for use in class 1, division 2, groups A, B, C and
D hazardous locations, or nonhazardous locations only.
2 WARNING - EXPLOSION HAZARD: Do not disconnect
equipment while the circuit is live or unless the area is
known to be free of ignitable concentrations.
3 WARNING - EXPLOSION HAZARD: Substitution of any
components may impair suitability for Class I, Division
2.
m
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 6
6 Installation
6.1 Connection notes
•Provide a switch/circuit breaker close to the device,
which is labeled as the disconnecting device for this de-
vice.
•Provide overcurrent protection (I ≤ 16 A) within the in-
stallation.
•To protect the device against mechanical or electrical
damage, install it in a suitable housing with appropriate
degree of protection as per IEC60529.
•During installation, servicing, and maintenance work,
disconnect the device from all effective power sources,
provided you are not dealing with SELV or PELV cir-
cuits.
•If the device is not used as described in the documenta-
tion, the intended protection can be negatively affected.
•Thanks to its housing, the device has basic insulation to
the neighboring devices, for 300 Veff. If several devices
are installed next to each other, this has to be taken into
account, and additional insulation has to be installed if
necessary! If the neighboring device is equipped with
basic insulation, no additional insulation is necessary.
•The voltages present at the input and output are extra-
low voltages (ELV). Depending on the application, dan-
gerous voltage (>30V) to ground could occur at the in-
put and output. The supply voltage could be a
dangerous voltage, depending on the application. All
connections are safely electrically isolated from each
other.
6.2 Electrostatic discharge
6.3 Structure
Figure 1 Structure
1COMBICON plug-in, screw, or push-in connection ter-
minal with integrated test socket
2Snap-on foot for DIN rail mounting
WARNING: Electrical danger due to im-
proper installation
Observe the connection notes for safe instal-
lation in accordance with EN/UL61010-1:
NOTE: Electrostatic discharge
The device contains components that can be
damaged or destroyed by electrostatic dis-
charge. When handling the device, observe
the necessary safety precautions against
electrostatic discharge (ESD) according to
EN 61340-5-1 and IEC 61340-5-1.
MACX MCR-SL-I-I-HV-ILP-SP
3.1 3.2
4.1 4.2
3.1 3.2
Flachsmarktstraße
32825 Blomberg, Germany
MACX MCR-SL-I-I-HV-ILP-SP
Ord.-No.: 2907705
WWW.phoenixcontakt.com
Input loop powered signal conditioner
-+
active 4-
Wire
S
U
IN
Input
0/4 ... 20mA IN = OUT
Output
0/4 ... 20mA IN = OUT
Max. Input Voltage
30VDC
T
amb
-40°...+85°C/-40°...+185°F
+-
passive
OUT
CH1
3.1 3.2
4.2
4.1
active
passive
Voltage drop
2,9VDC at 20mA
see manual
WARNING
DO NOT SEPARATEWHEN ENERGIZED
AND INSTALLED IN ZONE 2
3.1 3.2
MACX MCR-SL-I-I-HV-ILP
3.1 3.2
4.1 4.2
Flachsmarktstraße
32825 Blomberg, Germany
MACX MCR-SL-I-I-HV-ILP
Ord.-No.: 2907704
WWW.phoenixcontakt.com
Input loop powered signal conditioner
-+
active 4-
Wire
S
U
IN
Input
0/4 ... 20mA IN = OUT
Output
0/4 ... 20mA IN = OUT
Max. Input Voltage
30VDC
T
amb
-40°...+85°C/-40°...+185°F
+-
passive
OUT
CH1
3.1 3.2
4.2
4.1
active
passive
Voltage drop
2,9VDC at 20mA
see manual
WARNING
DO NOT SEPARATEWHEN ENERGIZED
AND INSTALLED IN ZONE 2
2
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MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 7
6.4 Basic circuit diagram with connection terminal
blocks
Figure 2 Single-channel
Figure 3 Two-channel
6.5 Power supply
An ME 6,2 TBUS-2 DIN rail connector (Order No. 2869728)
is used to supply active devices. A DIN rail connector is not
required to operate this passive device.
This device can be snapped onto a DIN rail connector – an
electrically conductive connection is not established. This
means that you do not need to disconnect an existing DIN
rail connector element connection.
6.6 Dimensions
Figure 4 Dimensions
PLC / DCS
passive CH1
3.2
3.1
-
+
Sensor / Field
4-
Wire
+
-
active
4.2
4.1
US
IN OUT
Zone 2
active
4.2
4.1
3.2
3.1
passive
99
116 (SP)
112,5
12,5 7
114,5
AWG 24-16
mm MCR-...-SP o,2-1,5 mmz
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 8
6.7 Assembly
Figure 5 Mounting and removing
The device can be snapped onto all 35 mm DIN rails accord-
ing to EN 60715.
An ME 6,2 TBUS-2 DIN rail connector (Order No. 2869728)
is used to supply active devices. A DIN rail connector is not
required to operate this passive device.
This device can be snapped onto a DIN rail connector – an
electrically conductive connection is not established. This
means that you do not need to disconnect an existing DIN
rail connector element connection.
6.8 Connecting the cables
Screw connection:
Figure 6 Screw connection
•Strip the wire by approximately 7mm and crimp ferrules
to the end of the wires.
•Insert the wire into the corresponding connection termi-
nal block.
•Use a screwdriver to tighten the screw in the opening
above the connection terminal block.
Tightening torque: 0.6Nm
Push-in connection:
Figure 7 Push-in connection
•Strip the wire by approximately 8mm and crimp ferrules
to the end of the wires.
•Insert the wire into the corresponding connection termi-
nal block.
•Push in the pushbutton with a screwdriver to release.
6.9 Startup
•Before startup, check that the device is operating and
wired correctly.
B
AC
DE
0,5-0,6 Nm
5-7 lb In
7 mm
AWG 24-14
0,2-2,5 mm
2
MACX MCR-...
A
B
7H
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 9
7 Method of operation
The passive isolator draws the power required for isolation
from the input signal.
When using passive isolators, make sure that the current
sourcing voltage of the measuring transducer UB is sufficient
to drive the maximum current of 20mA via the passive iso-
lator with a voltage drop UV = 2.9V and load RB.
This means:
UB ≥ UE = 2.9V + 20mA x RB
8 Safety-related applications
The following notes apply for the devices:
The devices listed above are certified in compliance with
DINEN61508-1:2010 and DINEN61508-2:2010. Test cer-
tificate: 968/FSP1200.00/15
The devices are TÜV-certified.
8.1 Safety function
The defined safety function for the devices applies for the
input signal range of 4...20mA.
The device transfers a measuring signal of 4...20mA –
electrically isolated – into an output signal of 4...20mA with
a tolerance of 2%. The input signals are transferred in a lin-
ear 1:1 ratio.
The fault signal is defined for the ranges between <3.6mA
and >21mA.
The analog output signal has to be evaluated using a down-
stream logic unit.
In the case of a two-channel, redundant application (1oo2),
you must compare the values and establish a safe state
when exceeding a certain tolerance.
8.2 Operating mode
Operating mode in accordance with EN61508: "low require-
ment rate" or "high requirement rate" (six requirements per
minute maximum)
8.3 Relevant standards
The device can be used in safety-related applications up to
SIL3 (systematic suitability SC3). The standards which are
relevant to the intended purpose, suchas EN61508 and
EN62061, must be applied.
I
M MCR-SL-ACX (2)I-(2)I-ILP(-SP)
U
E
U= V2.9
V
I
I
I
R
B
U
B
Designation Order No.
MACX MCR-I-I-HV-ILP 2907704
MACX MCR-I-I-HV-ILP-SP 2907705
MACX MCR-2I-2I-HV-ILP 2907706
MACX MCR-2I-2I-HV-ILP-SP 2907707
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 10
8.4 Safety integrity requirements
8.4.1 Error rates
– Type A device (according to EN61508-2)
– Safety integrity level (SIL) 3
–Operating mode 4...20mA
– MTTFD 221a
– MTTR 72h
–Ambient temperature40°C
8.4.2 Load 700
Failure rate in FIT
The MTBF is 1,106 years.
PFH/PFD values
8.4.3 Load >700
Failure rate in FIT
The MTBF is 1,106 years.
PFH/PFD values
8.5 Conditions
– The failure rates of the components used remain con-
stant throughout the period of use.
– The propagation of errors by the device in the system is
not taken into consideration.
– The repair time (replacement) should be eight hours.
– The failure rates of the external power supply are not
taken into consideration.
– The average temperature at which the device is to be
used is+40°C.
– The specified error rates are based on an ambient tem-
perature of+40°C.
8.6 Installation and startup
During installation, observe the instructions in the package
slip:
The package slip is supplied with the device. It can also be
downloaded at: phoenixcontact.net/products.
Lockable housing with IP54 protection is recommended for
the installation of the devices.
•Connect the device according to the installation notes.
•Make sure that the connected sensor and measuring
transducer correspond to the intended configuration.
•Check that the device operates correctly with the mea-
suring transducer and sensor connected.
•A calibrated sensor simulator and a calibrated digital
multimeter may be required in order to check the device
with the measuring transducer connected.
•Start up the safety circuit and check that it operates cor-
rectly.
Total SDSD DU DD SFF DCD
103,2 101.7 1.5 0 1.5 0 98.6% 0 %
T [PROOF] 1 year 2 years 3 years
PFD1oo1 6,6*10-6 1,3*10-5 2*10-5
PFH1oo1 1,5*10-9 1,5*10-9 1,5*10-9
PFD1oo2 6,6*10-7 1,3*10-6 2*10-6
PFH1oo2 1,5*10-10 1,5*10-10 1,5*10-10
Total SDSD DU DD SFF DCD
103,294.2909091.3%0 %
T [PROOF] 1 year 2 years 3 years
PFD1oo1 4*10-5 7.9*10-5 1.2*10-4
PFH1oo1 9*10-9 9*10-9 9*10-9
PFD1oo2 4*10-6 7.9*10-6 1.2* 10-5
PFH1oo2 9*10-10 9*10-10 9*10-10
NOTE:Installation, operation, and mainte-
nance may only be carried out by profession-
als.
Designation MNR No.
PACKB.MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP) 9071547
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 PHOENIX CONTACT 11
8.7 Notes on operation
The output signal of the passive isolator in normal, uninter-
rupted mode is within the range of 3.6...21mA. If a fault or
error occurs during operation, the connected safety-related
controller establishes that a measured value is outside of
normal operation and initiates appropriate measures. As it
cannot be established whether the error was caused by the
passive isolator or by the devices connected upstream of
the passive isolator, you must check the entire safety loop
from the sensor to the output of the passive isolator.
After being switched off and on again, the required voltages
are established in the device. Signal transmission is then
performed without further action.
8.8 Recurring checks
The function of the entire safety loop must be checked reg-
ularly according to IEC/EN61508 and IEC/EN61511.
The intervals for checking are specified by the intervals of
each individual device within the safety loop.
It is the operator's responsibility to select the type of checks
and the checking intervals in the specified time period.
Checking must be carried out in such a way that the correct
function of the safety equipment in conjunction with all com-
ponents can be verified.
Possible procedure for recurring checks for discover-
ing dangerous and undetected device failures
A calibrated simulator (0/4...20mA current) or a sensor
simulator and one or ideally two calibrated digital multime-
ters are required in order to check the devices.
1. Take appropriate steps to prevent incorrect use.
2. Disconnect the safety circuit from further processing.
3. Connect the current simulator to the input of the repeat-
er power supply/signal conditioner, or the sensor simu-
lator to the input of the measuring transducer.
4. Connect the digital multimeters to the input and output
of the repeater power supply/signal conditioner.
5. At the input of the device, set a signal in the range from
4...20mA or at the input of the connected measuring
transducer, set a suitable signal with the sensor simula-
tor.
6. Measure the current in the repeater power supply/signal
conditioner. The output must be set to the same value.
7. Setting ≤ 3.6mA or > 21mA verifies that the subse-
quent processing can detect signals that are out of
range and evaluate them accordingly. If the output value
deviates from the input value by more than 3 times the
specified class accuracy rating, the device should be
checked. In the event of an error, the device should be
replaced with an equivalent device.
8. Restore the safety circuit to full functionality.
9. Resume normal operation.
8.9 Repair
The devices have a long service life, are protected against
malfunctions, and are maintenance-free.
However, if a device should fail, send it back to Phoenix
Contact immediately. The type of malfunction and possible
cause must also be stated.
Please use the original packaging or other suitable safe
packaging when sending devices back for repairs or recali-
bration.
Phoenix Contact GmbH & Co. KG
Abteilung Service und Reparatur
Flachsmarktstr. 8
32825 Blomberg
GERMANY
MACX MCR-SL-(2)I-(2)I-HV-ILP(-SP)
106894_en_01 12
PHOENIX CONTACT GmbH & Co. KG • 32823 Blomberg • Germany
phoenixcontact.com
8.10 Standards
The devices are developed and tested according to the following standards:
8.11 Abbreviations
IEC/EN61508-1 Functional Safety of electrical/electronic/programmable electronic safety-related systems - Part1:
General requirements
IEC/EN61508-2 Functional Safety of electrical/electronic/programmable electronic safety-related systems - Part2:
Requirements for electrical/electronic/programmable electronic safety-related systems
IEC/EN61326-1 Electrical equipment for measurement, control and laboratory use - EMC requirements
IEC/EN61326-3-2 Electrical equipment for measurement, control and laboratory use - EMC requirements - Part 3-2:
Immunity requirements for safety-related systems and for equipment intended to perform safety-re-
lated functions (Functional Safety) - Industrial applications with specified electromagnetic environ-
ment
IEC/EN61511 Functional safety - Safety instrumented systems for the process industry sector
Abbreviation Meaning
DCDDiagnostic coverage of dangerous failures Diagnostic coverage of dangerous failures:
DCD = DD/(DU + DD)
DCSDiagnostic coverage of safe failures Diagnostic coverage of safe failures:
DCS = SD/(SU + SD)
FIT Failure in time 1 FIT = 1 failure/109h
HFT Hardware fault tolerance Hardware fault tolerance: ability of a function unit to continue with
the execution of a demanded function despite existing faults or
deviations
DRate of dangerous failures Proportion of dangerous failures per hour
DD Rate of dangerous detected failures Proportion of detected dangerous failures per hour
DU Rate of dangerous undetected failures Proportion of undetected dangerous failures per hour
SRate of safe failures Proportion of safe failures per hour
SD Rate of safe detectable failures Proportion of detectable safe failures per hour
SU Rate of safe undetectable failures Proportion of undetectable safe failures per hour
MTBF Mean time between failures Mean time between consecutive failures
PFDavg Average probability of failure on demand Average probability of dangerous failure on demand of a safety
function
PFH Probability of a dangerous failure per hour Probability of failure per hour for the safety function
PL Performance level The performance level indicates the capability of safety-related
parts of a control system to carry out a safety function in foresee-
able conditions (PL: a, b, c, d, e)
SFF Safe failure fraction Proportion of safe failures: proportion of failures without the po-
tential to set the safety-related system to a dangerous or imper-
missible function state
SIL Safety integrity level International standard IEC61508 defines four discrete safety in-
tegrity levels (SIL 1 to 4). Each level corresponds to a probability
range for the failure of a safety function. The higher the safety in-
tegrity level of safety-related systems, the lower the probability
that the demanded safety functions will not be performed.