This safety manual............................................................................................................................................................................4
Certified SIL 2 Capable.............................................................................................................................................................. 4
User information..........................................................................................................................................................................4
Latest version of technical literature....................................................................................................................................5
Processors and subsystems.......................................................................................................................................................... 6
User application software development requirements............................................................................................. 10
Control of DOUT.............................................................................................................................................................................11
Control of PWMOUT/DOUT........................................................................................................................................................12
SIL capability....................................................................................................................................................................................12
Random capability................................................................................................................................................................... 12
Connection to sensors and actuators ....................................................................................................................................13
Physical location and placement ............................................................................................................................................ 14
Repair and replacement ............................................................................................................................................................. 14
Software/hardware version numbers.....................................................................................................................................14
Danfoss Power Solutions notification ................................................................................................................................... 14
Using the FMEDA results
PFH calculation or PFD
Example application, failure rate analysis........................................................................................................................15
Danfoss | December 2020BC152986482864en-000601 | 3
W
Safety Manual
SC0XX-1XX Safety Controller Family
Introduction
This safety manual
This safety manual provides information necessary to design, implement, verify and maintain a safety
critical function utilizing the PLUS+1® SC0XX-1XX Controller Family. This manual provides necessary
requirements for meeting the IEC 61508 : 2010 Parts 1-7 and IEC 62061:2005+ A1:2012+ A2:2015
functional safety standards:
Warning
Read manual completely before programming your application.
Certified SIL 2 Capable
The SC0XX-1XX Controller Family is certified SIL 2 Capable when deployed with the certified SIL 2
Capable OS that is embedded in their respective SC0XX-1XX HWD files.
The SC0XX-0XX Controller Family is designed for meeting the needs of SIL 2 applications where the OEM
certifies at the machine level. The SC0XX-0XX Controller Family is not certified SIL 2 Capable as a
component regardless of the HWD files with which it is deployed. The table below summarizes this
information (the HWD filenames are representative, but not actual).
In all cases, the OEM/customer is responsible for the safety integrity requirement, implementation, and
validation of their application.
Danfoss | December 2020BC152986482864en-000601 | 5
Connector
Input
conditioning
Power input
Power return
VLDP
Protection and power supplies
Comparator check
V ref
14 V 3 V 5 V
PWM shut-off [1:8]
DOUT shut-off [1:6]
Shut-off check [1:14]
Clock 2
Clock 1
3 V
Reset
Async COM
PWM current feedback [1:8]
PWM control [1:8]
Inputs [1:24]
CAN1
CAN1
CAN2
Sensor power
External
memory
PWM outputs [1:8]
DOUT [1:6]
DOUT status feedback [1:6]
DOUT control [1:6]
Outputs
Power return
Secondary
processor
Voltage
supervisor 2
Voltage
supervisor 1
Primary
processor
3 V
(supply and reference)
Safety Manual
SC0XX-1XX Safety Controller Family
Component description and failure rates
Processors and subsystems
The PLUS+1® SC0XX-1XX Controller has two processors, the primary and the secondary processor, which
communicate asynchronously with each other. The PLUS+1® SC0XX-1XX Controller has six main
subsystems, each of which was analyzed individually. The configuration of a specific controller
deployment is a function of the user application software.
Analyzed subsystems
SubsystemDescription
Common LogicElectrical components and circuitry typically involved with all applications regardless of the
DIN/AIN/FreqINDigital analog and frequency input pins
CrntIn (current)Current input pins
ResINResistance input pins
DOUTDigital output pins
CrntOUT (current)Current output pins
FMEDA analysis
The FMEDA analysis results include the elements shown in the following diagram (components and
inputs/outputs are color coded, blue for the primary processor and red for the secondary processor).
PLUS+1® SC0XX-1XX Controller—Parts included in the FMEDA
Type B component: “Complex” element (using microcontrollers or programmable logic); for details see 7.4.4.1.3 of IEC 61508.
The PLUS+1® SC0XX-1XX Controller is classified as a Type B1 high demand mode component with HFT = 0
per IEC 61508.
The PLUS+1® SC0XX-1XX Controller is certified to provide a 1oo1D architecture in accordance with IEC
61508. This allows the conclusion that a CAT2 architecture can be implemented in accordance with ISO
13849 or ISO 25119. For example this can be accomplished by using the primary processor as main
controller for the Safety Function and the secondary processor as diagnostic element (intelligent watch
dog, TE-Test Equipment) to observe the correct function of the primary processor and to independently
de-energize (safe-state) all corresponding safety-related outputs.
Safety Manual
SC0XX-1XX Safety Controller Family
Component description and failure rates
Detailed analysis, review and documentation for compliance to ISO 13849 or ISO 25119 must be done by
the designer or integrator of the safety related system.
Failure categories description
In order to judge the failure behavior of the PLUS+1® SC0XX-1XX Controller, the following definitions for
the failure of the component apply.
Definitions for failure of the component
Failure category
Fail-Safe StateState where the safety output is de-energized.
Fail SafeState where the safety output is de-energized.
Fail DetectedFailure that is detected by the PLUS+1® SC Controller and causes the
Fail DangerousFailure that deviates the measured input state or the actual output by
Fail Dangerous UndetectedFailure that is dangerous and that is not being diagnosed by automatic
Fail Dangerous DetectedFailure that is dangerous but is detected by automatic diagnostics or is
(2)(3)
Fail High
(2)(3)
Fail Low
No EffectFailure of a component that is part of the safety function but that has no
Annunciation DetectedFailure that does not directly impact safety but does impact the ability to
Annunciation UndetectedFailure that does not directly impact safety but does impact the ability to
λ
SD
λ
SU
λ
DD
λ
DU
λ
D
A
D
A
U
FITFailure In Time (1x10-9 failures per hour)
(1)
The failure categories listed above, expand upon the categories listed in IEC 61508, which are only safe and
dangerous, both detected and undetected. In IEC 61508, the No Effect failures cannot contribute to the failure rate
of the safety function. Therefore, they are not used for the Safe Failure Fraction calculation.
(2)
Depending on the application, a Fail High or a Fail Low failure can either be safe or dangerous and may be
detected or undetected depending on the user software application program.
(3)
Consequently, during a Safety Integrity Level (SIL) verification assessment, the Fail High and Fail Low failure
categories need to be classified as safe or dangerous, and as detected or undetected.
(1)
Definition
output signal to go to the predefined fail safe state.
more than the safety accuracy (2% of span) and that leaves the output
within the active range.
diagnostics or expected user logic.
expected to be detected by user logic.
Failure that causes a safety input signal to go to a value that is clearly
above the normal range and can therefore be reliably detected by the
user application software.
Failure that causes a safety input signal to go to a value that is clearly
below the normal range and can therefore be reliably detected by the
user application software.
effect on the safety function.
detect a future fault (such as a fault in a diagnostic circuit) and that is
detected by internal diagnostics.
detect a future fault (such as a fault in a diagnostic circuit) that is not
detected by internal diagnostics.
Failure rate of all safe detected failures
Failure rate of all safe undetected failures
Failure rate of all dangerous detected failures
Failure rate of all dangerous undetected failures
Failure rate of all dangerous failures, detected and undetected
Failure rate of all annunciation detected failures
Failure rate of all annunciation undetected failures