Common Cause Failure – CCF
The product has been engineered and manufactured according to the basic and well-tried safety
principles of ISO 1389-1 and -2.
Critical failure modes and causes:
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Incomplete reversal - caused by incomplete return of solenoid valve B.
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The pressure applied at port 4 not being dissipated - caused by incomplete return of solenoid
valve A.
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Failure of the safety function - caused by simultaneous incomplete return of both solenoid
valves (A and B).
Common Cause Failures (CCF) are failures of different components, resulting from a single event.
CCF are not to be confused with cascading faults or common mode faults. Common cause
failures can cause loss of the safety function, especially in dual channel circuits where both
channels could fail simultaneously due to a single event. The following measures ensure that
failures due to common causes are avoided:
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Maintain compressed air quality, i.e., filtration, pressure regulation, lubrication.
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Avoid compressor oils that can cause valve seals to swell, soften, or otherwise deteriorate.
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Operate within prescribed temperature limits.
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Install the valve such that the normal stroke travel of the valve elements are perpendicular
to the main direction of machine vibration and/or mechanical shock.
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Observe the permissible values for vibration and shock stress.
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Do not use a test pulse longer than typically 400 to 600 ms and pulse width of 0.4 ms to
0.8 ms.
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Avoid external magnetic fields.
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Do not plug the valve exhaust port.
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The silencer is included in the scope of delivery. Make sure that the silencer is not clogged,
otherwise the silencer must be replaced (see chapter 11 „Spare Parts“).
Diagnostic Coverage
A diagnostic coverage of 99% is achievable through appropriate integration of the safety valve
into the safety control system. The monitoring system must check for the proper change of state
of each valve sensor (S1 & S2) with each change of state of the safety control system outputs to
the valve solenoids (Sol 1 & Sol 2). Detection of a fault by the safety control system must trigger
a shut-off of the safety controller’s outputs to the valve solenoids (Sol 1 & Sol 2). See “Test
Procedure”.
NOTE:
On 5/2 versions, in the event of a fault where the side A valve element is deactuated and
the side B valve element sticks within a very small, specific range of its travel, there is a
possibility of a condition where pressure may not be present in port 2. This fault is detectable
because one position sensor’s output will be high (on) and the other sensor’s output will be low
(off).
WARNING:
On 5/2 versions, in the event of loss of pressure in port 2 during a fault could cause
unexpected movement of a cylinder that is being controlled by the valve.
Fault Modes
Note that normal operation requires that Sol 1 & Sol 2 be energized simultaneously for switching
the safety valve on, and de-energizing both Sol 1 and Sol 2 simultaneously for switching the
safety valve off. Faults that could occur during normal operation:
Sol 1 & Sol 2 energized simultaneously
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S1 ON, S2 OFF
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S1 OFF, S2 ON
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S1 OFF, S2 OFF
Sol 1 & Sol 2 de-energized simultaneously
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S1 ON, S2 OFF
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S1 OFF, S2 ON
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S1 ON, S2 ON
Misuse
Misuse includes:
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Use outdoors
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Bypassing the safety function or diagnostics
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Failing to utilize the onboard sensors to verify valve operation on every cycle – energizing and
de-energizing
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Allowing continued operation of the valve when one or both valve shifted signals (from
position sensors) are not confirmed.
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Use in reverse operation (reversal of supply and exhaust air)
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Operation in low-demand mode per IEC 61508
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Operating at pressures below minimum operating pressure or above maximum operating
pressure.
Personnel qualifications
The work described in this documentation requires basic mechanical, electrical and pneumatic
knowledge, as well as knowledge of the appropriate technical terms. In order to ensure safe use,
these activities may therefore only be carried out by qualified technical personnel or an
instructed person under the direction and supervision of qualified personnel.
Qualified personnel are those who can recognize possible hazards and institute the appropriate
safety measures, due to their professional training, knowledge, and experience, as well as their
understanding of the relevant regulations pertaining to the work to be done. Qualified personnel
must observe the rules relevant to the subject area.
WARNING
Risk of Injury!
Misuse may result in injury or damage.
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The product must be used exclusively as intended.
General safety instructions
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Observe the regulations for accident prevention and environmental protection.
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Observe the safety instructions and regulations of the country in which the product is used.
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Only use the safety valve in perfect working order.
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Persons who do any work on or with the safety valve must not consume any alcohol, drugs,
or pharmaceuticals that may affect their ability to respond.
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Only use accessories and spare parts approved by the manufacturer.
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Comply with the technical data and ambient conditions listed in the product documentation.
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If unsuitable products are installed or used in safety-relevant applications, this may result in
uncontrolled system operating states that may lead to injuries or equipment damage.
Therefore, only use a product in safety-relevant applications if such use is specifically stated
and permitted in the product documentation.
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You may only commission the product if you have determined that the end product (such as
a machine or system) in which the AVENTICS products are installed meets the
country-specific provisions, safety regulations, and standards for the specific application.
Safety instructions related to the product and technology
Personal protective equipment
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Wear appropriate protective clothing during assembly and maintenance. Observe the
applicable occupational safety regulations for the system.
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Always wear ear protectors during operation.
Responsibilities of the system owner
As the owner of a system that will be equipped with an safety valve, you are responsible for
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ensuring intended use,
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ensuring that operating employees receive regular instruction,
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ensuring that the operating conditions are in line with the requirements for the safe use of
the product,
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ensuring that no unauthorized repairs are attempted if there is a malfunction.
Other requirements for the operator:
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Observe the information on assembly and operating conditions listed in the operating
instructions or the data sheet.
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Comply with the further requirements of ISO 13849 (e.g. CCF, DC, PL
r
, software) if you intend
to use the product in higher categories (2 to 4).
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Make sure that the maximum number of switching cycles (B
10d
) within the service life T
M
(typical assumption as per ISO 13849-1 = 20 years) is not exceeded. If the expected number
of switching cycles for a component exceeds the B
10d
value during its period of use, suitable
exchange intervals have to be specified.
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Switch the safety valve at least once a month to ensure its proper function.
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Make sure that the basic and well-tried safety principles in accordance with ISO 13849 for
implementation and operation of the component are complied with.
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Make sure that the permissible positive and negative test pulses for feedback-free operation
of the pneumatic devices are observed (see chapter 12 “Technical Data“).
WARNING
Danger of injury due to stored energy (compressed air) and voltage!
When the system is at a standstill, there is still a danger due to stored energy (compressed air)
and voltage. Dangerous movements are possible e.g. during exhaust.
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Generally avoid storing compressed air.
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Make sure that the relevant system part is not under voltage or pressure pressure before
you install the product or remove it from the system.
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Exhaust the system before working on it.
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Always protect the system against being switched on.
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Remove all other sources of danger in the immediate work area that may result from
stored energy in the system.
Danger of injury by dismantling the safety valve!
Pre-tensioned springs may suddenly be released when dismantling.
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Never dismantle the safety valve.
Injuries if system-specific limits are not complied with!
The operating conditions for the safety valve may deviate from the system operating conditions.
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Always observe the information in the documentation for the superior system.
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Before assembly, contact the system manufacturer or AVENTICS GmbH to clarify any
contradictions or questions.
Danger of burns caused by hot surfaces!
Touching the surfaces of the safety valve and adjacent components during operation could
cause burns.
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Let the relevant system component cool down before working on the safety valve.
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Do not touch the relevant system component during operation.
Risk of injury due to loss of the safety function!
Depending on the application, you must take appropriate measures to ensure the safety function.
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When implementing safety measures against switch-off surges, check whether these
extend the safety valve’s switch-off time.
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Check if the safety valve’s electrical connection cables have to be routed separately.
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In case of high levels of machine vibrations, use appropriate vibration-reducing elements
when mounting the safety valve.
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Avoid overvoltages. These result in solenoid burnout.
Danger due to high sound pressure level!
During operation, the sound pressure level of the device can reach up to 94 dB (A). This may
irreversibly damage the hearing.
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Always wear ear protectors during operation.
AVENTICS
| SV01/SV03/SV05 | R412027221-BAL-001-AA | English
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