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2.1.1. Safety Function According to ISO 13849
The CC4 Series valves are designed in accordance with the requirements listed in
ISO 13849-1 and -2. Their "fail-to-safe" safety function is ensured even in case of a
single fault within the valve (e.g., caused by wear, contamination, or similar situations).
The safety function of the CC4 Series valve is to close all the valve's ports in order
to stop motion of the cylinder it is controlling (load holding). The valve can only drive
the cylinder it is controlling forward or backward when the two internal valve elements
are successfully actuated simultaneously (either solenoids 12A & 12B or 14A & 14B).
Otherwise, the CC4 Series valve will close all ports when the valve is de-actuated or
if only one of the two internal valve elements is actuated. A fault in the system where
only one valve actuates when switching on or only one de-actuates when switching off
prevents air from being supplied downstream and simultaneously blocks the exhaust
of any air that is already downstream in the cylinder lines and cylinder. Monitoring of
the two magnetic position sensors by the user's external safety monitoring system
makes it possible to detect these fault situations and to shut off and prevent further
electrical energization of the valve's solenoids and checking to see that the valve's
internal components have returned to the center position, as indicated by the sensors.
The control outputs of the safety system must be designed and constructed to meet the
Category and/or Performance Level requirements of the safety system, as determined
by the risk assessment of the machine. Normally, the output to the solenoids is a dual-
channel output from a safety relay or safety PLC.
Leakage in a safe cylinder stop/load holding application has the potential to create
unexpected motion regardless of whether the leakage occurs in the valve, hoses,
connections or the cylinder. The CC4 series valves are equipped with valve position
sensors for external monitoring to meet diagnostic coverage requirements. However,
position sensing does not detect leakage. The CC4 series valves are designed to
have redundant valve elements that are interconnected in such a manner that
any single point of leakage within the valve will not cause unexpected movement.
Therefore, periodic leakage testing of the system may be necessary depending on
the risk assessment specific to the machine or application. If leakage is discovered,
measures should be taken to eliminate the leak.
WARNING: Continued operation of the system without periodic leakage inspections
can lead to unexpected movement.
2.1.2. Common Cause Failure – CCF
The product has been engineered and manufactured according to the fundamental
and proven safety principles of ISO 13849-1 and -2.
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.
• Maintain compressed air quality, i.e., filtration, pressure regulation, lubrication.
• Avoid compressor oils that can cause valve seals to swell, soften, or otherwise
deteriorate.
• Conduct leakage tests of the load holding system, including the connecting lines,
fittings, and actuator seals, on commissioning and periodically during use.
• Operate within prescribed temperature limits.
• 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.
• Avoid external magnetic fields.
• Do not plug the valve exhaust port.
• Use only high-flow, non-clogging silencers, with similar or higher specifications as
ROSS
silencers.
®
2.1.3. Diagnostic Coverage
A diagnostic coverage of 99% is achievable through appropriate integration of the
CC4 Series valve into the safety control system. The monitoring system must check
for the proper change of state of each valve sensor (Sensor A & Sensor B) with each
change of state of the safety control system outputs to the valve solenoids (Solenoids
12A & 12B or Solenoids 14A & 14B). Detection of a fault by the safety control system
must trigger a shut-off of the safety controller's outputs to all of the valve's solenoids
(12A, 12B, 14A, & 14B), see section 8.
2.1.4. Fault Modes
Note that normal operation requires that solenoids 14A & 14B be energized simulta-
neously for switching the CC4 Series valve on in order to drive the cylinder forward
(port 4 pressurized and port 2 exhausted), or that solenoids 12A & 12B be energized
simultaneously in order to drive the cylinder backward (port 2 pressurized and port 4
exhausted). De-energizing all of the valve's solenoids simultaneously switches the
CC4 Series valve off and traps pressure on ports 2 & 4 in order to stop the cylinder
(load-holding).
Faults that could occur during normal operation:
Solenoids 12A & 12B energized simultaneously
Sensor A ON, Sensor B OFF
Sensor A OFF, Sensor B ON
Sensor A ON, Sensor B ON
4
Solenoids 14A & 14B energized simultaneously
Sensor A ON, Sensor B OFF
Sensor A OFF, Sensor B ON
Sensor A ON, Sensor B ON
All solenoids de-energized simultaneously
Sensor A ON, Sensor B Off
Sensor A OFF, Sensor B ON
Sensor A OFF, Sensor B OFF
2.1.5. Improper Use
Risk of Injury!
Misuse may result in injury or damage.
f The product must be used exclusively as intended.
The following applications are prohibited:
•
Use outdoors
•
Use in non-industrial applications/residential areas
•
Use outside of the product limits defined in the technical data
•
Unauthorized modifications
•
Use as a press safety valve to control a clutch or brake
•
Bypassing the safety function or diagnostics
•
Allowing continued operation of the valve when one or both valve shifted signals
(from the onboard mid-position sensors) are not confirmed.
•
Use in reverse operation (reversal of supply and exhaust air)
•
Operation in low-demand mode per IEC 61508
•
Operation in hazardous locations
ROSS CONTROLS is not liable for any damages resulting from improper use.
The user alone bears the risks of improper use of the product.
2.2. Responsibilities of the System Owner
•
Observe the information on assembly and operating conditions listed in the
operating instructions or the data sheet.
•
Comply with the further requirements of ISO 13849 (e.g., CCF, DC, PLr, software)
if you intend to use the product in higher categories (2, 3, or 4).
•
Make sure that the maximum number of switching cycles (B
life T
is not exceeded. If the expected number of switching cycles for a component
m
exceeds the B
value during its period of use, suitable replacement intervals
10D
have to be specified.
•
Switch the valve at least once a month to ensure its proper operation.
•
Make sure that the fundamental and proven safety principles in accordance
with ISO 13849 for implementation and operation of the component are
complied with.
•
Make sure that the permissible switch-on and switch-off pulses for feedback-free
operation of the pneumatic devices are observed.
•
If you operate the CC4 Series valve together with an electric two-hand control, it
must comply with the EN 574 standard. Selection and installation of this two-hand
control must take place in accordance with the manufacturer's specifications.
2.3. Safety Instructions
•
When implementing surge suppression measures, be sure to check whether or
not this extends the valve shut off response time which could extend the machine
stopping time.
•
In case of high levels of machine vibration, use appropriate vibration-reducing
elements when installing the valve.
•
Supply the proper voltage as overvoltage situations can result in solenoid burnout.
•
Make sure that the silencer's flow capacity is not restricted as this could affect
system performance.
•
If required, replace the silencer exclusively with a corresponding ROSS model.
3. Product Identification
Date of manufacture and site of manufacture are permanently stamped:
Manufacturing site
Site abbreviation
ROSS CONTROLS USA
(L)
ROSS EUROPA
(G)
ROSS UK
(RB)
ROSS ASIA
(J)
ROSS SOUTH AMERICA
(B)
ROSS CONTROLS CHINA
(C)
ROSS CONTROLS INDIA
(RCI)
See back page for ROSS addresses.
Product label identification & product key identification example, see page 2.
CC4 Series Operating Instructions
WARNING
) within the service
10D
Valve printing
(example May 2016)
(5 16 L)
(5 16 G)
(5 16 RB)
(5 16 J)
(5 16 B)
(5 16 C)
(5 16 RCI)
www.rosscontrols.com
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