Safe Air Entry Assembly with M35 Series Safe Exhaust Valve Safety Category. 4 PL e, Externally Monitored

Product Overview

The ROSS Controls is a pre-engineered Safe Air Entry Assembly built around the M35 Series Control Reliable Safe Exhaust Double Valve, delivering Safety Category 4, Performance Level e (PL e), SIL 3 performance for the most demanding externally monitored pneumatic safety applications. The M35 Series uses ROSS's proven SERPAR crossflow technology with redundant, 3/2 normally closed, dual poppet construction - two independent valve elements operating synchronously - to provide a control-reliable safe exhaust function that shuts off and exhausts even when one element faults.

Each M35 valve element has one solenoid, and both solenoids operate simultaneously during machine cycles. Integrated pressure sensors on both valve elements allow the external safety controller to verify correct valve state on every actuation, providing the dynamic external monitoring required to achieve Category 4 under ISO 13849-1:2015. The optional EEZ-ON Soft-Start module, available on 1/2 inch port size configurations, allows gradual downstream pressure buildup to approximately 50% of inlet before fully opening, protecting personnel and equipment from sudden pressure surges.

Assembly components include the Classic or Modular L-O-X Lockout valve for OSHA- and ANSI-compliant energy isolation, MD Series filter/regulator/lubricator with metal bowls or polycarbonate bowls depending on the lockout type, and the M35 double valve with LED indicators, built-in silencer, and five-pin M12 electrical connectors. Standard voltage is 24 VDC. All assemblies are factory configured, piped, and tested before shipment. SISTEMA Library data is available at rosscontrols.com.

For safety engineers, plant managers, OEM machine builders, and procurement professionals specifying Category 4 pneumatic safety systems, the series represents the highest externally monitored safety tier in the ROSS Safe Air Entry Assembly portfolio. It is DGUV certified (German Statutory Accident Insurance), CE marked, UKCA marked, CSA certified, and CRN certified for applications across automotive manufacturing, metal fabrication, heavy industry, and any environment where the risk assessment identifies a Category 4, PL e requirement.

Key Engineering Features

• SERPAR Crossflow Technology - Category 4, PL e, SIL 3 - Proven ROSS SERPAR redundant crossflow design using two independent 3/2 NC dual poppet valve elements operating synchronously. Shuts off and exhausts downstream pressure even when one element faults, meeting the highest pneumatic safety category requirements.
• Dual Pressure Sensors for External Dynamic Monitoring - Two PNP solid state pressure sensors (one per valve element) provide real-time state information to the external safety controller. Dynamic cyclical monitoring on every actuation and de-actuation achieves the diagnostic coverage required for Category 4 per ISO 13849-1.
• EEZ-ON Soft-Start Option - Optional EEZ-ON Soft-Start module on 1/2 inch port size configurations ramps outlet pressure to approximately 50% of inlet before fully opening. Prevents sudden downstream pressure surges during startup, protecting personnel and equipment.
• DGUV Certified Safety Credentials - M35 Series valves carry DGUV (German Statutory Accident Insurance) functional safety certification (HSM 18019), CE, UKCA, EAC, CSA Certificate of Compliance, and CRN Certification, providing the broadest global safety certification coverage in the ROSS safe exhaust valve portfolio.
• Classic or Modular L-O-X Lockout Valve (15 Series) - OSHA 1910.147 and ANSI/ASSE Z244.1 compliant energy isolation. Large push/pull handle, lockable in OFF only, full-size exhaust port, integrated sensing port with pop-up indicator, and fluorocarbon slipper seals.
• MD Series Air Preparation with Metal or Polycarbonate Bowls - MD4 Series integrated filter/regulator with polycarbonate bowl (standard), or filter and pressure regulator with metal bowls. Optional lubricator with metal bowl. 5-micron filter, automatic drain, self-relieving regulator, analog gauge.
• LED Indicators for Rapid Troubleshooting - LED indicators on the M35 valve body provide visual status of each solenoid and pressure sensor, enabling rapid fault identification during commissioning and maintenance without requiring an external diagnostic tool.
• Five-Pin M12 Electrical Connectors - Two five-pin M12 connectors per valve (one per element) provide IP67-rated quick-disconnect electrical connections for solenoid and pressure sensor signals, simplifying wiring and allowing connector replacement in the field.
• Modular Port Connection - M35 valve has both modular receptacles and female threaded ports. Modular connection to ROSS MD Series filter-regulator units enables compact inline assembly. Bracket, screw, clamp, and mounting adapter required for modular mounting.
• Factory Assembled and Tested - Complete Series assemblies are factory configured, piped, leak tested, and function verified, reducing installation time and eliminating field assembly errors that could compromise Category 4 safety integrity.
• SISTEMA Library and Integration Guide Available - SISTEMA-compatible safety data and a detailed Integration Guide for the M35 Series are available at rosscontrols.com, covering operation, monitoring logic, and safety system integration.

Technical Specifications

General Specifications

Flow Performance Data

Certifications & Compliance

Typical Applications & Industries

Automotive Manufacturing - Category 4 Applications

• Automotive body shop robotic weld cells and stamping operations where Category 4, PL e is mandated by the risk assessment for energy isolation during robot reach-in maintenance and tooling changeovers.
• Automotive press lines and transfer presses where redundant safe exhaust is required to prevent unexpected actuation of pneumatic cylinders during die access procedures under OSHA 1910.147 and ANSI B11.3.
• Paint booth pneumatic actuation and material handling systems requiring Category 4 safe exhaust in potentially explosive atmospheres when explosion-proof solenoid variants are specified.
• Automotive component assembly stations with frequent operator interaction where the risk assessment specifies Category 4 to achieve PLr = PL e for the machine guarding safety function.

Metal Fabrication and Heavy Industry

• Hydraulic press brake air counterbalance systems where pneumatic cylinder energy must be reliably exhausted before die change or maintenance access, requiring Category 4 safe exhaust certification.
• Stamping presses and forging equipment where DGUV certification and ISO 13849-1 Category 4 compliance are required for European and export market machine safety declarations.
• Steel processing lines, coil handling systems, and heavy fabrication equipment where large actuator volumes demand high exhaust Cv and the EEZ-ON Soft-Start prevents shock loading during pressurization.
• Mining and heavy construction equipment with pneumatic energy storage systems where the redundant M35 dual poppet design provides the fail-to-safe behavior required at Category 4.

Packaging, Plastics, and General Industrial

• High-speed packaging lines and converting equipment where the risk assessment identifies Category 4 requirement due to high exposure frequency and severe injury potential from unexpected actuator movement.
• Injection molding and plastics processing equipment where the M35 Soft-Start prevents hydraulic shock in pneumatic circuits during mold open sequences.
• Semiconductor and electronics manufacturing with clean-room compatible assembly configurations requiring Category 4 documented safe exhaust.
• Food and beverage processing equipment requiring DGUV and CE certified Category 4 pneumatic safety for compliance with EU machinery directives and DGUV regulations.

Ordering and Model Number Configuration

The Series model number encodes the M35 valve configuration (with or without Soft-Start), port size and thread, FRL type, lockout valve type, extra port blocks, exhaust type, pressure monitoring device, and pin configuration. Standard voltage is 24 VDC. Refer to the M35 model number configurator for complete ordering information.

Port sizes: 1/2 (code 4) and 3/4 (code 5) for standard M35 valve.

Exhaust options: 40 = 1/2 built-in silencer; 50 = 3/4 built-in silencer; 46 = 1/2 threaded exhaust flange; 56 = 3/4 threaded exhaust flange.

Standard voltage: 24 VDC. Other voltages consult ROSS.

Pin configurations: AA (Solenoid A / Sensor A), AB (A/B), AC (A/C), CC (C/C), DB (D/B), DC (D/C).

Lockout position configurable before or after FRL.

Extra port blocks in 1/4, 3/8, or 1/2 inch; upstream, downstream, or both.

Analog gauge (G) and digital transducer (T) options.

Drip leg assemblies available (RCM35 series) for condensate-heavy environments.

Explosion-proof solenoid pilot available - consult ROSS.

Custom configurations available - consult ROSS.

SISTEMA Library and M35 Integration Guide downloadable at rosscontrols.com.

Accessories

Pressure Gauges, Transducers, and Indicators

Exhaust Silencers

External silencer for use with threaded exhaust flange option.

Warning: Exhaust silencer flow capacity must be at least as great as the valve exhaust capacity. Clogged silencers cause back pressure that impairs safe exhaust performance.

Prewired Electrical Connectors (M12 5-pin)

Lockout and Mounting Accessories

Replacement Filter Elements

Related Products & Accessories

• 1282 Series Safe Air Entry Assembly with MDC1 (Category 1, PL c) - Entry-level safe air entry assembly for Category 1, PL c applications. https://www.rosscontrols.com/en/series/1282-safe-air-entry-assembly-with-mdc1-series-safe-exhaust-valve
• 1283 Series Safe Air Entry Assembly with MDC Series (Category 1 and 2, PL c) - Scalable assembly for Category 1 or 2, PL c with MDC1 or MDC2 valve. https://www.rosscontrols.com/en/series/1283-safe-air-entry-assembly-with-mdc-series-safe-exhaust-valve
• 1284 Series Safe Air Entry Assembly with SV27 Series (Category 2, PL c, SIL 2) - Category 2, PL c assembly with SV27 force-guided DPST switch sensing valve. https://www.rosscontrols.com/en/series/1284-safe-air-entry-assembly-with-sv27-series-safe-exhaust-valve
• 1286 Series Safe Air Entry Assembly with DMC Series (Category 4, PL e, Internal Monitor) - Internally monitored Category 4, PL e assembly with DM1C or DM2C double valve. https://www.rosscontrols.com/en/series/1286-safe-air-entry-assembly-with-dmc-series-safe-exhaust-valve
• M35 Series Control Reliable Double Valves - Standalone M35 Series Category 4, PL e, SIL 3 safe exhaust double valves. https://www.rosscontrols.com/en/documents/367/m35-series-double-valves
• 15 Series L-O-X Lockout Valves - Classic and Modular L-O-X energy isolation valves. https://www.rosscontrols.com/en/series/1287-lockout-valves-15-series

Frequently Asked Questions (FAQ)

Q: What makes the M35 Series a Category 4, PL e double valve?

A: The M35 uses ROSS SERPAR crossflow technology with two independent 3/2 NC dual poppet valve elements operating synchronously. Each element has its own solenoid and pressure sensor. If one element faults (fails open, fails to shift, or degrades), the crossflow design ensures the system still shuts off supply and exhausts downstream pressure. This redundant architecture with dynamic monitoring achieves the Category 4 requirement of ISO 13849-1:2015 - a single fault does not cause loss of the safety function, and faults are detected before or during the next demand.

Q: What is SERPAR crossflow technology?

A: SERPAR is ROSS Controls' crossflow valve design used in redundant safe exhaust double valves. The two valve elements are connected in series on the supply side and with a crossflow path between them. This design ensures that if one element fails to close, the downstream side is still exhausted through the second element and the crossflow path. The result is a control-reliable system that provides safe exhaust even under single-fault conditions.

Q: How does external monitoring work with the M35 valve?

A: The M35 has two PNP solid state pressure sensors (one per valve element). The external safety controller reads both sensors on every machine cycle: verifying sensors indicate de-pressurized state when valves are de-energized, and pressurized state when energized. If either sensor shows an unexpected state, the controller halts machine operation and prevents restart until the fault is cleared. This dynamic cyclical monitoring provides the required diagnostic coverage for Category 4. The M35 Integration Guide from ROSS details the monitoring logic.

Q: What is the PFHD value for the M35 valve?

A: The M35 PFHD (Probability of Dangerous Failure per Hour) is 7.71 x 10^-9, with MTTFD of 301.9 years at 662,400 cycles per year (nop). These values are derived from the M35 catalog data and available in the SISTEMA Library file at rosscontrols.com.

Q: What is the EEZ-ON Soft-Start function?

A: The EEZ-ON Soft-Start module, available on 1/2 inch port size configurations, allows outlet pressure to ramp to approximately 50% of inlet pressure before the valve opens fully. This gradual pressurization prevents sudden shock loading of downstream cylinders, actuators, and tooling. It is particularly valuable in presses, forming machines, and clamping systems where sudden pressure application could cause unexpected movement.

Q: Does the M35 have internal or external monitoring?

A: The M35 Series uses external monitoring. The pressure sensors on each valve element provide state information to the customer's safety controller, which must implement the monitoring logic. This contrasts with internally monitored valves such as the DMC Series (1286 Series assembly) where monitoring logic is integral to the valve. If internal monitoring is required to simplify the safety system architecture, specify the 1286 Series with DMC valves.

Q: What is the difference between the series (M35) and 1286 Series (DMC) for Category 4 applications?

A: Both achieve Category 4, PL e, SIL 3. The key difference is monitoring type. The M35 in the series uses external monitoring: the customer's safety controller reads pressure sensors and implements fault detection logic. The DMC valves in the 1286 Series use internal monitoring: fault detection logic is integral to the valve, and the valve itself prevents restart on fault detection. Internal monitoring simplifies the safety controller architecture and cannot be inadvertently bypassed. Choose external when the safety controller handles the monitoring and the integration team can implement the monitoring logic correctly. Choose internal (1286) when simplified safety architecture and inherent non-bypassable monitoring are required.

Q: What certifications does the M35 hold?

A: The M35 Series holds DGUV certification (HSM 18019), CE marking, UKCA marking, EAC declaration, CSA Certificate of Compliance (for appropriately tested valves), and CRN Certification. It is certified to Category 4, PL e per ISO 13849-1:2015 and SIL 3 per IEC 62061. Testing to BS EN 60068-2-27 for vibration and impact resistance is also documented.

Q: Can the assembly be used without a lockout valve?

A: The L-O-X lockout valve code in the model number includes 'X' (none) as an option. However, for OSHA 1910.147 and ANSI/ASSE Z244.1 compliance in North American installations, a lockout valve is required as the energy isolation device for lockout/tagout procedures. Removing the lockout valve from the assembly does not satisfy LOTO requirements. Consult ROSS for configurations without integral lockout where a separate energy isolation device is installed upstream.

Q: Are drip leg configurations available?

A: Yes. RCM35 series drip leg assemblies incorporate an optional drip leg with inlet and drain ball valves for condensate-heavy environments. Two types are available: Type C (Classic L-O-X with separate F/R with metal bowls) and Type M (Modular L-O-X with Integrated F/R with polycarbonate bowl). Consult the M35 catalog for RCM35 model number configurator.

Q: What M12 connector pin configuration should I specify?

A: The M35 valve offers six pin configuration combinations determined by the solenoid connector type (A, C, or D) and pressure sensor connector type (A, B, or C): AA, AB, AC, CC, DB, DC. The correct combination depends on your safety controller's I/O module requirements. Refer to the M35 catalog connector pinout diagrams and consult your safety controller vendor for compatible M12 pin assignments.

Q: What is the minimum operating pressure?

A: Minimum operating pressure is 30 psig (2 bar). Both solenoids must receive adequate pilot pressure for reliable shifting. Ensure the upstream pressure regulator maintains at least 30 psig at all times during machine operation.

Q: Can the assembly handle condensate-heavy environments?

A: Yes. The RCM35 drip leg assembly option adds a drip leg with ball valve drain upstream of the main assembly for applications with significant condensate in the compressed air supply. Standard assemblies use MD4 or MD3 Series FRL with automatic filter drain and 5-micron filtration, which handles normal industrial air quality per ISO 8573-1 Class 7:4:4.

Installation & Maintenance Guidelines

• Mount in any orientation; vertical preferred for condensate drainage from FRL bowls.
• Supply filtered compressed air meeting ISO 8573-1 Class 7:4:4 minimum.
• Do not restrict supply lines or exhaust ports. Exhaust port back pressure degrades safe exhaust performance.
• Connect both M35 solenoids to external safety controller. Both must be energized and de-energized synchronously.
• Connect both M35 pressure sensors to external safety controller. Implement dynamic cyclical monitoring per M35 Integration Guide available from ROSS Controls.
• Program safety controller to verify sensor states on every machine cycle and halt operation on any detected fault.
• Position L-O-X lockout valve per facility LOTO program. Lockout valve is an energy isolation device - NOT an emergency stop.
• For modular mounting to MD Series FRL units, use bracket (R-A118-105M). Ensure all modular joints are fully seated.
• Exhaust silencer (when used with threaded exhaust flange) must have flow capacity at least as great as valve exhaust capacity.
• After installation, perform complete functional test: lockout, FRL settings, M35 energization/de-energization, pressure sensor signals, LED indicators, and controller fault response to simulated sensor fault.
• Establish periodic maintenance schedule per M35 Installation Instructions. Inspect filter elements, FRL bowl, solenoids, pressure sensors, and M12 connectors.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all products, covering defects in material and workmanship from date of purchase.

Global technical support available through ROSS offices in USA, Canada, Brazil, Germany, France, UK, India, China, and Japan.

Customer Service: 1-800-GET-ROSS (1-800-438-7677). Technical Service: 1-888-TEK-ROSS (1-888-835-7677).

M35 Integration Guide available from ROSS Controls for operation, monitoring implementation, and safety system integration guidance.

For complete technical data, dimensional drawings, SISTEMA Library files, and product configurator, visit rosscontrols.com.

Download Catalog: https://www.rosscontrols.com/en/documents/367/m35-series-double-valves