Safe Air Entry Assembly with MDC1 Series Safe Exhaust Valve Safety Category 1, PL c, Externally Monitored

Product Overview

The ROSS Controls is a pre-engineered Safe Air Entry Assembly that pairs the MDC1 Series single poppet safe exhaust (dump) valve with a 15 Series L-O-X Lockout valve and MD Series air preparation components. Designed for Safety Category 1, Performance Level c (externally monitored) applications per ISO 13849-1:2015, this assembly provides reliable pneumatic energy isolation, air conditioning, and safe exhaust in a single factory-tested unit.

The MDC1 Series valve at the heart of this assembly uses a 3/2 normally closed single poppet design that shuts off the supply of pneumatic energy and exhausts downstream pressure to atmosphere when de-energized. Without a solid state pressure sensor, the MDC1 is specified for Category 1 applications where the external safety control system provides the required monitoring function. The EEZ-ON Soft-Start function, available on the 1/2 inch body size, allows gradual downstream pressure buildup during startup to protect 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, a filter, integrated filter/regulator, or filter/regulator/lubricator with metal bowls for air quality conditioning, and the MDC1 safe exhaust valve with integrated silencer. All components are factory configured, piped, and tested before shipment. SISTEMA Library data is available for download from rosscontrols.com to support safety function calculations.

For design engineers, procurement specialists, and OEM machine builders specifying entry-level pneumatic safety systems, the series provides a straightforward path to Category 1, PL c compliance with minimal field assembly effort. The modular construction supports custom port sizing, lockout valve positioning, FRL configuration, and optional accessories including pressure gauges and extra port blocks.

Key Engineering Features

• MDC1 Series Single Poppet Safe Exhaust Valve - 3/2 normally closed single poppet design shuts off pneumatic energy supply and exhausts downstream pressure without a pressure sensor, providing Category 1 safety function when externally monitored.
• EEZ-ON Soft-Start Function (1/2 inch body) - Allows outlet pressure to increase gradually during startup, reaching approximately 50% of inlet pressure before opening fully. Protects personnel and downstream equipment from sudden pressure surges.
• Classic or Modular L-O-X Lockout Valve - 15 Series L-O-X valve provides OSHA 1910.147 and ANSI/ASSE Z244.1 compliant energy isolation. Large push/pull handle, lockable in OFF position only, full-size exhaust port, integrated sensing port with pop-up indicator, and fluorocarbon slipper seals for reliable shifting after extended idle.
• MD Series Air Preparation with Metal Bowls - Filter, integrated filter/regulator, or filter/regulator/lubricator with metal bowls conditions compressed air supply to the safe exhaust valve. 5-micron filter element, automatic filter drain, self-relieving pressure regulator, and analog gauge included.
• Factory Assembled and Tested - Every Series assembly is fully configured, leak tested, and performance verified before shipment, eliminating field assembly errors and reducing installation time significantly.
• Inline/Modular Mounting - 1/2 inch body size supports inline or modular connection to MD Series filter-regulator units. 1 inch body size is inline only. Bracket, screw, clamp, and mounting adapter available for modular mounting.
• Integrated Exhaust Silencer - Built-in clog-resistant silencer on the MDC1 valve reduces exhaust noise at the point of exhaust without requiring external silencer selection or pipe routing.
• SISTEMA Library Support - SISTEMA-compatible safety data for the MDC1 valve is available for download at rosscontrols.com, enabling direct import into safety system calculations to verify Category 1, PL c achievement.
• Explosion-Proof Solenoid Pilot Option - Explosion-proof solenoid pilot versions are available for hazardous area installations. Consult ROSS Controls for Class I Division 1/2 options and custom configurations.
• Configurable Extra Port Blocks - Optional extra port blocks in 1/4, 3/8, or 1/2 inch sizes can be installed upstream, downstream, or both to provide additional connection points for gauges, transducers, sensors, or branch circuits.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

General Machine Guarding - Category 1 Applications

• Machine tools, lathes, mills, and grinding equipment where controlled pneumatic energy removal during maintenance access requires a compliant Category 1 safe exhaust function with external safety controller monitoring.
• Conveyor systems and material handling equipment with periodic maintenance access needs where the safety controller verifies MDC1 valve state on each cycle.
• Packaging machinery including form-fill-seal, case erectors, and labeling lines where Category 1 pneumatic safety integrated with the machine PLC satisfies the risk assessment requirement.
• Printing presses and converting equipment where operators perform setup and web threading operations requiring safe pneumatic energy removal per ISO 13849-1 Category 1.
• Agricultural and food processing equipment where the FRL assembly ensures clean, regulated air reaches the safe exhaust valve and downstream actuators.
• Assembly automation cells where the EEZ-ON Soft-Start function on the MDC1 1/2 inch body prevents shock loading of downstream cylinders and tooling during system pressurization.

Pneumatic Control and Air Dump/Release Applications

• Pneumatic clamping and fixturing systems on machining centers where a controlled Category 1 air dump allows safe workpiece loading and unloading without full system de-energization.
• Blow-off and air knife systems where the MDC1 valve provides safe on/off control and the Soft-Start prevents sudden air blasts during startup.
• Pneumatic press and forming systems requiring Category 1 compliant safe exhaust before operator access to the tooling zone.
• Automated test stands where the safe air entry assembly provides controlled pressurization and safe exhaust for pneumatic test circuits.

Ordering and Model Number Configuration

The Series uses a model number structure that encodes the MDC1 valve configuration, body/port size, lockout valve type, and FRL options. All assemblies are factory configured and tested. For configurations not shown, consult ROSS Controls.

MDC1 Series (Category 1, no pressure sensor) is the valve used in the series assemblies.

Body size 1/2 inch supports port sizes from 3/8 inch to 3/4 inch with inline or modular mounting and EEZ-ON Soft-Start.

Body size 1 inch supports port sizes from 3/4 inch to 1-1/4 inch with inline mounting.

Voltage standard is 24 VDC. For other voltages, consult ROSS Controls.

Electrical connection options include DIN EN 175301-803 Form C and M12.

Thread types: NPT (North America standard) and G/BSPP (international).

Lockout valve can be positioned before or after the FRL components depending on application requirements.

Extra port blocks in 1/4, 3/8, or 1/2 inch sizes can be located upstream, downstream, or both.

Analog pressure gauge and digital transducer options available.

Explosion-proof solenoid pilot available for hazardous locations - consult ROSS.

SISTEMA Library data downloadable at rosscontrols.com for safety calculations.

Accessories

Pressure Gauges and Transducers

Analog gauges and digital transducers for downstream pressure monitoring.

Exhaust Silencers

External exhaust silencers for additional noise reduction when remote exhaust routing is required.

Warning: Exhaust silencers must have flow capacities at least as great as the exhaust capacities of the valves. Contaminated or clogged silencers cause back pressure that can degrade safe exhaust performance.

Prewired Electrical Connectors

Prewired connector sets for solenoid and sensor connections.

Lockout and Mounting Accessories

Replacement Filter Elements

Related Products & Accessories

• 1283 Series Safe Air Entry Assembly with MDC Series (Cat 1 and 2) - Safe Air Entry Assembly incorporating MDC1 (Category 1) and MDC2 (Category 2) safe exhaust valves with solid state pressure sensor for external monitoring up to Category 2, PL c. 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 - Safe Air Entry Assembly with SV27 Series sensing valve for Category 2, PL c externally monitored applications using force-guided DPST switch feedback. https://www.rosscontrols.com/en/series/1284-safe-air-entry-assembly-with-sv27-series-safe-exhaust-valve
• 1285 Series Safe Air Entry Assembly with M35 Series - Safe Air Entry Assembly with M35 Series redundant double valve for Category 4, PL e externally monitored applications. https://www.rosscontrols.com/en/series/1285-safe-air-entry-assembly-with-m35-series-safe-exhaust-valve
• 1286 Series Safe Air Entry Assembly with DMC Series - Safe Air Entry Assembly with DM1C or DM2C Series internally monitored double valve for Category 4, PL e applications. https://www.rosscontrols.com/en/series/1286-safe-air-entry-assembly-with-dmc-series-safe-exhaust-valve
• MDC1 Series Single Valve - Standalone MDC1 Series 3/2 NC single poppet safe exhaust valve for Category 1 applications. https://www.rosscontrols.com/en/series/mdc1
• 15 Series L-O-X Lockout Valves - Classic and Modular L-O-X lockout valves for energy isolation per OSHA 1910.147 and ANSI/ASSE Z244.1. https://www.rosscontrols.com/en/series/1287-lockout-valves-15-series

Frequently Asked Questions (FAQ)

Q: What is the difference between the series and the 1283 Series Safe Air Entry Assemblies?

A: The Series uses only the MDC1 valve, which has no solid state pressure sensor, and is rated for Category 1, PL c with external monitoring only. The 1283 Series offers both MDC1 (Category 1) and MDC2 (Category 2) valve options. The MDC2 incorporates a solid state pressure sensor that feeds back valve state information to the external safety controller, enabling up to Category 2, PL c. When higher diagnostic coverage is required by the risk assessment, specify the 1283 Series with MDC2.

Q: What does 'externally monitored' mean for the MDC1 valve?

A: Externally monitored means the safety function relies on the customer's safety control system (PLC, safety relay, or safety controller) to verify the MDC1 valve has performed its function. Unlike internally monitored valves such as the DMC Series, the MDC1 does not include self-diagnostic circuitry. The external controller must monitor the valve state on each machine cycle using appropriate feedback signals and halt machine operation if a fault is detected.

Q: What safety category and PL level does the series achieve?

A: The Series with MDC1 valves achieves Safety Category 1, Performance Level c (PL c) per ISO 13849-1:2015 when used with proper external safety controls providing the required monitoring function. The SISTEMA Library data available at rosscontrols.com provides the required safety parameters to verify this in your safety calculations.

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

A: EEZ-ON is ROSS Controls' trademarked Soft-Start function available on the MDC1 1/2 inch body size. On energization, the valve allows outlet pressure to increase at a reduced rate until reaching approximately 50% of inlet pressure. At that point the valve opens fully to complete pressurization at full rate. This gradual startup protects personnel from sudden pressure surges and prevents shock loading of downstream cylinders, tooling, and piping.

Q: Does the MDC1 valve require in-line lubrication?

A: No. PTFE backup piston rings in the MDC1 valve enable reliable operation with or without in-line lubrication. However, if a lubricator is included in the FRL assembly for other downstream components, the MDC1 valve is compatible with petroleum-based lubricants per DIN 51519.

Q: Can the lockout valve be positioned downstream of the FRL?

A: Yes. The L-O-X lockout valve position is configurable in the model number. It can be located upstream (before) or downstream (after) the FRL components based on application requirements and facility energy isolation procedures. Consult ROSS Controls for guidance on lockout valve positioning relative to your specific installation.

Q: What air quality is required?

A: The MDC1 valve and all assembly components require filtered compressed air meeting ISO 8573-1 Class 7:4:4 as a minimum. The integrated 5-micron filter in the MD Series FRL provides this filtration. Ensure the upstream air supply is clean and dry, and replace filter elements on a regular maintenance schedule.

Q: Are explosion-proof versions available?

A: Yes. Explosion-proof solenoid pilot versions of the MDC1 valve are available for hazardous area installations classified as Class I, Division 1 or 2. Contact ROSS Controls directly for hazardous area product configurations and applicable certifications.

Q: What voltages are available?

A: The standard voltage is 24 VDC. Other voltages are available by consulting ROSS Controls. Note that in the United States, OSHA regulations limit control voltage to no more than 120 VAC, so 230 VAC options are not available for domestic U.S. applications.

Q: What does the SISTEMA Library file provide?

A: The SISTEMA Library file provides the safety parameters for the MDC1 valve including PFH (Probability of Failure per Hour), MTTFD (Mean Time to Dangerous Failure), B10 values, and DC (Diagnostic Coverage) data. These values import directly into the SISTEMA software tool used to calculate PL achievement per ISO 13849-1. Download the file at rosscontrols.com.

Q: Can this assembly be used to control clutch/brake mechanisms on mechanical power presses?

A: No. Per ROSS Controls specifications and applicable regulations, these valve assemblies are not designed for controlling clutch/brake mechanisms on mechanical power presses. For mechanical power press control, consult ROSS Controls for appropriate press control valve products.

Q: What is the minimum operating pressure?

A: The minimum operating pressure is 30 psig (2 bar). Supply pressure below this threshold may result in incomplete valve shifting and unreliable safe exhaust function. Ensure the upstream pressure regulator maintains at least 30 psig at all times during machine operation.

Q: Are CAD models available?

A: Yes. 2D drawings and 3D CAD models in multiple formats are available for download at rosscontrols.com. These support machine design integration and reduce engineering lead time for OEM builders.

Q: What is the maximum operating pressure?

A: The maximum operating pressure for all Series assembly components is 150 psig (10.3 bar). Do not exceed this limit on any port of the assembly.

Installation & Maintenance Guidelines

• Mount in any orientation. Vertical mounting is preferred for optimal condensate drainage from the FRL bowl.
• Supply filtered compressed air meeting ISO 8573-1 Class 7:4:4 or better to maximize assembly life and prevent contaminants from interfering with valve sealing.
• Do not restrict supply lines or exhaust ports. Restrictions can reduce pressure below the 30 psig minimum and impair safe exhaust performance.
• Connect the MDC1 solenoid to the external safety control system per the Integration Guide available from ROSS Controls. The external controller must verify valve state on each machine cycle.
• Position the L-O-X lockout valve before or after the FRL based on your facility energy isolation procedure and lockout/tagout program requirements.
• Install appropriate compressed air dryer or moisture separator upstream if operating in high-humidity environments to prevent condensate accumulation in filter bowls.
• Verify that any exhaust silencers have flow capacities at least as great as the valve exhaust capacities. Contaminated or clogged silencers cause back pressure that degrades safe exhaust performance.
• For modular mounting, use the bracket, screw, clamp, and mounting adapter kit (R-A118-105M). Ensure all modular joints are properly seated and secured.
• Note: The L-O-X lockout valve is defined as an energy isolation device per OSHA 1910.147 and ANSI/ASSE Z244.1 and is NOT an emergency stop device.
• After installation, perform a complete functional test: verify lockout operation, FRL pressure settings, MDC1 energization/de-energization, exhaust function, and safety controller feedback signal continuity.
• Establish a periodic maintenance schedule for filter element inspection and replacement. Replace 5-micron elements when pressure drop across the filter exceeds 7 psig (0.5 bar) or per the facility maintenance program.

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 is available through ROSS offices in the USA (headquarters in Ferndale, Michigan), Canada, Brazil, Germany, France, United Kingdom, India, China, and Japan.

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

For complete technical data, dimensional drawings, SISTEMA Library files, and product configurator access, visit rosscontrols.com or contact ROSS Controls directly.

Download Catalog: https://www.rosscontrols.com/en/series/1282-safe-air-entry-assembly-with-mdc1-series-safe-exhaust-valve