MDC1 Series Single Valve Safety Category. 1, PL c without Monitoring

Product Overview

The ROSS Controls MDC1 Series is a single-valve safe exhaust solution designed to block pneumatic supply and rapidly vent residual downstream pressure from industrial machinery during shutdown, maintenance, and employee access events. When properly integrated with appropriate safety controls, the MDC1 Series achieves Safety Category 1, Performance Level c (PL c) per ISO 13849-1:2015, making it the entry-level platform in the ROSS MDC family for applications where external diagnostic monitoring is not required.

The MDC1 Series operates on a fail-to-safe principle using a three-position, two-way solenoid-controlled poppet design. When the solenoid is energized, the valve opens to supply compressed air to the downstream machine zone. Upon de-energization, the valve simultaneously closes the supply port and opens a dedicated exhaust port, rapidly eliminating residual pneumatic pressure that could otherwise cause unexpected machine motion and personnel injury.

At the core of the MDC1 is ROSS's proven single-poppet design, which provides inherent dirt tolerance, wear compensation, and positive shutoff. Unlike spool-type valves that rely on close-tolerance sliding surfaces, the poppet's face-seal geometry eliminates internal bypass leakage paths and self-compensates for seal wear over millions of cycles. PTFE backup piston rings further extend service life by reducing friction and enabling reliable operation with or without in-line air lubrication.

The optional EEZ-ON soft-start function controls the rate of system pressurization on energization, allowing outlet pressure to rise gradually until it reaches approximately 50 percent of inlet pressure, at which point the valve transitions to full flow. This prevents sudden pressure surges that can cause equipment shock loads, component damage, or unexpected actuator motion, particularly important during initial startup or after emergency stop events.

The MDC1 Series is available in 1/2 inch and 1 inch body sizes with a B10D reliability rating of 5 million cycles. Both threaded NPT and G port connections are offered, and modular port configurations allow direct integration into ROSS Air Entry Systems alongside Lockout L-O-X valves and MD Series FRL units. SISTEMA Library files are available for download to simplify safety function verification and documentation in accordance with ISO 13849.

Key Engineering Features

• Safety Category 1, PL c (ISO 13849-1:2015) - Achieves Category 1, Performance Level c when integrated with proper safety controls, satisfying machine safety risk reduction requirements for moderate-risk pneumatic applications.
• Fail-to-Safe Poppet Design - The fail-to-safe safety function is ensured as long as the poppet returns to its start position upon de-energization. Simultaneous supply shutoff and downstream exhaust eliminate residual pressure hazards.
• Dirt-Tolerant, Wear-Compensating Poppet - Poppet face-seal geometry provides inherent dirt tolerance and automatic wear compensation for sustained quick response and high flow capacity throughout the valve's service life.
• PTFE Backup Piston Rings - Enhances valve endurance and enables reliable operation with or without in-line air lubrication, reducing maintenance requirements in industrial environments.
• EEZ-ON Soft-Start (Optional) - Gradual pressurization on energization, increasing outlet pressure at a controlled rate to approximately 50 percent of inlet before transitioning to full flow, preventing shock loads and unexpected machine motion.
• Threaded or Modular Port Connection - Threaded NPT or G ports for direct piping, plus modular port configurations for seamless connection to ROSS Air Entry System assemblies including Lockout L-O-X valves and MD Series FRLs.
• Threaded Exhaust Port - Dedicated threaded exhaust port accommodates canister silencers or remote exhaust piping, allowing noise reduction and flexible exhaust routing in the machine enclosure.
• B10D Rating: 5 Million Cycles - High reliability rating confirms suitability for mission-critical safety applications requiring extensive service life documentation per ISO 13849-1 MTTFD calculations.
• SISTEMA Library Support - Downloadable SISTEMA Library files enable engineers to efficiently document and verify safety function performance levels in compliance with ISO 13849-1.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

Metal Forming and Stamping

• Mechanical power presses and stamping lines where downstream pneumatic energy must be exhausted before die changes or tooling maintenance to eliminate unexpected ram movement.
• Tube bending and forming machines requiring controlled removal of clamp and support cylinder pressure before operator access to the work zone.
• Roll forming lines where segment drives and guide actuators must be fully depressurized during roll change procedures.

Automotive Assembly and Body Fabrication

• Robotic welding cell pneumatic utility supply isolation during tool change or maintenance access, ensuring welding gun actuators and part clamps are de-energized.
• Body-in-white fixture actuators in assembly jigs where MDC1 valves exhaust residual clamping pressure before operators approach the fixture.
• Paint and sealing application equipment requiring pressure removal from spray guns and dispensing actuators during color change or cleaning cycles.

Packaging and Material Handling

• Automated case erecting, filling, and palletizing lines where pneumatic grippers, pushers, and transfer slides must be exhausted before maintenance access.
• Conveyor divert and accumulation systems requiring controlled pneumatic shutdown to prevent unexpected actuator travel during jam clearance.
• Stretch wrapping and banding equipment where piston actuators must be de-pressurized before operator interaction with the wrapping zone.

General Industrial Manufacturing

• Injection molding and plastics processing machines where clamping cylinder circuits must be exhausted prior to mold access or part removal from stuck conditions.
• Assembly automation lines with pneumatically driven screwdrivers, riveters, and press units that require energy removal during machine lockout/tagout procedures.
• Woodworking and furniture manufacturing equipment where pneumatic hold-down clamps and panel presses must be safely de-pressurized during work zone access.
• Food and beverage processing equipment requiring pneumatic circuit isolation during sanitation and changeover procedures in compliance with hygiene safety standards.

Test and Measurement Systems

• Pneumatic leak test fixtures and pressure cycling systems where actuator circuits must be exhausted between test cycles or during fixture loading and unloading.
• Component assembly test stands requiring controlled pressure removal from test tooling actuators during DUT (device under test) changeover.

Material Handling and Lifting

• Pneumatic lift assists and tilting tables in ergonomic workstations where supply isolation and exhaust are required when the unit is in the lowered, safe position.
• Dock levelers and transfer car pneumatic drives requiring safe pressure removal during access for maintenance or product transfer operations.

Ordering and Model Number Configuration

The MDC1 Series is configured using a structured model number that defines body size, soft-start option, port type, voltage, and electrical connection. Contact ROSS Controls or your authorized distributor for the complete model configurator and available variants. Example model numbers include MDC1E131GAEXCGA (1/2" body, with soft-start, NPT, 24 VDC).

Standard voltage: 24 VDC. Contact ROSS for other voltage options.

Soft-start EEZ-ON option available; specify at time of ordering.

NPT and G (BSPP) thread options available. Specify thread type when ordering.

Modular port configuration available for direct connection to ROSS Air Entry System components.

SISTEMA Library files downloadable from the ROSS Controls website for ISO 13849-1 safety documentation.

Contact ROSS Controls at (800) 438-7677 or rosscontrols.com for full variant listing, dimensional drawings, and custom configurations.

Accessories

Canister Exhaust Silencers

Threaded canister-style silencers for installation on the MDC1 exhaust port to reduce pneumatic noise levels at the exhaust point. Required to meet OSHA noise exposure limits in facilities where exhaust sound pressure levels exceed permissible thresholds.

ROSS MD Series FRL Units

Filter-Regulator-Lubricator units with modular port interfaces compatible with the MDC1 modular port option, enabling complete Air Entry System assemblies with lockout, filtration, regulation, and safe exhaust in a single engineered package.

Lockout L-O-X Valves

Manual lockout valves for upstream energy isolation in conjunction with the MDC1 safe exhaust valve, enabling complete lockout/tagout compliance per OSHA 29 CFR 1910.147 and ANSI Z244.1.

Analog Pressure Gauges and Digital Pressure Transducers

Optional pressure measuring devices for downstream pressure verification, available in 0 to 145 psig (0 to 10 bar) ranges. Digital transducers provide 4-20 mA output for integration with PLC-based monitoring systems.

Related Products & Accessories

• MDC2 Series Single Valve (Category 2, PL c) - The MDC2 adds an integrated solid-state pressure sensor for external monitoring, upgrading to Category 2 with 60-90% diagnostic coverage. https://www.rosscontrols.com/en/series/1292-mdc2-series-single-valve
• SV27 Series Single Valve (Category 2, PL c with DPST) - 27 Series-based sensing valve with integrated DPST safety switch for 99% diagnostic coverage in Category 2 applications. https://www.rosscontrols.com/en/series/1293-sv27-series-single-valve
• DM1 Series C Double Valve (Category 4, PL e) - Redundant dual-poppet double valve with internal dynamic monitoring and automatic reset for the highest safety category applications. https://www.rosscontrols.com/en/series/1294-dm1-series-c-double-valve
• DM2C Series Double Valve (Category 4, PL e, Manual Reset) - Redundant dual-poppet double valve with internal dynamic monitoring and manual (solenoid) reset for latching fault memory. https://www.rosscontrols.com/en/series/1295-dm2c-series-double-valve
• Safe Air Entry Assembly with MDC Series - Complete air entry system integrating Lockout L-O-X valve, MD Series FRL, and MDC1 or MDC2 safe exhaust valve in a single assembly. https://www.rosscontrols.com/en/series/1285-safe-air-entry-assembly-with-mdc-series-safe-exhaust-valve
• Lockout L-O-X Valves (15 Series) - Manual lockout valves for pneumatic energy isolation per OSHA lockout/tagout requirements. https://www.rosscontrols.com/en/series/1287-lockout-valves-15-series

Frequently Asked Questions (FAQ)

Q: What safety performance does the MDC1 Series achieve?

A: The MDC1 Series achieves Safety Category 1, Performance Level c (PL c) per ISO 13849-1:2015 when integrated with proper safety controls. It also carries SIL 1 certification per IEC 61508:2001. Category 1 is appropriate for applications where the B10D rating and proof test interval satisfy the calculated MTTFD requirements and where the nature of the safety function does not require diagnostic monitoring.

Q: What is the difference between the MDC1 and MDC2 Series?

A: The MDC1 Series does not include an integrated pressure sensor and achieves Category 1, PL c without monitoring. The MDC2 Series adds an integrated solid-state pressure sensor that, when monitored by an external safety control system on each actuation and de-actuation cycle, provides 60 to 90 percent diagnostic coverage and upgrades performance to Category 2, PL c.

Q: What is the fail-to-safe operating principle of the MDC1?

A: On de-energization of the solenoid, the MDC1 valve simultaneously closes the supply port and opens the exhaust port, removing downstream pneumatic energy from the machine circuit. The fail-to-safe function is maintained as long as the poppet is able to return to its start position. The poppet design with wear compensation ensures this return motion is sustained throughout the valve's service life.

Q: What is the EEZ-ON soft-start function and when should I specify it?

A: The optional EEZ-ON soft-start module controls the rate of downstream pressurization when the MDC1 solenoid is energized. It restricts initial airflow through an adjustable needle valve, allowing outlet pressure to increase gradually until it reaches approximately 50 percent of inlet pressure, at which point the valve transitions to full flow. Specify soft-start for applications where sudden pressurization could cause equipment shock loads, unexpected actuator motion, or product quality defects during machine restart.

Q: What port sizes and body sizes are available?

A: The MDC1 Series is available in 1/2 inch and 1 inch body sizes. Flow capacity ranges from 3.1 Cv (3,100 Nl/min) for the 1/2 inch body to 30 Cv (30,000 Nl/min) for the 1 inch body. Multiple port size combinations within each body size are available. Contact ROSS Controls for the complete variant matrix.

Q: What is the operating pressure range?

A: The 1/2 inch body MDC1 operates from 30 to 150 psig (2.0 to 10.3 bar). The 1 inch body operates from 36 to 150 psig (2.5 to 10.3 bar). All variants use internal pilot supply from the inlet pressure.

Q: Can the MDC1 be used for OSHA lockout/tagout compliance?

A: The MDC1 provides the automatic de-energization and exhaust function required for pneumatic energy control as part of a lockout/tagout program. For full compliance with OSHA 29 CFR 1910.147, the MDC1 must be used in conjunction with an upstream manual lockout device such as the ROSS Lockout L-O-X valve, which provides the physical energy isolation and mechanical lockout capability required by the standard.

Q: Are NPT and BSPP (G) threads both available?

A: Yes. Both NPT and G (BSPP) thread options are available. Specify the required thread type when ordering. Modular port configurations are also available for direct connection to ROSS MD Series Air Entry System components without pipe fittings.

Q: Does the MDC1 require in-line lubrication?

A: No. PTFE backup piston rings and the poppet design enable reliable operation without in-line lubrication. If lubrication is used, it should be a mineral oil per DIN 51519, viscosity class 32 to 46. Avoid synthetic lubricants with phosphate ester or other seal-incompatible additives.

Q: What filtration is required upstream of the MDC1?

A: Filtered compressed air is required. A 5-micron particulate filter upstream of the valve is recommended to protect the poppet seat and seals from contamination-related damage. Air quality should meet ISO 8573-1 Class 7:4:4 or better.

Q: What is the B10D value and how is it used in safety calculations?

A: The MDC1 has a B10D reliability rating of 5,000,000 cycles. B10D represents the number of cycles at which 10 percent of a population of components can be expected to have experienced a dangerous failure. This value is used in ISO 13849-1 MTTFD calculations to determine the achievable Performance Level for a given application's operating cycle frequency and mission time.

Q: Is a SISTEMA Library file available?

A: Yes. A SISTEMA Library file is available for download from the ROSS Controls website. SISTEMA is the software tool published by the IFA (Institut fur Arbeitsschutz) for verifying ISO 13849-1 safety function performance levels. The ROSS SISTEMA file contains the required safety parameters (B10D, PFHD, MTTFD, diagnostic coverage) for the MDC1 Series, eliminating manual data entry and reducing documentation errors.

Q: What are the temperature limits for the MDC1?

A: The MDC1 operates with an ambient temperature range of 40 to 120 F (4 to 50 C) and a media temperature range of 40 to 175 F (4 to 80 C). For applications outside these ranges, contact ROSS Controls to evaluate suitability.

Q: What warranty and support does ROSS provide?

A: ROSS Controls provides a one-year warranty covering defects in material and workmanship. Technical support is available at (800) 438-7677 or 1-888-TEK-ROSS. ROSS maintains global support through offices in the USA, Canada, Germany, France, United Kingdom, Brazil, India, China, and Japan.

Installation & Maintenance Guidelines

• Install MDC1 in the supply line immediately upstream of the machine zone or circuit to be protected. Position the valve so that all actuators, cylinders, and pneumatic devices within the protected zone are downstream of the MDC1 exhaust port.
• Supply filtered, regulated compressed air meeting ISO 8573-1 Class 7:4:4. Use a 5-micron or finer filter upstream to protect poppet seat surfaces from particulate damage.
• Ensure inlet pressure remains within the operating pressure range: 30 to 150 psig (2.0 to 10.3 bar) for 1/2" body; 36 to 150 psig (2.5 to 10.3 bar) for 1" body. Operating below minimum pressure may result in incomplete or slow exhaust.
• Do not restrict the exhaust port. Install a silencer sized to provide at least the same flow capacity as the valve exhaust capacity. Restricted exhaust causes back pressure and slows downstream depressurization.
• Wire the solenoid to the machine safety control system as specified in the safety function design. The MDC1 must be de-energized (solenoid off) to achieve the safe exhaust condition.
• If using the modular port configuration, ensure all unused ports are plugged and port block seals are properly seated before pressurizing the system.
• Perform a functional test after installation: energize the solenoid to supply air, then de-energize and verify that downstream pressure drops to zero within the required exhaust time.
• For EEZ-ON soft-start equipped valves, adjust the needle valve to achieve the desired pressurization rate. A controlled pressurization rate of 2 to 5 seconds is typical for most machine restart applications.
• Conduct periodic proof testing of the safety function at intervals determined by the risk assessment and calculated nop (number of operations per year) to maintain the required Performance Level throughout the machine's mission time.
• Document the installation, functional test results, and periodic test records as required by ISO 13849-1 and applicable safety standards.

Warranty & Global Support

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

Technical support is available by telephone at 1-888-TEK-ROSS (1-888-835-7677) and customer service at 1-800-GET-ROSS (1-800-438-7677).

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

SISTEMA Library files, dimensional drawings, CAD models, and product certifications are available for download at rosscontrols.com.

For Safety Function Selection Guides, integration guidance, and application engineering support, contact ROSS Controls at rosscontrols.com or call (800) 438-7677.

Download Catalog: https://www.rosscontrols.com/en/documents/5549