MDC Series Safety Exhaust Valves with EEZ-ON® Operating Instructions

Overview

The ROSS Controls MDC Series consists of MDC1 and MDC2 single-body safety exhaust (dump) valves with integrated EEZ-ON® (Soft-Start) capability. These valves provide controlled, gradual pressure build-up to downstream systems when energized, while exhausting all downstream pressure rapidly when de-energized or when a fault occurs. The MDC Series is designed for applications requiring Category 1 PL c or Category 2 PL C safety performance.

Published under operating instructions document RC-MDC-OI, the MDC Series is available in two configurations: with EEZ-ON® soft-start (MDC1E/MDC2E models) and without EEZ-ON® soft-start (MDC1X/MDC2X models). Both configurations support optional pressure sensing through an integral pressure sensor, and both are designed for external monitoring via appropriate safety control systems.

The MDC Series operating pressure range is 36 to 150 psig (2.5 to 10 bar). Product key codes allow selection of body size (1/2 or 1), soft-start on/off, voltage, feedback signal type (external or none), pressure measuring device (analog gauge G, digital transducer T, or none X), monitoring, and NPT port sizes for exhaust (3/8, 3/4). ROSS Controls has been manufacturing innovative fluid power products since 1921.

Key Features

EEZ-ON® Soft-Start Integration

The MDC Series with EEZ-ON® module (E models) provides controlled pressure ramp-up when the valve is energized. This protects actuators, tooling, and downstream equipment from sudden pressure shocks during machine restart after a safety stop. The EEZ-ON® function is a ROSS Controls patented innovation, integrated directly into the MDC valve body for compactness and reliability.

Flexible Pressure Sensing and Communication Options

The MDC Series supports multiple feedback and communication options. Pressure measuring devices include an analog gauge (G) or digital pressure transducer (T), or no device (X). Feedback signal types include external (E) and communication outputs. This flexibility allows the MDC Series to integrate into a wide range of safety control architectures, from simple analog circuits to advanced Industry 4.0 digital systems.

Compact Single-Body Design

The MDC Series is designed as a compact single-body valve — in contrast to modular multi-component assemblies — simplifying installation and reducing the number of pneumatic connections required. The body size options (1/2 and 1) accommodate different flow requirements, while NPT port sizing ensures compatibility with standard pneumatic system plumbing.

Technical Specifications

Safety Category: Category 1 PL c; Category 2 PL C
Safety Integrity Level: SIL 1
DGUV Certificate: HSM XXXX (pending)
Operating Pressure: 36 to 150 psig (2.5 to 10 bar)
Standard Solenoid Voltage: 24 VDC
Body Sizes: 1/2 and 1
Exhaust Port Sizes (NPT): 3/8, 3/4
EEZ-ON® Soft-Start: Available (E models) or without (X models)
Pressure Measuring Device: Analog Gauge (G), Digital Transducer (T), or None (X)
Feedback Signal: External (E) or None
Monitoring: External monitoring required
Communication Options: Available (see product key code)
Flow Media: Filtered compressed air
Product Label: Model number, pressure range, manufacturing date code
Documentation: Declaration of CE Conformity pending; see www.rosscontrols.com

Applications

Safety Exhaust (Dump) Applications

The MDC Series is used as a safety exhaust valve in pneumatic machine safety circuits. When the valve is de-energized (by a safety stop command or fault), it dumps all downstream pressure to atmosphere, rapidly removing pneumatic energy from the hazardous zone. This function is critical in robot cells, automated assembly equipment, pneumatic presses, and any machine where a controlled safety stop requires complete removal of downstream air pressure.

Soft-Start Applications

The MDC Series with EEZ-ON® is used in applications where sudden pressure build-up upon machine restart could cause unexpected actuator motion or equipment damage. Typical soft-start applications include pneumatic cylinder-driven clamps, grippers, presses, and transfer mechanisms where controlled pressure ramp-up is required for both safety and equipment protection.

Safety and Compliance Standards

ISO 13849-1:2015 — Category 1 PL c and Category 2 PL C
IEC 62061:2001 — SIL 1
DGUV Certificate: Pending
Declaration of CE Conformity: Pending; check www.rosscontrols.com for current status
External monitoring required for Category 2 applications
L-O-X® valves are defined as energy isolation devices, NOT emergency stop devices

Installation and Setup Guide

Pre-Installation Checks

Before installation, verify the MDC Series model number matches the application requirements (body size, soft-start option, pressure range, voltage). Blow all air lines clean. Install a 5-micron rated air filter upstream of the MDC valve.

Valve Mounting and Pneumatic Connections

Install the MDC valve according to the flow direction indicated on the product label. Connect Port 1 (inlet) to the filtered supply, Port 2 (outlet) to the machine zone or actuator, and Port 3 (exhaust) to atmosphere via a suitable ROSS silencer. Ensure all NPT connections are properly sealed.

Electrical Connections and Feedback Wiring

Connect the 24 VDC solenoid power and any pressure sensor or transducer signals per the product label and wiring diagrams. Wire feedback signals to the external safety monitoring system (safety PLC or safety relay) as required. Verify all connections before energizing.

EEZ-ON® Adjustment (E Models)

For MDC Series with EEZ-ON® soft-start, adjust the soft-start flow control as needed to achieve the desired pressure ramp rate. Consult the soft-start adjustment charts in the operating instructions for guidance on the relationship between adjustment turns, inlet pressure, and build-up time.

Why Choose ROSS Controls

ROSS Controls has been the innovator behind EEZ-ON® soft-start technology for decades. The MDC Series represents ROSS's commitment to packing maximum functionality into a compact, cost-effective package. With over 100 years of fluid power experience since 1921, ROSS continues to advance the state of the art in pneumatic machine safety. Contact ROSS at 1-800-GET-ROSS or www.rosscontrols.com.

Download This Document

The official MDC Series Valves Operating Instructions (RC-MDC-OI) includes product key identification, schematics, dimensional drawings, and installation guidance for all MDC1 and MDC2 configurations.

Download PDF: https://ross-admin-global-us-east.s3.amazonaws.com/production/uploads/document_language_file/file/5555/MDC_Valves_Operating_Instructions_RC-MDC-OI.pdf

Frequently Asked Questions

Q: What is the difference between MDC1 and MDC2?

A: MDC1 refers to the 1/2 body size configuration and MDC2 refers to the 1 body size configuration of the MDC Series. Both are available with (E) or without (X) the EEZ-ON® soft-start module.

Q: What safety category does the MDC Series achieve?

A: The MDC Series achieves Category 1 PL c and Category 2 PL C per ISO 13849-1:2015, and SIL 1 per IEC 62061:2001.

Q: What is the operating pressure range for the MDC Series?

A: The MDC Series operates at 36 to 150 psig (2.5 to 10 bar), as shown on the product label.

Q: Does the MDC Series require external monitoring?

A: Yes. The MDC Series is designed for use with an external safety monitoring system. The Category 2 PL C rating requires integration with an appropriate safety control architecture.

Q: What communication options are available on the MDC Series?

A: The MDC Series supports analog gauge (G), digital pressure transducer (T), external feedback signal (E), and communication output options as defined by the product key code. See the product label for the installed configuration.

Q: What are the available exhaust port sizes on the MDC Series?

A: MDC Series exhaust port sizes (NPT) include 3/8 and 3/4, selected via the product key code to match system flow requirements.

Q: Is the EEZ-ON® function adjustable on the MDC Series?

A: Yes. For MDC Series E models with EEZ-ON®, the soft-start flow rate is adjustable via a flow control screw. Consult the operating instructions for the flow vs. turns chart at various inlet pressures.

Q: Where can I find the MDC Series Declaration of Conformity?

A: The Declaration of CE Conformity for the MDC Series is pending at time of publication. Check www.rosscontrols.com for the current status of all certifications and declarations.