DM2® Series C Explosion Proof Control Reliable Double Valves Installation & Operating Instructions

Overview

ROSS Controls, founded in 1921 with over 100 years of leadership in fluid power, offers the DM2® Series C Explosion Proof Control Reliable Double Valves as high-integrity pneumatic safety valves for Category 3 and 4 applications in hazardous classified environments. These dual poppet, base-mounted valves combine the dynamic monitoring and inherent lockout capability of the DM2® design with explosion-proof solenoid enclosures rated to IP65 (IEC 60529) for use in classified electrical hazardous locations.

The DM2® Series C uses three solenoids — two main pilot solenoids and one reset solenoid — all rated for continuous duty. The internal monitoring system locks out the valve if either main valve element fails to shift within approximately 125 milliseconds of the other. When locked out, the fault is indicated by the built-in pressure switch status indicator and audible exhaust, and the valve will not resume operation until it is deliberately reset. This design is completely self-contained and does not require an external monitoring system.

IMPORTANT: The DM2® Series C is expressly NOT intended for use in press clutch/brake applications. ROSS produces the DM2® Series D and other double valve configurations specifically for press clutch/brake use. For technical support, call 1-800-GET-ROSS or visit www.rosscontrols.com.

Key Features

Category 4 PL e Safety Performance with 125 ms Monitoring Window

The DM2® Series C achieves Category 4, Performance Level e functional safety as defined by ISO 13849-1. The internal monitoring system detects asynchronous movement of the two independent valve elements within a 125-millisecond window using restricting orifices and timing chambers in the pilot air circuit. B10D is 20,000,000 operations; PFHD is 7.71×10⁻⁹; MTTFD is 301.9 (nop: 662,400). These safety data values enable the valve to be used in the highest-demand safety function applications (excluding press clutch/brake).

Explosion-Proof IP65 Solenoid Enclosures

All three solenoids (two main + one reset) conform to VDE 0580 and carry an IP65 explosion-proof enclosure rating per DIN 400 50 and IEC 60529. Standard voltages are 24 V DC (4.6 W) and 120 V AC 60 Hz (6.8 VA). The electrical connection uses three-wired end sleeve connectors for strands with 1/2-NPT thread for cable conduit, providing robust cable management in industrial hazardous environments.

Anti-Tie-Down Reset Control

The DM2® Series C incorporates an anti-tie-down feature that requires both main valve solenoids to be de-energized during reset. This prevents the possibility of unintended pressure output when the valve is reset after a lockout. A minimum 200 ms delay is required between removing power from the reset solenoid and applying power to the main solenoids. The reset solenoid is 3/2 normally closed, and the reset signal must be momentary.

Technical Specifications

Construction: Dual poppet
Mounting Type: Base mounted
Pilot Solenoids: According to VDE 0580; IP65 (DIN 400 50, IEC 60529)
Number of Solenoids: Three (two main + one reset), rated for continuous duty
Standard Voltages: 24 V DC (4.6 W) and 120 V AC 60 Hz (6.8 VA)
Enclosure Rating: IP65, IEC 60529
Electrical Connection: Three-wired end sleeve, 1/2-NPT cable conduit thread
Ambient Temperature: 15° to 122°F (-10° to 50°C)
Media Temperature: 40° to 175°F (4° to 80°C)
Flow Media: Filtered, lubricated or unlubricated mineral oils per DIN 51519, viscosity classes 32-46
Inlet Pressure: 30 to 120 psig (2 to 8 bar)
Pressure Switch (Status Indicator) Rating: 1 amp at 250 V AC, SPDT
Pressure Switch Enclosure Rating: IP66
Monitoring: Dynamic, cyclic, internal; memory lockout requires deliberate reset after fault
Monitoring Discordance Window: Approximately 125 milliseconds
Functional Safety Data: Category 4 PL e; B10D: 20,000,000; PFHD: 7.71×10⁻⁹; MTTFD: 301.9 (nop: 662,400)
Certifications: CE Marked, DGUV Test, CSA/UL, TSSA (for appropriately tested valves)
Mounting Orientation: Preferably horizontal (valve on top of base) or vertical with pilot solenoids on top
Basic Sizes: 4, 12, and 30
Reset Signal: Momentary, 200 ms minimum recommended
Anti-Tie-Down: Both main solenoids must be de-energized during reset

Applications

Hazardous Classified Industrial Environments

The DM2® Series C is designed for use in environments where explosive atmospheres may be present — chemical processing facilities, paint booths, solvent handling areas, grain elevators, and petrochemical plants where the explosion-proof IP65 solenoid rating is required by the National Electrical Code, ATEX directive, or equivalent authority having jurisdiction. The valve provides Category 4 PL e pneumatic safety control in these demanding environments.

Category 3 and 4 Machine Safety Applications

For pneumatic machinery requiring Category 3 or 4 safety-rated pneumatic control (excluding press clutch/brake), the DM2® Series C provides a self-contained solution. The dual-channel solenoid control, internal monitoring, and automatic lockout on discordant signals reduce complexity in the machine safety circuit and ensure reliable fault detection. The valve integrates with safety PLCs and safety relays via the built-in pressure switch status indicator.

Safety and Compliance Standards

Pneumatic equipment installation and service must be performed by trained and qualified personnel. Complete the mandatory lockout test procedure (test steps A through F) after installation and after any repair before returning to normal operation. Observe operating signal timing: dual-channel concurrent solenoid actuation with discordance less than 25 ms. Turning off supply pressure while the valve is energized will result in a fault requiring reset. Contact ROSS Technical Services at 1-888-TEK-ROSS (835-7677) for questions about installation or certification compliance.

Installation and Setup Guide

Pre-Installation Checks

Step 1: Blow air lines clean. Install 5-micron rated filter on inlet line.
Step 2: Mount base on valve manifold; install pipe with sealant (not tape) engaging one turn, tighten.
Step 3: Blow piping clean after installing pipe into base ports before mounting valve onto base.
Step 4: Connect electrical supply matching voltage and hertz ratings on pilot housing.
Step 5: Perform the mandatory lockout test (steps A-F): energize both solenoids, de-energize one → expect lockout; repeat for other solenoid; then reset and verify normal operation.
Step 6: Verify reset timing: 200 ms minimum delay between removing reset solenoid power and applying main solenoid power.
Step 7: Confirm status indicator (pressure switch) signal to machine safety controls.

Why Choose ROSS Controls

ROSS Controls, founded in 1921 with over 100 years of leadership in fluid power, has been the global leader in control-reliable pneumatic double valve technology since introducing the DM2® design. ROSS DM2® Series C valves carry CE, DGUV, CSA/UL, and TSSA certifications, providing the broadest international compliance coverage available. Contact ROSS at 1-800-GET-ROSS or www.rosscontrols.com.

Download This Document

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Frequently Asked Questions

Q: Can the DM2® Series C be used for press clutch/brake applications?

A: No. The DM2® Series C is expressly not intended for press clutch/brake applications. Use DM2® Series D or other ROSS press-specific double valves for those applications.

Q: What is the functional safety rating?

A: Category 4, Performance Level e (ISO 13849-1); PFHD: 7.71×10⁻⁹; B10D: 20,000,000; MTTFD: 301.9.

Q: What is the inlet pressure range?

A: 30 to 120 psig (2 to 8 bar).

Q: What voltages are available?

A: Standard: 24 V DC (4.6 W) and 120 V AC 60 Hz (6.8 VA).

Q: What is the enclosure rating?

A: IP65 per IEC 60529 for solenoids; IP66 for the pressure switch status indicator.

Q: What happens when the valve detects a fault?

A: The valve locks out, exhausting pilot supply air to prevent further operation. The pressure switch status indicator signals the fault to machine controls. The valve remains locked out until deliberately reset.

Q: What does the anti-tie-down feature do?

A: It requires both main solenoids to be de-energized during reset, preventing unintended pressure output when the valve is reset after a lockout.

Q: What is the monitoring window for discordant valve element movement?

A: Approximately 125 milliseconds. If either element fails to shift fully within 125 ms of the other, the valve locks out.