SOLID STATE RELAYS AND BARRIERS GEMS Relays and Barriers Render Any Non-Voltage Producing Sensor or Switch Intrinsically Safe ► Provide method of eliminating explosive conditions ► Rapid, arc-free response provides positive, non-mechanical operation ► Solid-state reliability assures consistent performance ► Low-power switching; a few milliamps of current controls high-power loads ► Completely encapsulated construction Units are impervious to dust, moisture or foreign material They are tamper-proof and shock- and vibration-resistant ► Modular housings for easier installation ► Exceptionally long, trouble-free service life Intrinsic Safety and its Advantages. Instrument Society of American Specification ISA-RP12.2 Defining Intrinsically Safe Equipment: "Intrinsically safe equipment and wiring is equipment and wiring which is incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture in its most ignited concentration. Intrinsically safe terminations and wiring may be brought into any hazardous location of any Group classification for which it is accepted without requiring explosion-proof housing or other means of protection." To be certified "intrinsically safe," a device or circuit must be so designed that no two simultaneous failures can cause an explosion. Intrinsically safe systems are more dependable. The I.S. circuit must function reliably per specifications, with no explosions, during and after cycling through a number of operations. The units can also be installed more conveniently. Since no explosion is possible, no explosion-proof conduit or enclosures of any kind are needed in the hazardous area. Maintenance can be performed immediately as needed. And, intrinsically safe systems are more economical. Costly enclosures with their mounting requirements are unnecessary. No purging is required, thereby eliminating blowers, pressure switches, timers and relays. SAFE-PAK® RELAYS: These intrinsically safe units amplify sensor load-handling capabilities in a wide diversity of AC and DC control switching applications. Zener Barriers: These passive, energy-limiting devices, provide intrinsically safe DC outputs for a variety of sensors such as level and flow switches.. .level indicating transducers and transmitters.. .and many others. The maximum energy possible at the switch terminals of the SAFE-PAK and Zener Barriers is far below the explosive point of the most volatile surrounding gas conditions. The type of non-voltage- producing switch or sensor best suited for the application can be utilized, since the entire switching circuit is rendered intrinsically safe by the SAFE-PAK or Zener Barrier. As the switching circuit is low voltage, there is no shock hazard to operating or maintenance personnel. Visit www.GemsSensors.com for most current information.

. Sensors & Controls Typical Applications Switches Located in Hazardous Areas Important points to remember when selecting Zener Barriers and Safe Pak® : • The maximum input voltage rating of the barrier must be higher than your power supply. (i.e., a 24 VDC supply would require a 30 V barrier.) • Make sure the barrier is rated for your hazardous area class, Intrinsic Safety Approvals - Safe-Pak® Relays and Zener Barriers 1. Certified intrinsically safe under MSHA certification No. 1662 for use on permissible equipment. 2. Zener Barrier models, Part Numbers 54801, 54803, 54805, 54806; Programmable...

SAFE-PAK and Zener Barrier units are installed in a safe area and connected to the sensor in a hazardous location...no explosion-proof or protective housings of any kind are needed. Units install singly, in any position...or can be grouped on a common, earth-grounded plate with mounting tabs to provide electrical grounding. No. 6-32 threaded electrical terminals are conveniently placed atop the unit housings. Barriers and relays may be grouped on a common, earth-grounded mounting plate. Intrinsically safe sensor wiring must be separated from non-intrinsically-safe input wiring in separate conduits...

. Sensors & Controls Intrinsically SAFE-PAK® Relays Amplify Sensor Load-Handling Capabilities Costly explosion-proof enclosures with their mounting requirements are unnecessary. SAFE-PAK: Less than 100 microamps at 9 VDC actuates the unit to control loads to 5A at 120 VAC. Resistive (up to 100,000Q ) or short-circuiting sensors operate the Low Sensitivity SAFE-PAK: Sensor closures up to 1000Q resistance control resistive See table on Page L-2 for specific approval information Select Part Number based on Relay Style, Operating Voltage and Switch Operation required. 3. All AC voltage and current...

3 RED N.O. DRY OR N.C. DRY 2 1 RESISTOR (–) 3 BLACK 2 1 FUSE* DC POWER SUPPLY ANNUNC. (+) 2 CONDUCTOR CABLE intrinsically safe relays SIGNAL RETURN BARRIER Typical Wiring Diagrams HAZARDOUS AREA NON-HAZARDOUS AREA FUSE BLACK RED LOAD N.O. DRY OR N.C. DRY HOT VAC NEUTRAL VAC FUSE SAFE-PAK SAFE-PAK, Part Numbers 25872, 25873, 64101 or 144600 with sensor switch in hazardous location. Transient Protection for SAFE-PAK (AC Loads) Use a properly sized metal oxide varistor (MOV) as shown below. HAZARDOUS AREA NON-HAZARDOUS AREA BLACK HOT VAC NEUTRAL VAC RED N.O. DRY OR N.C. DRY SAFE-PAK LOAD ELECTRONIC...

. Sensors & Controls Define Switching Mode Anytime With Programmable SAFE-PAK® Relays Provide normally open (N.O.), normally closed (N.C.) or latching output with variable time delays ► Designed for use with switches or sensors monitoring flow, ► They render non-voltage-producing sensors intrinsically safe for operation in potentially hazardous areas ► Streamlined housing suited for group-mounting on a common earth-grounded plate for multiple installation ► UL recognized, FM, CSA and evaluated by MSHA Operations such as normally open, normally closed or latching are programmed into these versatile...