When loads, such as valves or motors, cannot be driven directly by a safety PLC or by an emergency push button, an interposing relay becomes a necessity. As an example, when the power required to switch the load is greater than what can be provided by the PLC or when multiple contacts are required to be driven by the same signal, the use of a relay is a must.
In today’s high integrity applications a standard relay is no longer acceptable. Whether it is for an ESD, F&G, BMS or for any other critical application, a Safety (SIL 3) Relay must be used.
GM International SIL 3 Relays are available in various contact configurations and ratings to cover the majority of applications; they are available with standard DC as well as with AC coils.
Typical applications are shutdown or relief valves control, Fire & Gas valve control, Turbine shut down, AC/DC motors control center, etc.
For each application the specific Safety Function must be determined to select the correct Safety Relay. The Safety Function controls the operating condition of the SIF, therefore of the Safety Relay.
By “NE Relay Coil” we mean a High condition (power on) at the relay coil terminals and by “ND Relay Coil” we mean the exact opposite, a Low condition (power off). NC or NO Relay Contacts determine whether power is available to the load under normal operating conditions or not; with NC contacts the load is Normally Energized and with NO contacts the load is Normally De-Energized.
The Safety Function is to revert the above operating conditions. For example, with NE relay coil and NC relay contacts, DTS Safety Function is to disconnect power to the load by removing power at the relay coil (From High to Low condition); This is the most typical SIL 3 relay function for a NE Load. Or, with a NE relay coil and NO relay contacts, ETS Safety Function is to power-on load by removing power at the relay coil (From High to Low condition).
Other aspects in selecting the safety relay are: the load’s contacts rating; the number of contacts required to be driven by the same control signal; if a single line or both lines of the load must be switched ON or OFF.
For each GMI Safety Relay, a data sheet containing schematics of all possible applications, as well as coil and contacts rating, is available.
SIL-Rated Safety Relays and Informative Safety Manual
SIL Manual: Safety Instrumented System (3rd edition) is now available.
G.M International’s years of experience in safety and electronics has lead to the development of this comprehensive manual on IEC61508 and IEC 61511.
The first two editions have already been of great benefit to engineers, maintenance personnel and whoever wishes to approach the concept of functional safety.
Would you like a paper or electronic copy? Let us know by emailing sales@exloc.com.
High channel density result from innovative circuit design using advanced surface mount components.
Plug-in screw terminal blocks to secure termination up to 2.5 mm2
35 mm (Top Hat) DIN-Rail
22.5 mm wide DIN-Rail mounting modules.
High channel density result from innovative circuit design using advanced surface mount components.
Plug-in screw terminal blocks to secure termination up to 2.5 mm2
35 mm (Top Hat) DIN-Rail
High packing density. Ultra slim 2 channels 12 mm wide.
Switching of Safety-Related circuits demands the use of specific SIL certified Relay Output modules, capable of delivering the highest grade of availability and functional safety.
These units are so much more than just a relay; they not only perform the desired safety function, but also provide full Load & Line Internal Diagnostics: load voltage and current, load resistance (patented), leakage from load to earth, coil integrity and internal faults. Moreover, MODBUS communication allows the units to be remotely interrogated and configured.
Hardware is SIL 3 certified, while diagnostic functions are now also SIL 2 certified by TUV: they remain two independent features, which can be used separately or together.
For installation in Zone 2 / Div. 2 Hazardous location. All models are ATEX, IECEx and SIL certified.
Switching of Safety-Related circuits demands the use of specific SIL certified Relay Output modules, capable of delivering the highest grade of availability and functional safety.
These units are so much more than just a relay; they not only perform the desired safety function, but also provide full Load & Line Internal Diagnostics: load voltage and current, load resistance (patented), leakage from load to earth, coil integrity and internal faults. Moreover, MODBUS communication allows the units to be remotely interrogated and configured.
Hardware is SIL 3 certified, while diagnostic functions are now also SIL 2 certified by TUV: they remain two independent features, which can be used separately or together.
For installation in Zone 2 / Div. 2 Hazardous location. All models are ATEX, IECEx and SIL certified.
Exloc Instruments, Inc., is a one-stop-shop for instruments and electrical equipment for hazardous and classified locations.
15584 Summit Park, Suite 303
Montgomery, TX 77356
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