- What are the physical characteristics of a safety mat?
- A safety mat consists of two conductive plates that are held apart by non-conductive compressible separators. When the mat is activated the non-conductive separator discs compress into their recess allowing the two plates to make contact giving overall sensitivity to the mat surface.
- The surface of the safety mat is heavy-duty ribbed vinyl with a crosshatch ribbing for the maximum in anti-slip design. The mat is completely sealed and meets European Rating (IP-67) and it provides excellent protection from most chemicals and liquids. Washdowns are no problem.
- Minimum weight with assured detection 35KG.
- Maximum detection zone: 100 square meters for multiple mat systems.
- 4 wire "No Dead Zone" construction.
- 10-Ton forklift truck capacity.
- What is a safety mat system?
A safety mat system is comprised of a safety mat or multiple mats and must be connected to a "Control Reliable" safety mat controller. The controller must employ redundant positive-guided relay outputs. The mat and the controller must be tested and approved as a system to meet European Standard EN-1760-1 and Safety Category 3.
- What standards apply for safety mat systems?
- United States
ANSI-B11.19 - 1990
ANSI/RIA-1506 - 1999
- European Union
Class C Standards - Machine Specific
- Nelsa safety mat systems are UL, CSA and
- Approved to Safety Category 3.
- What are the necessary features for safety mat systems?
- Complete coverage of hazardous area.
- Mat must be permanently affixed to the floor.
- Ramp trim to prevent tripping is required.
- "No Dead Zones".
- Remember safety distance calculation.
- Four (4)-wire construction is required.
- Safety mat must be used with a "control reliable" safety mat controller. Response time shall be specified on the controller. The maximum response time must be less than 100ms over the system operating temperature range.
- Mat must have a minimum object sensitivity, which detects 30-kg (66-lb.) weight on an 80-mm (3.125-inch) diameter circular disk anywhere on the mat sensing surface.
- Safety mat system shall be installed and arranged such that the reset of the safety function requires removal of the obstruction from the sensing surface followed by a separate and deliberate action outside of the sensing surface, when used as the sole means of safeguarding.
- The safety mat system must provide a means for a readily observable indication that the device is operating.
- Safety Distance Calculation
The minimum distance calculated is the minimum horizontal distance from the outer edge of the Eurozone safety mat detection zone to the nearest part of the hazard.
The European prEN-999 formula for floor mounted safety mats is:
S = (1600 x T) + 1200mm
S is the minimum safety distance is millimeters.
The factor of 1600 is based on the standard assumption of 1600mm/s as the approach speed.
T is the overall stopping time in seconds.
The added 1200mm take into account stride length and arm reach. The overall stopping time T is made up of two parts: T = t1 + t2
(t1) is the maximum time between actuation of the sensing function and the output signal switching devices being in the OFF state. For the Eurozone, t1 = 35mS
(t2) is the response time of the machine i.e. the time required to stop the machine of remove the risks after receiving the output from the Eurozone safety mat.
The response time of the machine used is the calculations needs to be the worst case time. Some machines have inconsistent response times, which are dependent upon mode of operation, nature of the workpiece and point in the operating cycle at which stopping is initiated. An allowance should be made for wear in brakes etc., if this can affect the response time. An allowance for further delays in the machine control system may be required in some circumstances.
In this example the Nelsa Eurozone is being used with a machine whose worst case response time has been measured as 0.485 seconds.
Using the formula above,
T = t1 +t2
= 35mS + 485mS
= 520mS = 0.520S
S = (1600 x 0.520) + 1200mm
=832 + 1200mm = 2032
Safety mats will be required from 2032mm right up to the edge of the machine baseplate.
- Product Specifications and Ordering Information for Nelsa Safety Mat Systems.
- Size and number of mats required:
- NEZ-1010 - Eurozone Mat 500x500mm
- NEZ-1030 - Eurozone Mat 500x1500mm
- NEZ-1510 - Eurozone Mat 750x500mm
- NEZ-1515 - Eurozone Mat 750x750mm
- NEZ-1530 - Eurozone Mat 750x1500mm
- NEZ-2010 - Eurozone Mat 1000x500mm
- NEZ-2015 - Eurozone Mat 1000x750mm
- NEZ-2020 - Eurozone Mat 1000x1000mm
- NEZ-2025 - Eurozone Mat 1000x1250mm
- NEZ-2030 - Eurozone Mat 1000 x 1500mm
Note: Special Sizes are available. Please contact Safety-Direct for additional information and pricing.
Safety mat controller required:
- NEZ-4000/P - Polycarbonate Eurozone Enclosure
- NEZ-4000/S - Steel Eurozone Enclosure
- NEZ-4000/D - Din Rail Mount Eurozone Enclosure
Safety mat trim and accessories required:
- NEZ-3010 - Trim – Perimeter (aluminum)
- NEZ-3020 - Trim – Active Joining/Uniting (PVC)
- NEZ-3011 - Trim – Perimeter with cable channel (aluminum)
- NEZ-3030 - Wire Guide (vinyl)
- NEZ-3012 - External Corner Perimeter Trim (aluminum)
- NEZ-3013 - Internal Corner Perimeter Trim (aluminum)
- NEZ-3010-M – Trim – Perimeter (aluminum), cut and mitered
Provided the floor is reasonably flat, clean and free from debris, installation is simple and economical. Lay the mats on the floor, with the uniting trim between the mats. Ensure lead wires from the mat are located conveniently to enable interconnection. Connect all mats together using the connectors supplied and lay wires around the perimeter of the mat area. Place the surface trim around the perimeter of the area, ensuring that none of the wires are trapped, and that the trim is notched to allow the final wires to exit. Drill the floor and insert suitable hardware to secure the trim.
Interconnection of the mats to the controller enclosure is equally simple as only four wires exit the whole system and a minimum amount of technical expertise is required. Simple, easy to understand installation.
Nelsa Eurozone Safety Mat Facts:
- Standard Eurozone Safety Mat lead length is 4.5 meters.
- Standard Eurozone Safety Mat lead wire is AWG 18/2.
- Maximum lead and interconnection wire length is 200 meters.
- Weight of Eurozone Safety Mats is 4.33 pounds per square foot.
- Mat thickness is 9/16".
- Standard Eurozone Safety Mat Controllers will accept up to 100 square meters of mat sensing surface, providing that lead and interconnect wires do not exceed 200 meters.
- Environmental protection: IP66/IP67 - dust sealed, jet sealed, temporary immersion proof.
- Mechanical Operations: 1,000,000
- Humidity: 0 - 100% RH
Nelsa Eurozone Control Unit Facts:
- Controllers can be auto or manual reset.
- Response time (mat pressed to safety output contacts open): 35mS.
- Environmental protections: IP-65.
- Impulse withstand voltage: 2500V.
- Contamination level: III.
- Minimum switched current/voltage: 10mA/10V
- Power Supply: 110V/230VAC or 24VAC/DC
- Power consumption: <9 VA 6W.
- Relay outputs: 2 x independent voltage free N/O safety contacts – Fuse externally. Maximum external output fuse-: 5A (quick acting).
- Maximum switched DC current: 2A/30VDC/60W.
- Outputs: Remote reset/indicator: 24VDC / 0.24W.
- LED Indicators(4): Auto Reset Mode, Power, Manual Reset Mode, Machine Enable
Download Safety Relay Manual - Schleicher (779 KB)
Download Safety Relay Applications - Schleicher (692 KB)
- What is a safety relay module?
A safety relay module is a safety component that operates with an Emergency Stop Button (E-Stop), or other safety device (Gate Switch, Safety Mat, Two-Hand Control, etc.), to insure that when a safety device is activated by personnel, the electrical supply to the process is disconnected. As an example:
- A safety relay has been wired with three (3) emergency stops and if an E-Stop is activated by an employee due to an emergency situation, the safety relay insures that the motor to the control system brings the machine to a safe stop even if there is a welded contact.
- An operator steps on a safety mat and the mat senses the presence of the individual and insures that the machine will come to an immediate stop.
- What are the types of safety relay modules?
- Basic E-Stop Safety Relay Module
- Safety Gate/Safety Switch Safety Relay Module
- Safety Mat/Bumper/Edge Safety Relay Module
- Safety Two-Hand Anti-tiedown Safety Relay Module
- Light Beam Safety Relay Module
- Valve Position Safety Relay Module
- Proximity Sensor Safety Relay Module
- Expansion Safety Relay Module
- Why use Emergency Stop Safety Relays?
Schleicher has a complete range of safety relay modules. These electro-mechanical safety relay modules with force-guided contacts are now being used for a wide variety of applications. Uses include the monitoring of E-Stops, Gate Switches, Two-Hand Anti-Tiedown Controls, Safety Mats, Bumpers and Edges, to name a few. The safety relay provides self-checking during each on/off machine cycle and cross-monitoring to ensure that no short circuits occur within the system. They offer the security required by both American and European Safety Standards. All Schleicher Safety Relay Modules are UL, CSA and CE Approved.
- What are the applications for Safety Relay Modules?
- Measurement and Control Systems
- Emergency Stop Devices
- Safety Light Barriers
- Light Curtains
- Thick Film Measuring Devices
- Sensor Evaluating Devices
- Testing Machines
- Stop Indicators
- Protective Gate Controls
- Press and Stamping Controls
- Two-Hand Operating Devices
- Extrusion Machines
- Robot Controls
- Crane Controls
- Knitting Machines
- Letter Sorting Machines
- Revolving Door Monitoring
- Laser Cutting Machines
- Positioning Systems
- Printing Machines
- Sheet Metal Working Machines
- Welding Presses
- Safety Mat Controllers
- Light Curtain Controllers
- Robot Controllers
- Garbage Removal Cars
- Burner Controls
- Operator Control Panels
- Stop Indicators
- Protection Gate Controls
Building Automation Systems
- Safety Mat Controllers
- Signaling Systems
- Track Interlock Controls
- Wheel Counting Devices
- Door Controls
- Brake Controls
- Road Signals for Construction
- Dead Man's Switch Controls
- Operator-less Trains
- Lift Controls
- Elevator Controls
- Escalator Controls
Office Automation Systems
- Infant Breathing Apparatuses
What is redundant circuitry?
Redundancy consists of two or more parallel relay circuits which work together electrically with the control function. The tripping contacts of the relays are connected in series to ensure that the Emergency Stop (E-Stop) circuit will disconnect the power even if one of the relays has failed.
What are positive-guided, force-guided or captive contacts?
Positive-guided, force-guided or captive contacts are all different terms for a relay or contactor, which is mechanically forced to operate in a certain fashion. This is achieved by means of a mechanical drive bar, which forces the contacts to behave in the desired manner. Each contact in its open position must maintain a minimum clearance between the contact faces.
European Standard EN-50205 - 3.1 states:
The contacts in a contact set (at least 1 N.O. contact and 1 N.C. contact) must be mechanically linked together, so that it is impossible for N.O. and N.C. contacts to be closed at the same time. Also, 0.5mm minimum air gap between open contacts must be present over the whole service life, even in case of failure. The forced-guidance must always be preserved, even when a relay component fails to function correctly.
Classes of forced-guidance:
Class A - Relays with mutually linked contacts which form a forced-guidance contact set. A contact is considered to be open when its contact gap is >0.5mm.
Class B – Relays with individually linked contacts, which contain a number of forced-guided contacts and other non-forced-guided contacts or changeover contacts.
Only N.O. and N.C. contacts can be used as forced-guided contacts. Contacts, which are designed as changeover contacts, must be used as either N.O. or N.C. contacts in the sense of forced-guided operation. If the unused contact is connected to a non-safety circuit, then circuit analyses must be performed to ensure that this will not impair safety.
Forced-guidance according to EN-50205 states a failure is tolerated if the forced-guidance feature exists, i.e., no contacts of opposite mode are closed simultaneously (which is a predetermined behavior of each contact within the contact set).
The advantages of electromechanical forced-guided relays:
What information must be provided to ensure the selection of the correct safety relay for the application?
- Ensured physical separation - separation of coil and contact.
- Clearly defined switching behavior - the relay contacts behave consistently over the life of the relay.
- Overload capacity - relay coils can withstand short time current overloads up to 15 times the rated current (as opposed to semiconductors, which cannot be overloaded in this matter).
- Variable Function - Universal Application - Relay contacts can switch alternating, direct, or HF currents. There are polarized and non-polarized versions, various voltage ranges and various contact configurations.
- Insensitive to environmental influence - less sensitive to electrical and climatic interference than semiconductors.
- Long service life - rated for 100,000 electrical and 1,000,000 mechanical operations.
- Economical - relays do not need a highly regulated power supply or coil-operating voltage. In addition, several contacts can be switched simultaneously on one relay.
- Safety Category of the Machine - Requires Risk Assessment.
- Operating voltage of machine. 24/120/230 VAC, 24VDC.
- Number of safety outputs required for the application.
- Type of Relay Required: E-Stop, Safety Gate, Two-Hand, etc.
- Housing Size: 22.5mm, 45mm or 90mm.
- Stop Category Required: 0 (Immediate) or 1 (Controlled).
- If Stop Category 1 - Time Required.
- Will relay be wired as "Single Channel".
- Will relay be wired as "Dual Channel".
- Is "Cross-Monitoring" required.
- Is "Monitoring of the Reset Switch" required.
Download Safety Switch Manual - Schmersal
Man-Machine Safeguarding Principles & Practices
- Why should machine guard interlocks be "tamper resistant?
Safety professionals recognize that, in many factories, workers often override or bypass safeguards intended to protect them from injury. Reported motivation includes real or perceived inconvenience, production incentives, familiarity with the equipment, or simply the challenge presented by the presence of the safeguard to be defeated.
Consequently, manufacturers are increasingly recognizing the need for, and their obligation to provide, safety interlocks which are not easily defeated/bypassed by the operator or maintenance personnel
Additionally, safety standards-making groups encourage use of interlocks, which are not easily defeated using simple, readily-available means (such as a paper clip, tape, rubber band, piece of rope, screwdriver, etc.).
For example, the National Standards Institute's (ANSI) B11.19 1990, Reference Standard for Safeguarding Machine Tools specifically requires:
- Barrier guards that protect against unauthorized adjustment or circumvention.
- Interlock devices that are not easily bypassed.
- Reduced liability.
With the growing number of product liability cases, companies are recognizing the benefits of designing safety circuits with interlock devices that are difficult to defeat. To further reduce their liability exposure, firms are selecting only those devices that have been tested and certified for use in safety applications by a recognized, independent third-party agency.
Manufacturers are encouraged to surpass safety design expectations. As cited in a recent DESIGN NEWS seminar entitled 90''s, jurors expect companies to go beyond mere compliance. They give greater benefit to firms who have designed their products with the latest state-of-the-art machine guarding safety devices.
What is meant by the term "difficult to defeat" when related to safety interlock switches in safety standards such as ANSI B11.19, ANSI B11.20, ANSI-RIA R1506, OSHA 1910.212, et al?
"Difficult to defeat" is a subjective term related to workers' propensity to override or bypass safety devices intended to protect them from injury. Colloquially it means that the relevant devices or systems cannot be defeated or bypassed using readily available means (such as a piece of wire, tape, simple hand tool, etc.). It implies the basic safety interlock switch design serves as a deterrent to easily overriding or bypassing its intended function.
How is this requirement ("difficult to defeat") being addressed by safety interlock switch manufacturers?
Safety interlock switch manufacturers are addressing this requirement by:
What are "positive-break" safety interlocks
- Designing two-piece keyed interlocks which feature a geometrically-unique actuating key and associated operating mechanism which function together to deter "bypassing".
- Designing "coded-magnet" sensors whose multiple reed contacts can only be actuated in the presence of a matched magnetic field array.
- Encouraging "positive-mode" mounting of single-piece interlock switches.
"Positive-break" safety interlocks are electromechanical switches designed with normally-closed (NC) electrical contacts which, upon switch actuation, are forced to open by a non-resilient mechanical drive mechanism. (Spring actuators are not considered positive-break mechanisms.)
The actuator key is typically mounted to a movable guard – such as an access door, protective grating, equipment hood, or plexiglass safety cover. When the guard is closed, the actuator mates with the electromechanical switching mechanism. Upon opening of the movable guard, the actuator key mechanically rotates a cam mechanism – forcing the NC electrical contacts to open the safety circuit.
For machine applications with residual motion after shut-down, key actuated interlocks are available with a solenoid latch – which, in conjunction with a time-delay, motion detector, position sensor or other machinery status monitor, can delay access to hazardous areas until safe conditions exist.
Are conventional electromechanical limit switches designed with "positive-break" contacts?
Conventional limit switches are typically designed to use a spring force to open normally-closed electrical contacts. Such designs are subject to two potential failure modes:
When "actuated" either situation may result in an unsafe condition due to failure to open normally-closed contacts. Consequently, such designs are not certified or recognized as suitable for safety applications.
- Spring failure.
- Inability of the spring force to overcome "stuck" or "welded" contacts.
Schmersal offers several "limit" switches designed with "positive-break" contacts in both snap-acting and slow-action models for use in safety applications.
How can I recognize "positive-break" safety interlock switches?
Devices which feature "positive-break" design carry the following internationally-recognized (IEC) safety symbol: (this symbol is an arrow in the center of a circle). These designs meet the international requirements established for such safety interlock switches.
What is meant by a "positive linkage" switch actuator, and why is it recommended for safety applications.
A "positive linkage" switch actuator is designed to eliminate possible slippage between the actuator and it's mounting shaft. Examples if such designs are pinned, square or serrated shafts.
What is "positive-mode" mounting and why is it essential in safety applications?
"Positive-mode" mounting assures that an electro-mechanical safety interlock switch is positively-actuated when equipment or machinery shut-down is desired.
When mounted in the positive-mode, the non-resilient mechanical mechanism which forces the normally-closed (NC) contacts to open is directly driven by the safety guard. In this mounting mode, opening the safety guard physically forces the NC contacts to open when the guard is open.
When mounted in the "negative-mode," the force applied to open the normally-closed (NC) safety circuit contacts is provided by an internal spring. In this mounting mode the NC contacts may not open when the safety guard is "Open." (Here welded/stuck contacts, or failure of the contact-opening spring, may result in exposing the machine operator to a hazardous/unsafe area of the machinery.)
Positive-mode installation is especially important when using single-piece safety interlock switches. This installation mode takes full advantage of the device's "positive-break" design – using the external/force applied by the safety guard to open the NC contacts.
What are the risks of installing single-piece, safety interlock switches in the "negative mode"?
When mounted in the "negative-mode", single-piece safety interlock switches can be easily defeated/circumvented by the operator…often simply by taping down the switch actuator when the safety guard is open.
Under such circumstances the operator or maintenance personnel may be exposed to an unsafe or hazardous condition.
Consequently, where possible, two-piece, key-actuated, tamper-resistant safety interlocks are recommended. These devices are designed to be difficult to defeat, while providing assurance of safety circuit interruption inherent with "positive-break" interlock switch designs.
What are "self-check," "redundancy," and "single-fault tolerance"?
Self-Checking: The performing of periodic self-diagnostics on a safety control circuit to ensure critical individual components are functioning properly. Faults or failures in selected components will result in system shut-down.
Redundancy: In safety applications, redundancy is the duplication of control circuits/components such that if one component/circuit should fail, the other (redundant) component/circuit will still be able to generate a stop signal. When coupled with a "self-checking" feature, a safety circuit component failure within the safety circuit monitoring module or safety relay module will be automatically detected and the machine shut down until the failure is corrected.
Single-Fault Tolerance: A safety circuit is considered to be single-fault tolerant if no foreseeable single fault will prevent normal stopping action from taking place.
Rugged, "fail-to-safe," safety circuit monitoring and control modules (often called safety relay modules) are also available that incorporate the above features to satisfy the "control reliability" requirements of existing domestic and international safety standards.
Are cable-pull switches acceptable for use in E-Stop circuits?
OSHA and the European safety standards permit use of cable-pull switches in E-Stop circuits provided they:
- Operate whether the cable is pulled or goes slack (e.g. breaks or is cut).
- Feature positive-break NC contacts.
- Must be manually reset before the controlled equipment can be restarted.
In addition, European Norm EN418 requires that the switch latch at the same time that the contacts change state.
Are reed switches recommended or acceptable in safety circuits and, if so, under what conditions?
Schmersal offers a variety of cable-pull switches that meet both EN418 and the OSHA guidelines. These are complemented by several safety circuit monitors and safety relay modules designed expressly for use in E-Stop circuits.
Reed switches may be used as interlocks in safety circuits provided:
- They are designed to be actuated by a specific (coded) magnetic-field array matched to the switch's reed-array pattern.
- They are used in combination with a safety relay module or safety circuit monitor capable of periodically checking the integrity and performance of the reed switch contacts.
Coded-magnets are required to actuate the sensor, thus making it difficult for the operator or maintenance personnel to "defeat" or "bypass."
The safety circuit monitor features multiple safety relays with positive-guided contacts, redundant control circuits, and self-diagnostics that check safety system operation. In the event of a component or interconnection wiring failure in the safety circuit, or in the safety circuit monitoring module, the unit will shut down the system in a "safe" state.
Reed switches used without an approved safety circuit monitor or safety relay module do not satisfy safety requirements. Reed switches are susceptible to sticking due to power surges, shock or vibration. Additionally, reed switches tend to fail in the "closed" position. This failure mode cannot be addressed by using a fuse. To ensure reliability of a safety circuit using reed-type switches, use of a safety circuit monitor or safety relay module is required. Depending upon the application, it is also recommended that they feature two independent contacts to permit dual-channel monitoring.
What is meant by "controlled access"?
"Controlled access" generally refers to a movable machine guard that is designed such that it can only be opened under specific conditions. Typically such moveable guards restrict access to an area of a machine which continues to present a hazard to the operator immediately upon the removal of power. In these situations opening of the guard is prevented until the hazardous condition has abated.
This is usually achieved by a solenoid-latching interlock switch controlled by a motion detector, position sensor, time-delay or other machine-status monitor which releases the interlock (allowing the operator to open the guard) only after safe conditions exists.
What is "diverse redundancy," and how does it heighten the reliability of a safety circuit?
"Diverse redundancy" is the use of different types of components and software in the construction of redundant circuits/systems performing the same function. Its use is intended to minimize or eliminate failure of redundant circuits and components due to the same cause ("common-cause" failure). Such designs serve to increase the functional reliability of the safety circuits and systems.
Why are safety interlock switches and safety circuit monitors required?
For machinery builders who export to the European Union, the use of such components designed expressly for machine guarding safety systems is mandated by the requirements of the European Machinery Directive and the need to comply with relevant safety standards. These requirements include:
- Use of interlock switches that feature positive-break normally closed contacts.
- Use of interlock switches or machine guarding position sensors, which are tamper-resistant/difficult to defeat.
- (Where risk level dictates) the need to monitor the integrity of the safety circuit components and its interconnection wiring to ensure the system will function properly when called upon to do so.
For machinery builders selling in the U.S., the use of such components is encouraged by the safety guidelines and standards of the Federal government and several industry standards-making groups including:
As an OEM, what are the benefits of using positive-break and tamper-resistant interlocks in safety applications?
- OSHA (Occupational Health & Safety Administration)
- ANSI (American National Standards Institute)
- UL (Underwriters Laboratories)
- ISA (Instrument Society of America)
- SAE (Society of Automotive Engineers)
Proper selection and installation of safety interlocks which have been tested and certified by an approved, independent safety testing body benefits the equipment manufacturer by:
As an "in-plant user, what are the benefits of using positive-break, and/or tamper-resistant interlocks in safety applications.
- Providing greater protection from injury for machine operators, maintenance personnel, set-up and other user personnel
- Satisfying international safety regulations. a must for U.S. equipment manufacturers who wish to export to the European Economic Community.
- Enhancing product marketability.
- Satisfying safety standards and guidelines against which manufacturer's responsibility, in the event of an injury, is judged.
- Reducing liability risks.
- Minimizing insurance claims/costs.
Proper selection and installation of such safety interlocks, which have been tested and certified by an approved, independent testing body, benefit the in-plant user by:
What are the benefits of using SCHMERSAL safety interlock switches and related controls?
- Providing greater protection from injury for machine operators, maintenance personnel, and other employees.
- Reducing liability risks.
- Minimizing insurance claims/costs.
- Satisfying safety standards and guidelines against which employer responsibility, in the event of an injury is measured.
- Reducing the indirect costs associated with workers injury (e.g. lost production, loss of skilled workers, reduced productivity due to employee's stress, etc.)
While Schmersal is not the only manufacturer of such devices, there are a number of factors, which favor you consideration. These include:
- All SCHMERSAL safety interlocks have been third-party tested and certified to meet relevant directives
- All are CE-compliant.
- Each can be provided with a Declaration of Conformity.
- Each has been designed expressly for safety applications to meet the requirements of ANSI, OSHA and the European Machinery Directive.
- SCHMERSAL's safety interlocks and relatNote: Reprinted from the Schmersal "Passport" Man-Machine Safeguarding Requirements & Techniques. (Fourth Edition)ed controls have been proven in thousands of installations worldwide.
- SCHMERSAL's microprocessor-based Series AES safety circuit monitors feature integrated system diagnostics which, using a visual colored LED display pattern, help identify the type of system fault that has occurred and its location (to minimize down-time).
- SCHMERSAL's safety circuit monitors are easily integrated with their more than 200 "positive-break" interlock switches and coded-magnet sensors to achieve any desired safety level. And, they are also compatible with other manufacturers' safety approved components.
Note: Reprinted from the Schmersal "Passport" Man-Machine Safeguarding Requirements & Techniques. (Fourth Edition)