Mainstream Machine Safety

Whether It's Complex Schemes or Basic Operator Protection Measures, Machine Safety Is a Design Essential

By Control Design Staff

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In our Fall 2011 audience survey on machine safety, we asked questions about the effects — better or worse — that the integration of machine safety and machine automation tasks will most likely have in several key areas.

An increase in operator safety was cited by 83% of respondents, while 16% believed operator safety would decrease. An increase in machine productivity was foreseen by 39%, but nearly 30% expected it to worsen. Some 43% expected increased employee effectiveness, but 33% didn’t think so. A full 78% expected higher installed costs, and 77% expected increases in development time. Increased reliability was expected by 54%, but 30% thought reliability would suffer.

Asked about specific safety components, a hardly surprising 96% have e-stop buttons on their machines, and 75% have gate/door interlocks. Farther down the list, about 55% say they use status indicators/stack tower lights and have some form of operator access control.

Less than half (45%) specify a programmable safety controller or provide visual status of sensors. Some 42% employ safety light curtains and 28% include safety mats.

Schmersal's Stainless Steel IP69K-Rated Sensor

Safe, Not Sorry
BNS40S safety sensor monitors the position of movable safety guards per EN 1088 and EN 60947-5-3 in an IP69K-rated stainless steel housing and concealed mounting. It is cULus-approved and can be used in safety circuits up to PLe/SIL 3/Category 4.
Schmersal
(888) 496-5143
www.schmersalusa.com

Littelfuses' EL731 ac/dc sensitive earth-leakage relay

Leaks Are Dangerous
EL731 ac/dc sensitive earth-leakage relay can detect ground currents in resistance-grounded electrical systems down to 0 Hz to protect variable-frequency drives (VFDs) that operate at low speeds, during which ac current approaches dc. VFDs operating in resistance-grounded electrical systems are growing in popularity because of their ability to reduce arc-flash hazards.
Littlefuse
(773) 628-0706
www.littelfuse.com

ABB Jokab Safety's Food-grade switches

Switch On, Switch Off
Food-grade switches are manufactured using 316 stainless steel, and include mechanical keyed interlock switches, non-contact sensors, explosion-proof sensors and IP69K sensors. The product line includes e-stop rope pull switches and enclosures.
ABB Jokab Safety
(888) 282-2123
www.jokabsafetyna.com

Pepperl+Fuchs' VAS-2A8L-KE4-8SE Programmable Safety Controller

Expandable Safety\
VAS-2A8L-KE4-8SE programmable safety controller with an expansion port provides four redundant safe inputs and two independent safe electronic outputs. It runs on standard 24 Vdc and allows any safe device with dry contacts or electronic safe outputs to be used.
Pepperl+Fuchs
(330) 486-0001
www.pepperl-fuchs.us

Siemens Industry's IM154-8FX PN/DP F failsafe CPU

Safe If It Fails
IM154-8FX PN/DP F failsafe CPU for restricted areas with no space for switchboxes has IP65/67 protection. It has LEDs, online diagnostics and diagnostics alarm. Module data and diagnostics are available via web server.
Siemens Industry
(800) 241-4463
www.usa.siemens.com/industry

Beckhoff Automation's EP1908 EtherCAT Box with TwinSafe technology

Bus Safety
EP1908 EtherCAT Box with TwinSafe technology includes an IP67-rated variant with eight 24 Vdc safety inputs to connect safety sensors via M12 connectors. Inputs can accept OSSD signals from light curtains and laser scanners. Zero speed monitoring via encoder or proximity switch of 0–500 Hz max is possible.
Beckhoff Automation
(952) 890-0000
www.beckhoffautomation.com

Wago's Profisafe Modules With iPar Functionality

iSafety
Profisafe modules with iPar functionality support the automatic download of parameters to the controller via Profisafe-compliant iPar server. Parameters can be set, backed up and documented using Safety-Editor. The modules support tool calling interface (TCI) up to Conformance Class 3, so the Safety-Editor can be integrated into corresponding TCI-compatible engineering systems.
Wago
(800) din-rail
www.wago.us

AutomationDirect's LG5924 Series Dold relays

Solid Dold 
LG5924 Series Dold relays are single-channel, e-stop relays with 24 Vdc, 110 Vac and 230 Vac coil voltages, and with internal positive temperature coefficient resistor short-circuit protection. Output options include either two normally open contacts, or three normally open and one normally closed contact. The normally open contacts are safety contacts. LG5925 Series relays are dual-channel, e-stop/safety gate relays designed for applications with emergency stop buttons and safety gates.
AutomationDirect
(770) 889-7876;
www.automationdirect.com

Rockwell Automation's Guardmaster SC300 hand-detection safety sensor

Hand Signals
Guardmaster SC300 hand-detection safety sensor requires no software to configure and is designed to fulfill SIL 2 per IEC 61508 and PLd per EN ISO 13849. It is a single-image sensing/processing device that detects when an object of a certain resolution blocks the device's view. The machine then shuts off when a hand is detected. Reflective tape is attached to a square or rectangular frame to define detection boundaries to 4.92x4.92 ft.
Rockwell Automation
(414) 382-2000
www.ab.com/safety

Phoenix Contact's SafetyBridge product technology

Safe on Its Own
SafetyBridge product technology distributes safe I/O modules in a network without a fail-safe controller because the modules process the safety function themselves; the standard control system and network are used only as a transport medium. Safeconf software lets users parameterize the safety input and output channels and generate the safety logic, even without programming experience.
Phoenix Contact
(800) 322-3225
www.phoenixcontact.com

Keyence's GL-R Series safety light curtain

Behind the Aluminum Curtain
GL-R Series safety light curtain is built from a 3 mm thick extruded aluminum body with a narrow, 9 mm wide recessed lens surface, sealed to meet IP65 and IP67 ratings. One-line wiring system allows the transmitter to be connected in series directly to the receiver for power and synchronization purposes. Smart features include edge-to-edge detection, built-in muting and blanking, visible indicators, quick disconnect cable options, and monitoring software.
Keyence
(888) 539-3623
www.keyence.com/prglr

 Banner Engineering's 30 mm mount illuminated e-stop pushbutton

Color Change
30 mm mount illuminated e-stop pushbutton has status indication. When the button is pushed, yellow illumination turns to flashing red to alert operators of an emergency stop condition. A steady red indication when a stop condition exists is possible by applying an external signal via the M12 QD connector.
Banner Engineering
(888) 373-6767
www.bannerengineering.com

Omron STI's Software-Based G9SP Programmable Safety Controllers

Standalone and Deliver
G9SP programmable safety controllers have three base models with a range of I/O options, and four types of expansion I/O units are available for hardwired diagnosis or standard signals. They deliver diagnostics and monitoring via Ethernet or serial connection, and support direct connection with non-contact switches and safety mats.
Omron STI
(800) 479-3658
www.sti.com

Moore Industries' STA Safety Trip Alarm

Failsafe Alarm
STA safety trip alarm accepts signal input from transmitters, temperature sensors, resistance and potentiometer devices, and other monitoring and control equipment. It provides three failsafe alarm outputs, and is certified to IEC 61508: Parts 1, 2 and 3 by TÜV Rheinland for single use in Safety Instrumented Systems up to SIL 2.
Moore Industries
(818) 894-7111
www.miinet.com

Tapeswitch's PSSR-2 safety interface controller Have Some Integrity
PSSR-2 safety interface controller integrity monitors safety switch, mat, edge and bumper product with a 6.8 or 8.2 kΩ end-of-the-line resistor at Category 3 SIL 2 PLd, EN 13849. It has a manual and auto reset, three output contacts, force guided relays, and two normally open (safety) and one normally closed (monitor) contacts.
Tapeswitch
(800) 234-8273
www.tapeswitch.com
CD1107_RU_euchner.jpg

Access Control
Light version of Electronic Key System (EKS) is a transponder-based access control that provides parameter assignment for the keys via a programming station on a PC, provides security with an infinite number of key tag combinations (116 byte), and is not affected by magnetics.
Euchner USA
(315) 701-0315
www.euchner-usa.com

B&R Industrial Automation's X20SL8000 SafeLogic controllers

Safety Central
X20SL8000 SafeLogic controllers handle all central tasks within a safety-related application. They support up to 20 safety nodes, and have exchangeable application memory, one Powerlink V2 interface, and a power supply module.
B&R Industrial Automation
(770) 772-0400
www.br-automation.com

Schneider Electric's Remote Racking System

Safe Racking
Remote Racking System (RRS) promotes workplace safety by automatically racking circuit breakers from a distance via a remote control station and customized cord length. An RRS removes the operator from manual contact with the circuit breaker while it is being inserted or removed, an activity during which a significant percentage of arcing faults occur.
Schneider Electric
(888) 778-2733
www.schneider-electric.us

CD1203_RU_patlite.jpg

Sights and Sounds
LKEH Series combines LED light tower with an audible horn integrated into the base, and is offered with pre-installed sounds or with MP3 field-programming capability. Volume is adjustable from zero up to 105 dB at 1 m.
Patlite
(310) 328-3222
www.patlite.com

ASI's Type 4 finger safety light curtains

Count to Five
Type 4 finger safety light curtains have a maximum operating distance of 6 m, controlled heights ranging 150–1800 mm, and 14 mm resolution. They have a 32x37 mm profile with selectable EDM and manual/automatic restart.
ASI
(877) 650-5160
www.asi-ez.com

Electro-Sensors' Electro-Sentry 1

Watch the Dust
Electro-Sentry 1 for grain elevator legs monitors for shaft slowdown, belt misalignment and bearing temperature as part of a dust-explosion prevention program. Control panel shows all sensor values and alarm conditions; one-button push-to-test verifies operation of sensors, set points and alarm output relays; and it includes 13 analog inputs and eight relay outputs. Sensors provide a standard 4–20 mA signal compatible with IS barriers, PLCs, meters and data acquisition systems.
Electro-Sensors
(800) 328-6170
www.electro-sensors.com

Advanced Machine & Engineering's Pneumatic series RLN rod lock

Lock It Down
Pneumatic series RLN rod lock controls over travel, drifting, bouncing and reverse traveling. The piston and wedge locking mechanism is actuated by multiple springs that mechanically lock the rod. The clamp is unlocked when air actuates the piston, compresses the spring and releases the locking device. NFPA-style mounting attachments are available for standalone applications.
Advanced Machine & Engineering
(800) 225-4263
www.ame.com

Standex Electronics' Non-contact proximity alarm

Can’t Touch This
Non-contact proximity alarm combines audio and visual alerts, built around magnetic reed switches that sense without contact. Battery-powered device requires no wires or hookups, and the reed switches retain magnetic sensitivity of 2–4 ampere-turns (AT), typical operating time of 0.2 mss and typical release time of 0.1 ms.
Standex Electronics
(866) standex
www.standexelectronics.com

Ross Controls' Modular L-O-X Air Entry valve Space Saving Lockout
Modular L-O-X Air Entry valve combines three elemental products into one: a filter, a regulator and a lockout valve. It complies with ANSI/PMMI B.155.1-2006 and ANSI B11.GSR standards with its full-size exhaust port and a verification port for visible pressure release indication. Conforming to OSHA lockout requirements, the L-O-X is lockable only in the off position.
Ross Controls
(248) 764-1850
www.rosscontrols.com
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Safety PLC
eloProg programmable safety controller monitors inputs such as photoelectric sensors, light curtains, magnetically operated sensors, e-stop buttons, etc., and lets the user program the function of these inputs using icon-based software to create specific logic to control the safety outputs.
Elobau Sensor Technology
(847) 672-7515
www.elobau-st.com

Eaton's M22 e-stop buttons

Stop It
M22 e-stop buttons have clear color signals with a luminous ring in 45 and 60 mm sizes with or without a key, twist-release, non-illuminated, illuminated with standard LED, or with mechanical switch position display in the center of the actuation element. They are tamper-proof in compliance with EN ISO 13850, and conform to EN 60204 and IEC 60204.
Eaton
(877) 386-2273
www.eaton.com

Electroswitch TD-CSR Time Delay Control Switch Relay

Time to Go
TD-CSR time delay control switch relay provides a means to mitigate arc flash danger in local circuit breaker operation by allowing a manually initiated, time-delayed trip or close. A flashing LED notifies the operator of pending trip or close operation and as a warning to evacuate the arc flash area. To avoid an inadvertent operation, the control pushbuttons must be depressed for four continuous seconds to activate the 10-second delay.
Electroswitch
(781) 335-5200
www.electroswitch.com

CD1107_RU_honeywell.jpg Change Channels
Each channel of Safety Manager Remote Universal Safety IO can be configured individually to a different I/O type. Each module has a capacity of 32 configurable channels, and up to 28 redundant modules can be connected to a Safety Manager using the SIL 3-certified Safety Manager Remote I/O communication network.
Honeywell
(800) 343-0228
www.honeywell.com/ps
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