By Rich Merritt, Senior Technical Editor
or years, MRCs had a strange, illogical fascination with PC-based controls, and annually predicted the coming demise of PLCs. PCs will drive PLCs out of the market, the MRCs would say. All this was much to the amusement of machine builders, process equipment skid builders, end users and system integrators, who were buying PLCs as fast as they could. If PCs were being used for automation and machine controls, it was mostly for HMIs and certain motion control tasks.
PC-based controls barely put a dent in the huge PLC market, and everybody seemed to know it except the market analysts.
Finally, one of the chief proponents of PC-correctness, ARC Advisory Group (www.arcweb.com), appears to have given up. As is its wont, it created another three-letter acronym (TLA) called Programmable Automation Controller (PAC), said PLCs are now PACs, and it is now happy to predict that the sales of PLCs â¦ er, PACs will remain as strong as they always have, at about 4.6% annual growth, reaching $7.5 billion by 2008.
As for industrial computers, Venture Development Corp.(www.vdc-corp.com), predicts that they will continue to grow at 4.4% annually, reaching $537 million in the industrial automation, control and instrumentation market by 2006.
In other words, there is nothing new in the machine control marketing research universe except another TLA.
Some commodity pico and nano-PLCs now cost less than relays, commodity micro PLCs have the capability of the full-size PLCs of 10 years ago, and larger PLCs have become hybrid controllers with PC architectures, networking and web servers. You can buy commodity PLCs in the $100 range, especially with OEM quantity discounts. And if you pay $1,000 for a PLC, you get an outrageously powerful device. Going the other way, you can get a PLC on a chip and embed it in your machine.
No matter what you call them, PLCs are still the most reliable devices on the planet. That, plus their low cost, is why machine builders cling to them with such tenacity.
As you can see in the product round-up that follows, PLC vendors are keeping their products extremely competitive and up-to-date by using the latest hardware, software, and communications technology. This month’s round-up has PLCs and PACs with web servers, fieldbus networks, Linux operating systems, motion control functions and firewalls.
Although some may consider PLCs to be 40-year-old devices, they are as up to date as Kansas City. And, as we all know, “Everything’s up to date in Kansas City” (from the musical, Oklahoma!, which was revived last year on Broadway, with PLCs moving the scenery).
The APC680 industrial PC has Windows XP with real-time expansion, Soft PLC software, slots for PCI and ISA cards, and fastened plug connectors, making it suitable for industrial applications. It is available with a Intel Celeron or Pentium III Tualatin CPU up to 1.26 GHz, and comes with two 100 Mbps Ethernet ports, four USB slots, and four serial interfaces. Flat screen displays can be mounted up to 16.4 ft away.
B&R Industrial Automation: www.br-automation.com
PLC Software Runs Under Linux
Version 4 of SoftPLC control is built on an embedded, real-time version of Linux. Other enhancements include integrated firewall support, encrypted secure communications with the FTP Server, and remote command shell access to run programs, perform diagnostics, and restart the controller. Remote file access lets the software read/write production data to a remote disk.
SoftPLCL: 512/264-8390; www.softplc.com
Redundant Controller Runs Reliably
The PACSystems High Availability controller has two physically independent controllers with an automatic switchover system for redundancy. The controllers have dedicated and redundant links to one another, operate synchronously, and transfer all of the application’s variables, status, and I/O data with each data sweep. Each controller has a Pentium 300 MHz CPU, Cimplicity Machine Edition software, and support for Ethernet, Profibus, DeviceNet and Genius networks.
GE Fanuc: 410/242-0300; www.gefanuc.com
The QTERM-G55 lightweight, handheld terminal has a 320 x 240 pixel, grayscale, graphic LCD display that is viewable in most lighting conditions. Suitable for use in NEMA 4 industrial environments, it has an overmolded rubber boot for shock protection, an ABS polycarbonate plastic case, and a 24 or 40-key membrane steel snap dome keypad. It comes with two serial ports, Ethernet 10Base-T, or a Power-over-Ethernet (IEEE 802.3af) interface.
QSI: 801/466-8770; www.qsicorp.com Industrial Motherboard
The AIMB-744 supports Intel Pentium 4 or Celeron processors operating at speeds up to 3.4/2.8 GHz with Hyper-Threading technology. It has a 400/533/800 MHz FSB and supports dual channel DDR 400 memory up to 4GB with ECC, two serial ATA devices, and an AGP 8X, two PCI-X, and four PCI slots.
Advantech: 877/294-8989; www.advantech.com/eAutomation Fast PLC Can Be Checked Remotely
The FA-M3 R programmable logic controller has a scan time of 20,000 steps/msec, handles up to 8,192 points, and has up to 310K word program storage. Remote operation maintenance can be accomplished via an Ethernet connection that supports diagnostics and email alarm notification. Software programming is object ladder with blocks and macros that can be coded independently. It supports data exchange with other Windows-based applications.
Yokogawa: 800/258-2552; www.us.yokogawa.com PLC Performs Motion Control
The 317T PLC uses Step 7 software, so that only one program is needed for PLC and motion control on up to 16 axes. Motion control functions include positioning in absolute, relative, additive and superimposed operating modes, geared synchronous motion, electronic cam disc and cam, and moving to a positive stop. It also has a measuring probe for print mark correction.
Siemens Energy & Automation: 770/751-2477; www.sea.siemens.com Web Enabled Controller Answers E-Mail
Enhancements to the Model 5200 Blue Fusion automation controller include a built-in web server that enables users to monitor and control 192 I/O points and up to six axes of motion via the Internet. It sends alerts or production data via email messages, and users can send an email with customized instructions to modify the operation of the controller. The controller supports UDP, TCP/IP, HTTP, Modbus Master/Slave TCP, and DHCP protocols.
Control Technology: 508/497-0335; www.ctc-control.com ASI-I Links PLCs
The SST-ASI PLC Network Interface Modules connect an AS-Interface network to Allen-Bradley ControlLogix, CompactLogix, MicroLogix, and SLC 500 programmable controllers. The modules support up to 124 AS-Interface slaves and include diagnostic capabilities for power, communication, voltage and configuration errors.
Woodhead Industries: 877/427-0850; www.Woodhead.com Tiny Industrial PC
The smallest model in the C63xx series of control cabinet PCs measures 3.7 x 7.7 x 8.9 in. Base units are fan-less with heat fins. The PCs handle PLC tasks yet have the operating and communication options of a modern PC. Units have an Intel Celeron or Pentium III processor, TwinCAT software, DVI and USB interfaces, an on-board Ethernet interface, and optional PCI fieldbus cards.
Beckhoff Automation LLC: 952/890-0000; www.beckhoffautomation.com Big Screen PC is Touchy
The Telemecanique Magelis industrial PC has large-format 12 or 15 in. backlit touch screens, rugged steel frames, and industrial grade components. It runs Microsoft Windows software, employs the company’s Ethernet-enabled Transparent Ready architecture, and incorporates Web and Modbus TCP/IP technologies.
Schneider Electric: 800/392-8781; www.us.telemecanique.com Tiny PLCs Run With Big Boys
The FX1S and FX1N SuperMicro programmable logic controllers are small, but have the power, speed and functions of larger PLCs. Both have two-axis motion control with built-in 100 kHz outputs, 100 kHz inputs, three communication ports and embedded PID. They handle 10 to 128 I/O and can be networked in a variety of methods including Ethernet for remote maintenance and data gathering.
Mitsubishi Electric Automation: 847/478-2100; www.meau.com Flat Screen Panel Computer
The compact A2T-15 industrial panel computer system has a color TFT flat panel display, analog resistive touchscreen, and NEMA 4X stainless steel bezel, making it suitable for factory floor environments. It has Ethernet ports, multiple USB ports, Pentium 4 architecture and two PCI expansion slots. Price is $2,495.
Ann Arbor Technologies: www.a2t.com Fast Control Platform
CompactRIO embedded control and acquisition platform lets developers define multiloop analog PID control systems with loop rates exceeding100 kS/sec, digital control systems with loop rates up to 1 MS/sec, and PLC controls that evaluate multiple rungs of Boolean logic in less than 25 nsec. It has a real-time embedded processor, four or eight-slot reconfigurable chassis containing a user-programmable FPGA, and 10 hot-swappable industrial I/O modules.
National Instruments: 800/258-7022; www.ni.com Tiny Microcomputer Keeps Quiet
The Model LPC-401FL fanless, noise-free computer measures 10 x 5.82 x 2.79 in., making it suitable for deployment in space-challenged applications. It has an Intel Pentium 4 1.33 GHz Celeron processor, 2.5 in. high-shock hard drive with up to 80GB storage, and LAN, serial, parallel, USB 2.0, FireWire, VGA, PS/2 mouse and keyboard ports. It is compatible with WIN 9X/NT/2000/XP and Linux operating systems. Prices start at $795.00.
Stealth Computer: www.stealthcomputer.com Fieldbus Controller Goes Ethernet
Enhancements to the PFC Ethernet TCP/IP Programmable Fieldbus Controller include increased data memory of 256KB, a multi-tasking operating system, the ability to make on-line programming changes, and a real-time clock for time stamping and scheduling applications. Programs are stored in flash memory for recovery from power failure, eliminating the need for periodic battery replacement. It supports ModbusTCP and EtherNet/IP and interfaces to Microsoft .NET, UNIX, and LINUX-based systems.
Wago: 262/255.6333 ext. 135; www.wago.com CE-based Control Panel
The CP3xxT-Studio-IB control panel combines the functions of a PLC and an operator panel. It runs under Windows CE, has 48MB of user program memory and a 10/100Base-T Ethernet port, is programmed with Entivity Studio flow-chart software and a common OPC tag database, and runs Iconics PanelWorX HMI software. The computer is available with 6, 10 and 12 in. TFT displays with touch screens.
Phoenix Contact: 800/586-5525; www.phoenixcon.com Brick-Style PLC Gets Off Its AS-I
Enhancements to the MicroSmart brick-style PLC series includes an AS-Interface master module and an 8 point 120 VAC input module. The AS-I allows the PLC to communicate with slave devices such as sensors, actuators, and remote I/Os, using signals transmitted over the AS-I network. The 120 VAC input module allows a user to apply 120 VAC directly into the PLC input card. This reduces the need for additional signal conditioning devices. Programming is via WindLDR version 4.5 software.
IDEC: www.idec.com Stainless Steel Computers
The 8901 and 8903 stainless steel PCs meet caustic washdown, NEMA 4X, and IP66 ratings. Each has a TFT display, shatterproof polycarbonate screens, IP67 compliant I/O connectors, an operating temperature range of 0-50 °C, a VESA 100mm mounting pattern, and an internal cooling system. Options include shatter-resistant resistive touch screens, a NEMA 4X keyboard, Electro-Polish finish for clean room applications, and an extended temperature range of -40 to 50 °C.
Comark: 800/280-8522, ext. 2; www.compark.com PC Meets DOD Specifications
The W130 notebook computer meets MIL-STD-461E standards for operating in environments with high electromagnetic emissions. It is dirt-proof, dust-proof, waterproof, and withstands three-ft drops. The system has an Intel Pentium processor, wireless network, cell phone access, LCD screen, 40 GB hard drive, up to 1 GB RAM, and is bundled with Windows 2000 or XP operating systems. Prices start at $3,000.
Getac: 949/699-2888; www.getac.com Temperature Acquisition Module
Suitable for use with handheld computers, the OM-MT20 acquires temperature data. It has manual and automatic data logging software that installs on a handheld computer, then transfers data to a PC in comma-separated value file format (.CSV), which will open in most common spreadsheet, word processing, charting, statistical or other analytical software programs. Price is $199.00.
Omega Engineering: 203/359-1660; www.omega.com Counters for PLCs
The H0-CTRIO High-Speed Counter I/O module for DL05 and DL06 micro PLCs accepts high-speed pulse-type input signals for counting or timing applications, and provides high-speed pulse-type output signals for stepper/servo motor control. It has four DC inputs, two DC outputs, one quadrature encoder counter up to 100KHz, two single-channel counters up to 100KHz, and two high-speed discrete inputs for Reset, Inhibit, or Capture. Price: $189.
AutomationDirect: 678/455-1805; www.automationdirect.com