I/O Modules: Product research and advice from <em>Control Engineering</em> subscribers
Control Engineering readers offered advice about I/O modules trends, use and capabilities in an online survey emailed on Jan. 7 to subscribers of the Control Engineering System Integration, Machine Control, and Process and Advanced Control eNewsletters.
By Jan. 11, 506 survey respondents represented a “next project” I/O count of more than 389,850 I/O points, an average of more than 770 I/O points each.
Most-needed I/O module features are digital and analog capabilities, and a design that plugs into a base or rack, snaps on more points, and can mix digital and analog. Also popular are capabilities for use within an enclosure, diagnostics, optical isolation, and easy expansion. Finding the right mixture of discrete, analog, and high speed I/O for specific applications, within budget, is a key challenge, agreed Jeff Payne, PLC, I/O and PC control product manager for AutomationDirect. Payne said vendors offer high I/O density of 32 and 64 points. Tighter designs save users’ money, Payne says.
In one example, Ingersoll CM Systems Inc.’s next generation deep fillet rolling machine saved 60% in costs compared to previous I/O modules, said Gary Munger, Ingersoll controls engineering manager. Savings came with fewer machine components and use of more economical Balluff IO-Link hubs. Fewer components also reduced the possibility of failures, Munger said.
Programmable logic controllers account for most I/O connections, survey respondents said, more than three times the next largest connection, a distributed control system (DCS) or process automation system (PAS). Vendors have responded with wide-ranging connection capabilities. Omega Engineering’s Universal Remote I/O Modules connect to any PLC, the company says, offering up to 31 I/O modules daisy-chained per RS-485 link. They’re DIN-rail mountable, have optical isolation, and, at 0.69-in. x 3.94-in. x 4.72-in. (17.5 x 100 x 120 mm), can fit in small panels.
Survey respondents said industrial Ethernet and Ethernet connections account for more than half of network protocols used, followed by fieldbus, device-level, sensor-level, and wireless networks. Wireless designs are also said to resolve other issues.
Simatic ET 200pro IWLAN from Siemens Industry Inc. saves significant communication cabling and installation costs with wireless connectivity from any distributed I/O station and modules. The rugged IP67-rated design can be machine-mounted, without an electrical enclosure, Siemens says.
Nearly one-third (30%) of respondents said they use I/O modules with embedded intelligence to replace another controller. New I/O offerings for Eaton Logic Controllers (ELC) have smart I/O adapter modules that enable distributed I/O with limited local logic control. ELC distributed I/O communicate via EtherNet/IP and Modbus TCP Ethernet protocols, Modbus RS-485, and DeviceNet.
Write-in advice: Plan ahead…
Respondent write-in advice covered vendors, price, quality, lifecycle, networks, power and grounding, testing, and more. Respondents said to involve the owner early during the selection process; keep it simple; and leave room for spare I/O and slots. Develop standards for wiring and tagging wires, another said, and look at conversion rates to ensure they match control requirements. Look for distributed capabilities to place the I/O close to point of use and minimize installation and commissioning time.
What networks do you need your I/O systems to support?
Check all that apply. Base: 505 replied.
% / Protocol type / No. responses
62% Industrial Ethernet protocol 316
Update: Due to a spreadsheet oversight, the print edition listed wireless response at 57, about 11%. Actual was 119 respondents, about 24%.
Source: Control Engineering research
Study usage, location, customer requirements and future expansion plans. When sizing, determine how the finished control project should look in a drawing, identify physical points, separate by point type and signal used, compare with available points, and add necessary control hardware to connect the rest of the points.
Regarding networking and diagnostics, the biggest issue, said one respondent, is “the addressing between the I/O and the attached device. It seems that almost every vendor has its own addressing scheme. Use care and look into compatibility and ease of communication between devices.”
Remote I/O has come a long way for simplicity of configuration, update speed (now in real time), and cost effectiveness. Do research and take advantage of the new protocols, especially Ethernet-based ones, another said. Pressing I/O module-related issues are tied to protocol compatibility, ability of a node to multiple I/O types, and I/O module sizes, agreed Charlie Norz, product manager, Wago-I/O-System. Some products communicate in more than 16 protocols, Norz said, and save space inside machines.
On lifecycle issues, respondents said to leave room for expansion later and check how long current models will be in production and have support. Also ensure application engineering support and documentation are in the local language. A broad choice of I/Os is preferred. International standard programming, IEC-61131-3, is “very preferred.” ABB says its AC500-eCo I/O modules are easy to maintain, have a wide range of expansion modules, and the related controller uses IEC 61131-3.
Regarding power and grounding, noise problems can be avoided by using linear power supplies in lieu of switching power supplies. I/O should be hot swappable, not require downloads after connection, have channel-to-channel isolation, be G3 compatible, and have less power dissipation. “Along with isolation to remove ground loops,” said Bill McGovern, national sales manager, Dataforth Corp., input protection guards against over-voltages, while noise filtering serves to remove unwanted frequencies from I/O signals.
More on I/O modules from Control Engineering :
– Balluff-I-O hubs save machine builder 60%: Balluff IO-Link ;
– Banner-Wireless Banner Engineering working with Nivis to offer ISA100, WirelessHART ;
– Beckhoff-IO terminal EtherCAT interface for RTD temperature sensors ;
– Emerson – Updated control system rethinks field device connectivity and human interface ;
– GE Intelligent Platforms TranSphere TS Wireless I-O ;
– Invensys-Intrinsically safe I-O subsystem simplifies hazardous area ;
– Machine builder wins control panel design contest 60% less space, 30% less wiring ;
– Pilz – BMW uses Pilz decentralized I-O system, PSSuniversal ;
– Turck – RFID slice Turck BL67 modular distributed I-O system has a Simple RFID (RFID-S) ;
– Weidmuller-Wireless connectivity line ; and
– Yokogawa-Controllers DAQstation anniversary charts evolution of chart recorder – external I/O modules .
– ABB AC500-eCo I/O modules can grow with the application , are easy to maintain, and offer a wide range of expansion modules, basic to advanced.
– I/O modules: Find the right mix, says AutomationDirect – I/O buyers are challenged to find the right mix of discrete, analog, and high speed I/O modules and remain within budget, company says.
– Dataforth DSCA DIN-rail mount isolated analog signal conditioners : Morethan 370 models of Dataforth DSCA isolated analog DIN rail mount signalconditioning modules are said to provide Dataforth Instrument Classperformance, outstanding accuracy, 3-way isolation, and pluggable screwterminal disconnects to simplify wiring and maintenance.
– Eaton Logic Controller input/output adapter – Eaton announces new I/O and I/O adapter offerings for Eaton Logic Controllers (ELC).
– Honeywell Series C I/O leverages the success and experience gained with port-mapped I/O to produce a unique design, the company says.
– National Instruments: 3 distributed I/O hardware platforms – Deterministic Ethernet Expansion Chassis, Ethernet/Serial Expansion Chassis, and Wireless and Ethernet Data Acquisition.
– Omega Engineering Universal Remote I/O Modules – HE359 Series provideS remote I/O for programmable logic controllers (PLCs); the application is no longer dependent on controller choice.
– I/O modules should be high density, easy to wire and configure, and reliable: Opto 22 – Opto 22 says density, ease of wiring, reliability, and auto-recognition setup software are must-have I/O module features.
– Phoenix Contact calls Axioline‘world’s fastest I/O system’ – Slow I/O? Blending Ethernet technology with terminal blocks, Phoenix Contact created the fastest available I/O speed, the company said at the Axioline I/O system introduction.
– Applications, lifecycle are I/O concerns, Rockwell Automation says – Resolving application-related issues and total cost of ownership are among customers’ I/O-related issues, says Rockwell Automation.
– Keeping a low profile and being dense is OK, if you’re an I/O module – Schneider Electric says I/O modules need to take up little space in the cabinet and offer a wide variety of voltage and current values to fit application needs. Distributed I/O on a machine can reduce wiring costs.
– Protocol compatibility, multiple I/O types : Wago – I/O module compatibility, ability of a node to accommodate multiple I/O types, and I/O module size, are important I/O topics, says Wago.
Control Engineering Research Report: 2010 February I/O Modules offers more graphics and survey information not published in this article.