Sparks Electrical News May 2019

CONTRACTORS’ CORNER

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SELECTING THE SMART PLC VENDOR S peed is crucial for success in a field with demanding require- ments and fierce competition. As a professional, you can work with a variety of devices from a number of PLC manufacturers, however, most of us have a preferred brand, a platform we return to time and again. This is because Familiar = Fast. We know the hardware range. We know the software. We know what to expect – and we have a sales rep on speed dial. For these reasons, selecting the manufacturer that stands behind a brand of controllers is a major decision. Here are five factors to consider when making that selection: Broad range of PLCs Your selected brand must have a full product range that can meet the requirements of your customers. PLCs, for example, must be able to supply sufficient memory to support I/O; log and manipulate histori- cal data; and execute the control program. Where execution speed is

Look for intelligent software Saving time is the primary benefit of intelligently designed software. There are two important factors: Ergonomic design means you do not need to search for elements when programming. And logical, consist- ent construction saves time, since the programmer intuitively knows what to do even when programming a particular task for the first time. Service and support Look for PLC manufacturers that offer a high level of customer care. Make certain that support, whether technical or sales, is easily available and prompt. Personal support – meaning from people, not automated systems, that is available 24/7 is extremely valuable. This is what can make the difference in meeting your deadlines and retaining your own customers. Support documents, specs, and guides, should be readily available. ‘The best things in life are free’ – select a company that pro- vides support and documentation at no additional charge.

critical, the CPU processing speed must be considered as well. What are your sector’s standards? Do your applications need to comply with hazardous environment standards, CFR-21.11, or the spray-and-wipe standards of the food and beverage industry? Influenced by the mobile industry, your customers expect HMI colour touch-panels to provide the communication window between operator and system. Data communication and more Flexibility is key – the more protocols your selected brand of PLC supports, the better you can support interoperability with existing ap- plications. Important industrial datacom protocols include MODBUS, CANopen and other flavours of CANbus such as CAN Layer2 and EtherNetIP. Some brands also support protocols such as SNMP and FTP. Check to see if your PLC provides software utilities that enable you to implement proprietary third-party datacom protocols.

Total cost of ownership Cost is not limited to the actual cash you pay to purchase the PLC. Your development costs and future maintenance costs can make or break your profit margin. Therefore, when you purchase a PLC, remember that you are also selecting the company that stands behind that PLC – and that this decision, over the long run, can have a major impact on your success in industrial automation projects.

Enquiries: info@acdc.co.za

SAFETY TIPS FOR ELECTRICIANS

A work site is a dangerous place: this can- not be overstated. With high voltage and large equipment, an electrical contractor is constantly faced with life-threatening dangers and working in these situations calls for perfect electrical safety practices. There are many rules and regulations in place to keep you safe, but common sense, which is often not that common, goes a long way. Many potential hazards are easily spotted and corrected before a serious accident happens. Understand and follow electrical safety tips at all times and all should go well. Safety is your responsibility Always wear the proper safety clothing and protec- tive gear, such as shatter-proof eye protection and non-conductive work boots or other industrial safety footwear. When working with live circuits, use just one hand and keep yourself insulated at all times. Housekeeping is a very important daily task for an industrial electrician. Leaving material or tools on a job site can cause tripping hazards for others. Make sure you clean up your areas as you work. Keeping everyone safe when dealing with current is an electrician’s job; if you spot a defective extension cord, do not use it: repair or replace it immediately. Plan for safety Plan your job carefully and consider all potential hazards before you start. Always be aware of your surroundings, smart ideas include isolating equip- ment from energy sources, identifying potential electric shock and arc flash points, and establish- ing clear approach limits to make sure unqualified workers don’t wander too close. Before touching an outlet or conductor, test it for voltage. Never work on electrical equipment or conductors until they have been de-energised, properly locked or tagged out, and all chance of exposure has been eliminated. Ladder safety Ladder safety is an important component of an elec- trician’s personal safety. Whenever a ladder or other elevated equipment is being used, by you or some- one else, check and double-check for overhead pow- er sources and obstructions. If the equipment knocks down one of these lines, anyone standing close by can be seriously hurt, maybe even killed. Make sure to inspect the ladder or hoist equipment for damages prior to use. In most cases,

SPARKS ELECTRICAL NEWS

MAY 2019