Electricity + Control May 2019

round up CONTROL SYSTEMS + AUTOMATION

Selecting the smart PLC vendor and system. In cases where space is at a premium, PLC and HMI all-in-one control- lers have an advantage. Some PLC manu- facturers provide PLC and HMI controllers with on-board or snap-on I/O modules, which save space and reduce wiring. Data communication and more Flexibility is key – the more protocols the selected brand of PLC supports, the great- er its scope of interoperability with existing applications and third-party devices. Impor- tant industrial data communications proto- cols include Modbus, Ethernet IP, CANopen and various CAN bus dimensions such as CAN layer 2, and others. The PLC manufac- turer should also provide software utilities that enable you to implement proprietary third-party data-com protocols such as se- rial RS232/485, or TCP/IP. The visibility of operating data and diagnostic information is another important consideration, as is re- mote access via the web server with sup- port for SMS messaging or email. Intelligent software Intelligently designed software can help save time. In this regard, there are two particularly important factors to consider: ease of use – such that the programmer does not need to search for elements when programming and can understand the programming steps intuitively; and re-usability – which should apply for all pro- gramming functions – the ability to re-use your work across projects will save a lot of time.

There are a number of manufacturers of programmable logic controllers (PLCs) for automation control projects. However, most of us have a preferred brand, a plat- form that we return to time and again. This is because familiar = fast. You know the hardware range. You know the software. You know what to expect and you have a sales representative on speed dial. For these reasons, selecting the manufacturer that stands behind a brand of controllers is important – just as important as deciding on your central processing unit (CPU) and input/output (I/O) requirements. ACDC Dynamics suggests the following factors should be considered in selecting a smart PLC vendor. A range of PLCs The selected brand should have a com- plete product range that can meet the requirements of your customers. PLCs must be able to supply sufficient memo- ry to support I/O, log and manipulate his- torical data, as well as execute the con- trol program. Where execution speed is critical, the CPU processing speed must be considered as well. Other considera- tions should take account of the sector’s standards, whether or not the application needs to comply with hazardous environ- ment standards, CFR-21.11, or the spray- and-wipe standards of the food and bev- erage industry. Influenced by the mobile industry, customers are likely to expect HMI colour touch-panels to provide the communication window between operator

Service and support It is important to look for PLC manufactur- ers that offer a high level of customer care in both technical and sales support. Per- sonal support – from people, as opposed to automated systems – on a 24/7 basis, is also valuable. It can make the difference to meeting deadlines and retaining custom- ers. Support documents, specifications and guides should be readily available too. And ideally, this support and documenta- tion should be available at no extra charge. Total cost of ownership Cost is never limited to the purchase price of the PLC. Development costs and future maintenance can make or break your profit margin. When buying a PLC, it’s important to 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: ACDC Dynamics, email: info@acdc.co.za

In selecting the right PLC for automation projects it’s important to consider the support services too.

Easy planning of I/O stations

The result is shown directly in the main window of the software. Once users have finished configuring the I/O station, they have an I/O station that is technically correct along with the corresponding bill of materials (including detailed product descriptions). To mark the I/O station or configure a complete terminal strip, the configured result can be exported from Project+ and completed

Version 3 of the Project+ planning software from Phoenix Contact is available to download. I/O stations from the Axioline F and Inline product families can be configured using the software, without re- quiring extensive system knowledge. The software offers users a choice of possible connection sce- narios based on the automation-related signal types they have se- lected and those that correspond to the I/O devices they intend to connect. Based on this selection, Project+ determines the device combination for all required connection scenarios. The software optimises the selection according to various as- pects such as price, station width and the number of devices. Us- ers do not need to be familiar with specific configuration rules. Every time the user enters or changes the signal types, the software selects the appropriate I/O product for the I/O station.

in the PROJECT complete planning and marking software from Phoenix Contact. Enquiries: Phoenix Contact. Tel. +27 (0)11 801 8200, or email info@phoenixcontact.co.za

Project+ Version 3 planning software is now available.

16 Electricity + Control

MAY 2019