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KEPServerEX by Kepware TechnologiesProduct Review
Overall Rating:
By Naeem Ismat
OverviewAs you are probably aware, over the past few years there has been an increasing trend in industrial controls and automation to move the communication from proprietary drivers to standards based OPC server technology. There are various reasons for this, but the most important factors are data interoperability between the control systems and the enterprise not to mention the decreased infrastructure costs that come from being able to standardize on the infrastructure elements. KEPServerEX is a 32 bit server application from Kepware, and is the most widely OEMed product in the automation industry. You can use this server instead of traditional old-style proprietary drivers for bringing data and information from a wide range of industrial devices and systems into client applications on your Windows PC. KEPServerX is built using the latest OPC standards from the OPC Foundation and is a very good choice for anyone looking to expose their plant and manufacturing data to other PC applications. The KEPServerEX is also a great choice for those who are using existing OPC drivers but find they are limited in what they can do with them, for example, sharing data with 3rd party applications.
KEPServerEX falls under the category of a "server" application. The most common use of this OPC server is on the plant floor for connecting HMI/SCADA applications to industrial devices which may be either Allen Bradley’s ControlLogix/PLC5/SLC, GE’s PAC systems or any other manufacturer’s device. In the past, it was very common to use customized applications for relaying data and information up and down the enterprise system within the SCADA infrastructure. In today’s industrial market, OPC servers have come to mean the sharing of manufacturing or production data between a variety of applications ranging from human machine interface software and data historians, to large MES and ERP applications. This piece of software, being very cost effective, has made it very easy for end users to grab data from plant floor/field devices and provide it not only to SCADA but also to feed any OPC client software, which may be your Historian, ERP, web portal, reporting software, and other. End users can now use historian/data loggers without using SCADA systems, which was not at all easy to do in the past. By using these OPC servers you can easily feed data to any proprietary historian or relational database.
Software DemonstrationA two hour demo of KEPServerEX OPC Server (Super Server Pack) is available for downloading and testing from Kepware’s website. Registration is required before downloading but the process is quick and simple. The download of KEPServerEX includes all currently available OPC drivers, the fully featured OPC Quick Client, comprehensive Visual Basic examples, and more – all in a single download. The download is unicode only. You need to contact Kepware for the ANSI version if needed. The demo drivers are only limited by time – they do not have tag count limits so you can test a fully functional product with all the features. To download a demo visit this link: http://www.kepware.com/Products/products_download.asp
Installation ProcessThis software offers a very easy and smart installation user interface. During installation the user is given the option to select drivers for communication. Almost all major and popular controllers and protocols, plug-ins (OPC DX and Datalogger), OPC Client and documentation (source code examples and some OPC specifications) are available. On selecting any driver, KEPServerEX shows that either your specific processor and communication protocol are supported or they are not. It took approx 40 seconds, both on Windows 2000 and Windows XP operating systems with some selected drivers, and 50 seconds on Windows Vista with all drivers (complete install) on our test computers. Actually, installation was just clicking through a few buttons and was smooth with no surprises and no system restart required.
GUI (Graphical User Interface)
This server provides a uniform interface to all of its available communication drivers. A simple and easy to understand interface shows configured channels, devices, tags, and events at a glance. This area also allows channels, devices, and groups to be added to a project. You can add many devices utilizing multiple drivers, all within the KEPServerEX interface, without worrying about learning new communication protocols or spending time understanding new applications.
Setup and maintenance
By right clicking in this area, a context menu will be displayed that allows these elements to be added or modified. I found that anyone with basic knowledge of field devices can configure this OPC server easily. With knowledge of field device parameters and other communication parameters, communication can be established very quickly. The KEPServerEX interface provides separate wizards for adding a channel and devices. These wizards walk you through all the configuration steps.
I liked KEPServerEX’s ability to set up multiple channels with a variety of devices and protocols. Many leading industrial software vendors are still lacking in this useful feature and their customers have to install multiple drivers when they have different protocols or devices. So communication with three types of PLCs could end up requiring installation and configuration of three different OPC servers in HMI/SCADAs. With KEPServerEX, you have one simple interface for different devices from different vendors. While testing, I configured one configuration file to test communication. It worked as expected at the first attempt and I was able to see “good quality” data immediately. The KEPServerEX OPC server offers all commonly required configuration tools, which is something that systems integrators or end users would love to see. You can export a configuration file and alias maps file to CSV, make mass level changes, and import them back. I noticed many other good features which are configurable by the user, including backup of the last good project file (configuration file) prior to overwriting the file with new changes, many view options, server options to run in the foreground or background (as a service), options to log events that occur in the server, and more. If someone wants to use XML File Configurable, KEPServerEX will certainly read an XML file for configuration.
Runtime ConfigurableSystems integrators/end users mostly want to change com ports on the fly. KEPServerEX enables you to change core configurations at runtime. Overall, almost all features are runtime configurable with this Kepware server.
Ethernet EncapsulationKepware has added this technology to make your job easier, and Ethernet encapsulation is built into all serial drivers (for Remote Serial over Ethernet). Traditionally, additional software was installed to make a terminal server appear like a serial port on your operating system. Although this software can make using a terminal server very easy, there is one exception - timing. From my technical support experience, I know software that often accompanies terminal server devices has not been optimized to work with the requirements of the plant floor environment, and it usually causes frequent communication errors, continuous breaks in communication, and long and annoying delays waiting for the supplied software to reconnect to the terminal server. At some sites, these types of problems are issues. So it is believed by industrial gurus that the software supplied with the terminal server would not yield the most optimal result in terms of performance or reliability. Kepware has adopted a better approach to this issue and has incorporated the functions needed to connect directly to a serial device connected to an Ethernet based terminal server. Ethernet Encapsulation has enhanced the ability of KEPServerEX serial drivers to communicate directly with terminal servers.
OPC Compliancy OptionsKEPServerEX offers the choice of using OPC Data Access Specifications versions 1.0, 2.0 and 3.0 either selectively or all of them simultaneously, as there may be times when forcing the server to use one version over another may be necessary. In addition, the server provides the highest level of compatibility with the OPC Foundation's specifications. In testing, however, it has been found that being fully compatible with the specifications and working with all OPC client applications available in the field is a different matter. The OPC Compliancy option in KEPServerEX enables you to tailor the operation of the server to better meet the needs of unusual OPC clients. Most of the time these options will not need to be adjusted for the OPC client applications you use but in the event you do need the option, you have it.
Compatibility with Legacy ApplicationsSometimes end users only want to upgrade their OPC server, but compatibility with legacy client applications have some limitations such as the size of tag address paths, etc. KEPServerEX takes care of this issue and also has a nice Alias Map feature which provides both a mechanism for backwards compatibility with legacy server applications and a way to assign simple alias names to complex tag references. This OPC server automatically created the alias map for me. I was also able to add my own alias map entries to complement those created by the server and even filtered out the server created aliases so that I could only see my own. So, after mapping, instead of using the complete path (Channel1_Crusher.Device1_PLC5.Group1), I used just a short alias (Area1_PLC5).
Supports Native Interfaces for GE Fanuc and Wonderware’s SCADAsSupport for GE Fanuc and Wonderware’s SCADA application may not be attractive to all users but I can’t ignore it due to the very large user base of both GE Fanuc and Wonderware SCADA software. During my testing with GE’s SCADA iFix (which has more than 350,000 installations), I was able to configure it in iFix’s SCU file as a driver. What that means is I don’t need to use an additional OPC client driver between iFix and the KEPServerEX OPC server to establish communication. I am certain every iFix user would appreciate this feature. By creating a tag in the iFix database with KEPServerEX as a source in an I/O address, I saw field values in seconds. I noticed that if I install multiple drivers from KEPServerEX to communicate with controllers from different vendors, I just need to add the IDS driver once in an iFix configuration. Similarly, when it comes to tag creation, you are given two choices, static tags or dynamics tags. In my testing both worked as expected. Both approaches have some pro and cons. In static addressing you can create tags which reside in the IDS configurator. These tags have an address field which references the address or tag in the controller. When using static tags, auto create can be performed to bring in all tags in the controller when using the ControlLogix Ethernet driver. It gives the user the ability to control the data type and scan rate directly from the IDS configurator. You can use static tag scaling in the server. But if you make a change in a tag, you will need to change the address both in the IDS configurator and the SCADA database (iFix in this case). By using the dynamic addressing method, the user can specify the address or tag directly from the iFIX database. All that is needed in the Kepware server is to create channels and devices. In this type of addressing, one of the benefits is that when you make tag changes, you only have to make them in one place (iFIX database). You may also control the data type and scan rate of your tags, if you need to append the I/O Address in the iFIX database. But, when using this method, you can’t use the auto create feature.
DiagnosticsAs nothing in the world is perfect, problems may arise with communication, networks, field devices, installations, and more. I pay special attention to the diagnostics tools offered by any industrial software vendor. A good diagnostics tool saves a lot of time during investigation of any issue and when narrowing down a problem. KEPServerEX offers various diagnostic views in helping to determine what the problem may be. Two diagnostic tools available in the server are the OPC Diagnostics and Channel Diagnostics windows. These views provide both server and driver level diagnostics for advanced users. Additionally, many system tags offer consistent diagnostics across all drivers.
KEPServerEX also offers statistics tags which are very useful in providing feedback to client applications regarding the operation of the channel communications in the server. This feeback is useful when troubleshooting and when monitoring large scale applications.
RedundancyDuring testing I found that KEPServerEX does not have any built-in redundancy and there is no automated detection of CPU failure in this version of KEPServerEX server. Further searching of the Kepware product line revealed RedundancyMaster, OPC redundancy software, as a solution. There are two ways of handling redundancy and it depends on the type of end user. First, if someone really needs redundancy, my first choice and recommendation would be RedundancyMaster as a solid solution. As a second choice, I may use the system tags of KEPServerEX at either the channel or device level. In addition to channel-level and device-level system tags, there are also application-level system tags which enable client applications to monitor the status of the server. As a workaround, these can be used to get information about the system and error conditions. The OPC server will enable you to manually make changes, on the fly, to your KEPServerEX configuration. For implementing a redundancy solution with automatic failover, the KEPServerEX driver does not support configurable redundant channels or devices in the driver configuration. Although you can set up multiple channels/devices with the same network address information, there is no functionality to switch to or make one of the channels "primary" when a failure is detected. As a workaround there are manual options that you can utilize. This driver has special parameter control tags which are a powerful feature and can be used to modify the operational characteristics of the server application. Using the parameter control tags you can implement redundancy by switching communication links or changing the device ID of a target device, all on the fly, For example, System_NetworkAdapter can be used for switching the card being used for communication through the PC. In my testing I tried a parameter tag _NetworkAdapter. This tag enabled the current NIC adapter in use by the driver to be changed on the fly. As a string tag, the name of the newly desired NIC adapter was written to this tag in string format. The written string must match the exact description of the desired NIC in order for the change to take effect. NIC names can be obtained from the _AvailableNetworkAdapters tag. It worked great and, on changing the NIC selection, the driver was forced to break all current device connections and reconnect, which makes sense and was exactly what I expected. In another test I played with the _Error and _DeviceId tags. In the SCADA software I used a text block/tag for ._System._DeviceId and a digital block/tag for reading ._System._Error. A schedule based on events which was checking the _Error tag was set up. If the tag’s value equalled 1 then the logic in the event was written to change the IP Address on the _Device_ID tag. It worked as expected. If users want to reinvent the wheel and set up redundancy by using existing features, the option is there or you can get a ready-made solution using RedundancyMaster. Bear in mind that the user will have to determine when it is appropriate to modify any system tags that trigger switches to other computers running KEPServerEX. The user will also have to determine how these changes will be executed and how the writes to these fields will be set up in the HMI software. The bottom line is if you have experience handling lots of tags and know how to configure on the fly, configuring system tags is the answer; otherwise go for RedundancyMaster, a readymade separate redundancy solution from Kepware.
Documentation and SupportThere is very well written and comprehensive documentation for KEPServerEX. The documentation includes a main server eBook and then each driver has its own help file which provides information on devices supported, communication parameters, cabling, addressing, and error messages. In addition to ebooks, connectivity guides with training examples for commonly used HMIs/Clients are available in pdf format on Kepware’s website. Free troubleshooting guides are also available on the Kepware website under their support section. Kepware provides unlimited e-mail support demo or registered licensed versions for KEPServerEX. They provide a total of two hours free phone support for all registered software after payment of the applicable license fees. Unlimited phone support maintenance agreement is also available. All updates and patches are made available through Kepware's website.
Fully BrandableKepserver is trusted by many vendors as companies OEM the KEPServerEX server. For vendors looking for a standards based interface between the devices they manufacturer and client applications, Kepware offers a good option.
Conclusion KEPServerEX is an OPC server using the latest generation of OPC server technology. The OPC server has over 100 drivers that support thousands of model types running on plant floors all over the world, with a single and consistent interface enabling you to truly experience the promise of OPC.
Kepware designed this product intelligently and have kept the hardware protocol driver separate from the server technology. The benefit of this separation is that it enables a user to use one or more drivers in the server at the same time. This driver offers a lot of application level, device level and systems level (Ethernet and Serial) tags which can be used to set up very powerful and robust communication between controllers and SCADA software for almost any type of industry. Access to these tags is done through special supervisory screens that enable a plant engineer to make changes to the communication parameters of the server on the fly if needed. I have not detected any missing features from an OPC server point of view, in comparison with what others are offering. Rather, at a very reasonable and competitive price, KEPServerEX maximizes the promise of OPC with a single OPC server interface for multiple protocols. I truly liked this OPC product as it offers a unique architecture and all drivers provide data seamlessly to client applications through a consistent server interface as well as user-configurable protocols, by using technology that scales to your needs. After finding all these strengths, I can say that KEPServerEX is a reliable and powerful OPC server without overheads, through built-in Ethernet encapsulation, error recovery, timing adjustments, write optimizations and the ability to run as a service.
For the purposes of this review, the following product versions were used:
Vendor Recommended Specifications for KEPServerEX:
Intel Pentium III 400 MHz or equivalent processor Required Processor Speed: Sufficient to run operating system Required Disk Space: 40 MB of available disk space Required Memory (RAM): 512 MB installed (256 MB free) Other: Available Serial Port or Ethernet card
Software Specifications: The following computer hardware was used for the review of OPC Systems.NET:
OS: Window Vista Ultimate Processor: AMD Athlone 2.11 GH RAM: 3GB
Computer 2: This review is published by the OPC Training Institute. Copyright ©2008 OPC Training Institute (OPCTI). All rights reserved. The information contained in this review is proprietary to OPCTI. No part of this review may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from OPCTI. |
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KEPServerEX is OPC Compliant Certified, has been tested by an independent certification test lab, and has passed all the tests required for the specifications it supports. This means that KEPServerEX has passed independent certification testing that includes interoperability testing, compliance testing, performance testing, stress testing, white box testing, behavior testing and environmental and usability testing.
