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Why go to Electronic Logs? 20 reasons not to hesitate! Shift Handover Management: Taking care of the most critical period of the day. Multiple Logbook Applications: Making the most of Best of Breed Logbooks

Push and Pull Historians

Push and Pull Historians: Very different horses for very different courses. Of course, we could classify process historians a hundred different ways, but if we had to just stick to just two classes, then, from an architectural viewpoint, we could separate historians into either Push Historians or Pull Historians. Both kinds of historian put information into a database of sorts, but the deeper we look, the more we see how fundamentally different they are. Push historians typically reside within the SCADA package and push the data out into a file for analysis. They can be triggered to store very fast information, typically into a flat file when a specific event occurs. Often you would know exactly what you are looking for and you would identify the specific tags that you are interested in. In summary, push historians store information at fast rates, but for few tags, for a small period of time and often there are only a handful of people are interested in this information. Pull historians on the other hand are diametrically opposite in nature. They reside outside of the SCADA system and pull the information from multiple SCADA systems and are generally concerned with a lot of information. We just pull all the information in and let the database machinery take care of it. We hear our customers say..."We don't know what we want so please store ALL the information of all 100 000 tags for at least 5 years! AND we want the following 50 people to have access to this information AND it must be shown in an easy to use graphic format. Oh AND please can you put it into our existing standard database so that we don't have to buy one of those wretched proprietary ones!" Surprisingly, pull historians like jHistorian are quite up to this task! Which one do you choose for your system? Well often, you will need both. For low down intense debugging of troublesome tags, use the push historian. (Most SCADA systems do have a mechanism for this.) For everything else, (and everybody else,) use a pull historian like jHistorian and a web based browser package like jBrowser. View the on-line Demo Please send me more information Click here to view our Price List.