1756-EWEB Module: Web Server and More - Rockwell Automation

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105. Click the See message you are going to send button again and make sure that a smaller message is displayed in the popup. 106. Click OK. 107. Click the Send to Instructor button. 108. Click OK on the dialog that confirms the message has been sent. Your message should arrive in your instructor’s inbox momentarily. Why the EWEB does not replace the PanelView Plus • The EWEB is a single threaded Web server, it cannot do high speed data collection. This is intentional, so that control system performance is not compromised by the presence of the EWEB. • All the tag names have to be known in order to read or write them. All the benefits of FactoryTalk Directory Direct Tag Referencing are lost. • There is no simple HMI graphics editor that allows you to drag and drop objects onto screens. Any graphic HMI pages would have to be written as web pages. • Web pages need to be refreshed. This effect is virtually non-existent with HMIs. • There is no Alarming or Unsolicited data from the EWEB. • Data Views can access only Controller Scoped Tags, and only tags of type BOOL, SINT, INT, DINT, REAL or STRING. Custom Web pages do not have these limits. • Only 2500 tags can appear in all Data Views combined, but there is no limit to the number of Data Views or the number of tags per Data View, except for the 2500 total tag limit. Custom Web pages do not have these limits. • Quick and Dirty Simple Summary: HMI: Allows you to look at lots of data locally. EWEB: Allows you to look at a limited amount of data from anywhere. LAB 1: 1756-EWEB Module Page 22
EWEB Performance, EWEB Effect on System Performance The following table has been taken from the EWEB User Manual. Extra Task: When a Data View is edited or created from within the EWEB’s default home page, the only tags that can be accessed are of type BOOL, SINT, INT, DINT, REAL and STRING residing in controllers in the local chassis. There is also a limit of 2500 tags in all Data Views. However, when Web pages are created, these limitations do not exist. Your mission is to create a project in your FlexLogix controller and have your EWEB retrieve data from that FlexLogix controller. Modify the get.asp file by changing the path of ReadLogixTag. LAB 1: 1756-EWEB Module Page 23
Page 1 and 2: Hands-On Lab Workbook 1756-EWEB Mod
Page 3 and 4: Background: The EWEB module allows
Page 5 and 6: LAB 1: 1756-EWEB Module Only the at
Page 7 and 8: Different Data Views can act as dif
Page 9 and 10: 34. You must now create three tags:
Page 11 and 12: 44. In the browser’s address bar,
Page 13 and 14: 56. We want to prevent a third part
Page 15 and 16: additional software to view (unlike
Page 17 and 18: 80. Close ALL instances of Internet
Page 19 and 20: ased, it is platform independent. B
Page 21: In this example, we will send data

1756-EWEB Module: Web Server and More - Rockwell Automation

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