Knowledge Base

How WebVue uses the available bandwidth

• WebVue sends an update request to the server at the period defined by the property Client polling delay The default is 1 second. This message is quite small at about 600 bytes.
• The server replies with a message containing the changes that have taken place on the current mimic since the previous message (color change, value change and so on). This message is also relatively small unless opening a new mimic.
• If the WebVue mimic contains any of the viewers (Alarm Trend and Log) there will be additional data exchanges with the server. The Viewers’ refresh rates are configured by the Trend, Log and Alarm refresh period properties which are also 1 second by default.

Tips to minimize/optimize WebVue’s bandwidth use

• The time taken to load a mimic on WebVue is considerably longer than on PcVue. A factor of 10 is rough guidline. Therefore keep the mimics as simple as possible. Aim to keep the mimic file size less than 100kB even with a high performance connection.
• Where the bandwidth is very limited consider creating a set of mimics specifically for WebVue.
• Minimize the use of animations that update frequently (for example display of the Time variable).
• Change (increase) the refresh periods for the Viewers although you must keep in mind that the responsiveness and real-time feeling will suffer as a result.
• Enable the DataCompression property in the WebVue Settings dialog. Note that although this will reduce the bandwidth required it can reduce the overall performace of WebVue due to the additional processing required to compress and de-compress data.
• In the case of WebVue time-out because of limited bandwidth you can try changing the SocketTimeout property in WEBVUE.DAT. This is set to 10 seconds by default but can be increased if necessary. The maximum suggested value is 30 seconds.
• The WebVue version that appears in version 11.0 and 10.0 SP2 has performance improvements related to the loading time of the first mimic and of the viewers. While these improvements don’t directly affect the bandwidth, the use of these versions (or later) is recommended for the performance improvement perceived by the User.

How WebVue treats images

We have put this information here as large images use considerable bandwidth when loading and so some background information on how WebVue treats images is useful. The WebVue server converts the standard image formats supported by PcVue as follows.

JPG and BMP images without transparency are compressed according to the property CompressPercent. The default setting is 70%. Increasing this further can reduce the image file size but will have a detrimental effect on the quality of the image when displayed in WebVue. This property can only be changed by directly editing webvue.dat found in the WEB folder of the project.