Visualization block

After you select the New Block command, the mouse pointer will look like "+" (a cross) that you can use to mark the borders of the new block. To do it, you should hold down the left mouse button and drag the rectangle to make it the necessary size. You can move the block over the tab using either the mouse or the arrow keys on the keyboard. You can use the keyboard to move the block as accurately as possible.

After you finish marking the borders of the visualization block, you will see the Visualization Block Parameters dialog box (fig.1). First, you should select the OPC tag the indicator will be displayed for. Depending on the tag data type, the list of available indicator types will be formed.

To select a tag, you should switch to the "OPC tag" tab and click the "Select a tag from the server" button. After that you will see the OPC Tag Selection dialog box (fig.2).

Computer - you can specify the name or the IP address of the remote computer. If you need to connect to the server on the local computer, specify LOCALHOST as the computer name. After you enter the computer name, click the "Update" button to get the list of available OPC servers. If the program cannot retrieve the list of servers, the following reasons are possible:

•	OPC Core Components Redistributable from www.opcfoundation.org are not installed on the local and remote computers

Servers - the list contains the list of available OPC servers on the specified computer.

Connect - the button connects the module to the server and tag (if there are any on the server) appear in the "Tags" list after that. It is also possible to connect to the server with a double click on the server selected in the "Servers" list.

Tag selection mode - the list allows you to select one of the modes for selecting tags. Two modes are available:

1.	Automatically retrieve tag names from the server - the program automatically retrieves the list of tags and their parameters from the server. Not all servers support this feature;

2.	Manual mode - you have to specify the names of tags manually in this mode. You should use this method if the server does not allow OPC clients to retrieve the list of available tags.

Filter - it allows you to select only tags meeting the specified condition (by name or by data type) from those available on the server. This feature is convenient when there are a lot of tags on the server.

Tag - you have to specify the tag name, including the full path to it if there is any.

After you select a tag in the manual or automatic mode, click the "OK" button and the information about the selected tag will appear in the Visualization Block Parameters dialog box (fig.1).

After that you should check the connection to the OPC server. To do it, switch to the "Connection" tab (fig.4)

Active - if this option is enabled, the value of the tag will be retrieved from the OPC server.

Update every - the program will retrieve the values from the OPC server at the specified period.

Dead band (%) - the field contains the value of the dead band in percent. If the value of the tag changes within the dead band, the program will consider it unchanged and the value of the tag will not be shown. The default is 0 percent.

After you select the tag, you should configure the display parameters for this tag. Depending on the tag data type, certain indicators will be available. To configure the display parameters, you should select the "Display Parameters" tab (fig.5).

Every visualization block has several elements (fig.6). You can configure every element in the visualization block after you select the corresponding item from the "Element" drop-down list. You can show or hide each of the elements.

You can use the display parameters to specify the exact position of the visualization block and its size. To do it, you should select "Window" from the "Element" list (fig.7).

You can also specify the background color for the selected block and its alignment:

1.	None - the block will be placed according to the user-defined position. The block size does not change;

Left, Right, Top, Bottom - the block will be placed along one of the specified sides. Besides, the block will be resized to fit the tab size. For example, if you select "Left", the block will always placed along the left size of the tab and the height of the block will correspond to the height of the tab;

1.	Title - the program allows you to specify any text as the title of a block and to format it;

2.	Status indicator - it shows the status of the connection to the OPC server. The green indicator shows that the connection to the server is active, while the red one shows that the connection has been broken;

Indicator - the value of the tag can be displayed with the help of various indicators. The program offers more than 20 types of various indicators. Each of them has its own set of display parameters that are displayed as a tree in the fig.5. You can preview changes in this tree of parameters in the preview window to the right from the tree of parameters. Data types the selected indicator can be used for are shown under the preview window;

4.	Frame - the frame allows you to visually limit the block size. When the frame is enabled, you can also resize the block with the help of the mouse;

5.	Current OPC tag value - some indicators are graphical ones it is difficult to tell the precise value of the tag from. This element allows you to display the precise value in addition to the value on the indicator;

6.	Minimum and maximum values for the OPC tag - this parameter allows you to specify one or several conditions (fig.8) that will serve as a limit for the acceptable values of the tag. If the value exceeds the specified limit, the program will show a warning.

•	Specify the type, size and color of the font using the standard dialog box opened with a click on the "Font" button;

You can specify the list of conditions for the "Value", "Minimum" and "Maximum" elements (fig.8). If they are met, the program will display warnings and play the specified sound. To add a warning, select the corresponding element in the list and click the "Plus" button. After that you will see the dialog box where you should specify the necessary parameters (fig.9). Other buttons next to it are used for the following operations (left to right):

You can configure the following parameters in the Warning Parameters dialog box:

1.	The condition that will trigger it. While specifying the conditions, keep in mind that some conditions cannot be used for some data types. For example, string values can be checked only if they are equal;

2.	The sound to play when this condition is met. Note that the sound can be played only when the condition is met for the first time or each time the tag changes and meets the condition.

Click the "OK" button to save the warning parameters. The warning will appear in the list after that.

To save the visualization block parameters, click the "OK" button in the Visualization Block Parameters dialog box. All changes will be applied after that.