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To use this tutorial, please do the following steps in advance:

• Install the NETx BMS ServerPlatform. The setup can be found here at our website.
• Create a new BMS server Platform workspace and integrate some data points that you want to monitor.

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First, we will create a new LUA function which verify the item value and sends an e mail if it is out of limit. Within the toolbar of the NETx BMS Core Studio, click on the "Edit Script" button.

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Afterwards, you can select the LUA file that you want to manipulate. Select "nxaDefinitions.lua" to open the main LUA file.

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function LimitValue(minValue, maxValue, email)

	local currentValue = nxa.SourceValue()

	if (currentValue ~= nil and currentValue >= minValue and currentValue <= maxValue)
   	then
		nxa.WriteDestinationValue(currentValue)
    else
		if (email ~= nil)
		then
			xcon.SendEmailTo(emailthen             nxa.XMail(Profile Name , email , "Value out of range", "The input value with ID " .. nxa.SourceItemID() .. " is out of range")
		end
	end
end

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If the condition evaluates to false, an e mail shall be sent if an e mail address is specified. First, it is verify whether an e mail is specified i.e. whether it is not nil. To send an e mail, the LUA function xcon.SendEmailTo(email, subject, body, attachment(optional)) is nxa.XMail is used. The first parameter is the e mail address Profile Name . In our example, it is provided by the third parameter of the LUA function LimitValue. The second third parameter is the subject of the e mail, the third forth the body, and the forth fifth is an optional file as attachment. The subject and body are strings. As body, LUA string concatenation using .. is used in order to include the Item ID that triggers the tasks using nxa.SourceItemID().

After having finished the LUA implementation, save LUA function and restart the LUA engine using the buttons within the toolbar of the LUA script editor.

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Configuring the e mail system

In order to send an e mail, the connection to an SMTP e mail server has to be configured. This is done within the System Parameter within the Server menu of the NETx BMS Studio. At the bottom of the configuration file, the SMTP host (IP address), SMTP port number and the authentication information (TLS, user name , password) have to entered. The following screenshot shows the configuration of the gmail SMTP server.

Image RemovedBMS Platform provides a new messenger module which can be used for creating new email profiles for different use, in the following article more info about how to create and configure E-Mail profile. 

Create a task definition to use the LUA function

What is still missing the usage of the LUA function. In order to trigger a LUA function whenever a data point changes its value, a Task can be used. To define a Task, open the "Task Definitions" within the "Extensions" menu of the NETx BMS Core Studio and create a definition. The column "Source Item ID" specified the item which shall trigger the LUA function. This means whenever the value of the item that is specified here is written, the task is trigger. The value of this item can be retrieved within LUA using the function nxa.SourceValue() – the item ID with the function nxa.SourceItemID(). The next column specified an optional destination item. The selected Item can be accessed within LUA using nxa.WriteDestinationValue(value) and nxa.DestinationItemID(). The next three columns are used to define when the task shall be trigger:

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The next column can be used to specify an optional delay. The column "Command" defines the action that shall be triggered by the task. To execute a LUA function "SCRIPT" has to be used. The last column "Parameter" finally defines the LUA function that shall be invoked when "SCRIPT" is used as command type. Here, the LUA function including the parameters have to be entered. In following screenshot shows how our LUA function LimitValue can be used to monitor the item NETx\VAR\Numeric\Item1. As destination item, NETx\VAR\Numeric\Item2 is used. 50 is used as lower limit and 100 as upper limit. The e mail address that shall be used is defined as third parameter. The second definition shows how the function can be used without using the e mail functionality.

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After having defined the your task, save the definition. Since the Task Definitions are live ones, they are automatically reloaded – a server restart is not necessary. Now test the new tasks. For the given example, set NETx\VAR\Numeric\Item1 to 70. Since it is between 50 and 100, the value 70 is also written to NETx\VAR\Numeric\Item2. If NETx\VAR\Numeric\Item1 is set to 40, an e mail is sent since the value is below the specified limit.

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