# i4connected Knowledgebase 5.6

### Signals Management

Abstract

Learn how to manage the i4connected Signals. All that you need to know about adding, editing, deleting Signals, and much other information!

At the level of i4connected, managing Signals can be a complex operation. To provide a simple explanation of the terminology itself, the scope of signals is to identify timestamp associated measurements (data points) registered by a device. The i4connected Signals can establish multiple use cases, depending on the plant needs.

Based on the i4connected signals workflow, there are two separate denominations:

• Signal definition - the abstract definition of the signal, consisting of a signal name, description, alias, type, and other advanced settings such as conversion, dead-band, plausibility delta, interpolation, gap, and inactivity intervals.

• Signal value (measurement) – the actual manifestation of a signal, consisting of a value – timestamp pair.

Each signal is individually logged. All its measurements are stored in that log and reused for further analysis purposes.

Based on their value-timestamp measurements, we can distinguish two Signal categories:

• Counter value Signals – involved in consumption measurements.

e.g. – an energy consumption counter is read periodically and the measurement is calculated by deducting the current value from the initial value.

• Absolute value Signals – are regular data points that represent various values such as temperature, instant consumption, voltage, etc. Anything that is not a counter falls in this category.

e.g. – the recorded measured values are automatically reused to calculate KPIs.

Signals can be managed in the context of the i4connected Devices, by clicking the Signals tile from the View Device panel, by all users having at least the View sites and View devices permission enabled.

Opening the Signal List panel

### Tip

The Signal List panel displays all the Signals assigned to the selected Device, providing the user with the following options:

The Signal List panel

In this view, the user must provide the required (and optional) signal settings and click the Save button to add the signal to the device's signals list. The signal settings are split into the following categories:

Category

Setting

Description

Standard settings

Name

The PLC name of the signal

Alias

The friendly name of the signal

Description

The description of the signal

GPS

GPS

Enables the Signal as GPS Signal, if the toggle button is set to Yes.

### Tip

For more details about the GPS Signals, please also visit the dedicated article, here.

Counter settings

Counter value

The initial value of the counter. Setting this activates the signal as a counter signal.

Counter overflow

The max value of the counter signal. When the counter reaches this value and starts over, the difference is still calculated correctly. If set to 0, no alarm is raised when reaching the overflow value.

Signal type

The type of the signal, defined in the i4connected portal.

By clicking this field, the Signal Types panel is opened, allowing the user to select the desired type.

Used independently, an i4connected Signal Type is a label providing additional information about a Signal. The Signal Type can be used in a Key Performance Indicator (KPI) formula, hence providing more advanced measurement methods.

Signal Types are also involved in i4SCADA visualizations, providing information for the associated Units of Measure (UoM) giving meaning to the signal. e.g. - Electrical energy, Water, Gas, Heating, etc.

Use Absolute Value

Returns the absolute value of a number. In other words: the Use Absolute Value function removes the minus sign (-) from a negative number, making it positive.

Factor

The multiplication factor for the signal value. Used to transform the signal value into meaningful analysis value.

Conversion factor

Similar to the Factor, the Conversion factor is used to further transform the signal value. The Factor and Conversion factor don't exclude each other.

Minimum value / Maximum value

Sets the Min / Max interval for the accepted value updates.

For example, having the Minimum value set to 10 and the Maximum value set to 100, a new value that is lower than 10 and another one, higher than 100, will be rejected.

The value when the signal is idle.

### Tip

The deadband time is measured in Minutes, Seconds, and Milliseconds.

Plausibility delta

The maximum difference between two consecutive values for which the values are considered plausible. Exceeding this difference will trigger an alarm.

### Tip

For more details about the Plausibility delta feature, please also visit the article here.

Gap interval

The maximum time span between two consecutive values. When this time span is exceeded, an alarm is triggered. If Interpolation is enabled, exceeding this Gap interval triggers the Interpolation.

### Tip

For more details about the Gap detection feature, please also visit the article here.

Insert Gap interval

The Gap interval is measured in Days, Hours, and Minutes.

Enable Interpolation

If enabled, the system interpolates the values when a gap is detected between two consecutive values.

### Tip

For more details about the Interpolation feature, please also check the article here.

Inactivity Interval

The time interval between two consecutive updates, measured in Days, Hours, and Minutes.

Measurement handling

Log data points

If enabled, the system logs the signal values, both raw values and end values (after Factor and Conversion factor)

Stream data points

If enabled, the logged values are streamed through the query engine.

Compression settings

Deviation

Is the most significant compression parameter, representing the half-width of the deviation blanket. The deviation blanket is extended between the last recorded value and the new value, with a width equal to twice the compression deviation specification. The Compression Deviation can be expressed as floating-point values, by manual input.

Minimum TimeInterval

The compression minimum time has as scope to prevent highly demanding values from using a large amount of archive space. For example, a new log is not recorded if the time since the last recorded event is less than the compression minimum time for the point. The timestamp for minimum compression interval can be defined in minutes, seconds, and milliseconds.

Maximum TimeInterval

The compression maximum time is usually set to one value that covers all points in the system. It should be large enough that a point that does not change at all, uses very little archive space. For example, a compression maximum time of one work shift (8 hours) is often a good choice. The timestamp for maximum compression interval can be defined in minutes, seconds, and milliseconds.

Sets the "Read access" security setting of SCADA Signals, choosing from the drop-down list items: Deny, AllowUnsecured, and AllowSecured.

Write access

Sets the "Write access" security setting of SCADA Signals, choosing from the drop-down list items: Deny, AllowUnsecured, and AllowSecured.

### Note

The fields marked with bold characters are required in order to add a new signal.

For more details concerning the Device-specific signal settings, please also visit the article here.

A Virtual Signal is a signal that doesn't receive values from a device but generates them based on a defined formula (or expression). Virtual Signals are defined on the devices just like normal signals but require some additional settings.

Virtual Signals can be managed by users having the Manage virtual signals permission enabled at the global level.

### Warning

Without this permission, the user can only see the Virtual devices in the Signal list panel as grayed-out entities.

Example of a grayed out virtual signal

Virtual Signals share most of their properties with the normal signals (see the above table) but they also expose their specific settings.

Category

Setting

Description

Standard settings

Name

The name of the virtual signal

Alias

The friendly name of the virtual signal

Description

The description of the virtual signal

Virtual signal configuration

Parameters

Allows the user to input signals that can be used in the formula to calculate the expected values. To add a new parameter, the user can click the Add parameter button which opens the Signal List panel allowing the user to select a signal to act as input for the formula. The parameters can be either a standard signal or another virtual signal. A virtual signal supports multiple parameters of mixed types (standard signals and virtual signals).

Once a parameter is defined, it will be displayed in the table below the Add parameter button. Here the user is able to set the name of the parameter (which will be used inside the formula) and input a test value, allowing the user to test the virtual signal’s formula.

The Parameters area

Formula

The expression is used to calculate the value of the virtual signal.

The expression can use input parameters defined in the Parameters options. The expression can be a simple online calculation or can be a complex, multi-line C# function enclosed in curly brackets {}, in which case a return function is required. The advantage of using complex C# expressions is the availability of variables, loops, etc.

Simple expression example:

in1 > 10

Multi-line expression example:

var calculatedValue = in1 + 10;
if (calculatedValue > 20) {
return true;
} else {
return false;
}

When using parameters in your expression, you are not limited only to the value of that parameter. Several properties of the signal used as input parameters can also be used inside the expression:

• Delta (double), ex: in1.Delta

• Interpolated (bool), ex: in1.Interpolated

• Plausible (bool), ex: in1.Plausible

• Timestamp (DateTime), ex: in1.Timestamp

• Value (object), ex: in1.Value

• Counter (double), ex: in1.Counter

For example:

var signalDelta = in1.Delta;
if (signalDelta > 20) {
return 1;
} else {
return 0;
}

The below list illustrates the logical operators that can be used when writing virtual signals expressions:

• > - higher

• < - smaller

• >= - higher or equal

• <= - smaller or equal

• == - equal

• != - different

• && - and

• || - or

• ~ - Bit-wise NOT

• ^ - Bit-wise XOR

• & - Bit-wise AND

• | - Bit-wise OR

The value returned by the expression can be of any type, as you can notice in the two examples above.

The formula can be tested using the Calculate test result button. This will use the parameter's test value as input value and the result will be listed below.

The parameters Formula

Computation Mode

The method of using the parameter values.

• Historical script - uses the values already existing in the database. The virtual signal is updated whenever a timestamp match is found in the database and uses the corresponding value for the input parameter. The maximum virtual signal update rate is limited to 15 minutes.

• Online script - uses the online values of the input parameters. The virtual signal is updated whenever the input parameter signal is updated, and the new value of the input parameter is used in the virtual signal's formula.

Counter settings

Counter

Setting this activates the signal as a counter signal.

Counter value

The initial value of the counter.

Counter overflow

The max value of the counter signal. When the counter reaches this value and starts over, the difference is still calculated correctly. If set to 0, no alarm is raised when reaching the overflow value.

Signal type

The type of the signal, defined in the i4connected portal.

By clicking this field, the Signal Types panel is opened, allowing the user to select the desired type.

Used independently, an i4connected Signal Type is a label providing additional information about a Signal. The Signal Type can be used in a Key Performance Indicator (KPI) formula, hence providing more advanced measurement methods.

Signal Types are also involved in i4SCADA visualizations, providing information for the associated Units of Measure (UoM) giving meaning to the signal. e.g. - Electrical energy, Water, Gas, Heating, etc.

Use Absolute Values

Returns the absolute value of a number. In other words: the Use Absolute Value function removes the minus sign (-) from a negative number, making it positive.

Factor

The multiplication factor for the signal value. Used to transform the signal value into meaningful analysis value.

Conversion factor

Similar to the Factor, the Conversion factor is used to further transform the signal value. The Factor and Conversion factor don't exclude each other.

Minimum value / maximum value

Sets the Min / Max interval for the accepted value updates.

For example, having the Minimum value set to 10 and the Maximum value set to 100, a new value that is lower than 10 and another one, higher than 100, will be rejected.

The value when the signal is idle.

### Tip

Plausibility delta

The maximum difference between two consecutive values for which the values are considered plausible. Exceeding this difference will trigger an alarm.

### Tip

For more details about the Plausibility delta feature, please also visit the article here.

Gap interval

The maximum time span between two consecutive values. When this time span is exceeded, an alarm is triggered. If Interpolation is enabled, exceeding this Gap interval triggers the Interpolation.

### Tip

For more details about the Gap detection feature, please also visit the article here.

Insert Gap interval

The Gap interval is measured in Days, Hours, and Minutes.

Interpolation active

If enabled, the system interpolates the values when a gap is detected between two consecutive values.

### Tip

For more details about the Interpolation feature, please also check the article here.

Insert inactivity interval

The time interval between two consecutive updates, measured in Days, Hours, and Minutes.

Measurement handling

Log data points

If enabled, the system logs the signal values, both raw values and end values (after Factor and Conversion factor)

Stream data points

If enabled, the logged values are streamed through the query engine.

Security

Sets the "Read access" security setting of SCADA Signals, choosing from the drop-down list items: Deny, AllowUnsecured, and AllowSecured.

### Note

The settings marked with bold characters are required in order to add a new virtual signal.

The GPS Signals are used to supply GPS coordinates into the WEBfactory system. Based on the provided GPS coordinates, WEBfactory operators can track mobile device movements, in order to easily establish when a device exits or enters a target area.

GPS Signals are defined in the context of devices, just like normal signals, but with a slightly different set of properties.

### Important

Virtual Signals can not be set as GPS Signals.

Category

Setting

Description

Standard settings

Name

The name of the Signal.

Alias

The friendly name of the Signal.

Description

The description of the Signal.

GPS

GPS

Enables the Signal as GPS Signal, if the toggle button is set to Yes.

Device-specific Signal settings

List of Device specific Signal settings

Based on the Device to which the new GPS Signal is assigned, a set of Device specific Signal settings can be available.

### Tip

For more details, please also visit the dedicated article, here.

The time Deadband is measured in Minutes, Seconds, and Milliseconds. The purpose of the Time Deadband setting is to insert a minimum interval of time to wait before storing the new values and considering them as updates. All the values that are updated during this interval will be ignored and considered as unnecessary noise.

### Tip

For more details, please also visit the dedicated article, here.

Security

Sets the "Read access" security setting of SCADA Signals, choosing from the drop-down list items: Deny, AllowUnsecured, and AllowSecured.

Write access

Sets the Write access security setting of SCADA Signals, choosing from the drop-down list items: Deny, AllowUnsecured, and AllowSecured.

### Note

The fields marked with bold characters are required in order to add a new GPS Signal.

#### Editing Signals

Clicking on a signal in the Signal list panel opens the Edit Signal panel allowing the user to edit the signal information (standard settings, device-specific settings as well as parameters, formula, and calculation mode for virtual signals, as described by the previous article.

The Edit signal panel

The Edit signal panel features the User toolbar button which enables the possibility to assign user roles to a Signal.

The Signal role assignments panel

### Tip

For more details about the Entity role assignments feature, please also visit the dedicated article.

Further on, the Signal's online value is also listed when opening a Signal in edit mode. The Online value of a Signal can only be seen by users having at least the Read signals permission enabled.

Signal's Online value

Users having the Write signals permission enabled can process further advanced signal value operations, such as:

#### Deleting Signals

The toolbar of the Edit signal panel also features the Delete button, allowing users with Write signals permission enabled to remove redundant Signals.

The Delete measurements panel displays a list of consequences involved by the deletion operation (the amount of deleted measurements, events, and signal scripts).

The Delete measurements panel

A confirmation code is requested in this view. In case the typed deletion code is incorrect, the system will warn the user and prevent the deletion operation. After manually typing the correct deletion code and pressing the Delete button, the adapter will be permanently removed.