Generator

4 min

Review the following information for setting up and configuring the Generator driver.

Litmus Edge Compatible Series

Compatibility parameter	Compatible items
Driver type	Used to generate simulated data
Validated devices/series	This driver is used to generate simulated data. It supports all the standard python math functions such as math.sin(X) and math.cos(X).

Configure the List of Registers

When you Add a TagAdd a Tag to the connected device, refer to the following register table and tag parameters.

Register Table

Name	Value Types	Address Format	Max Address	Description
bit	bit	DDD	255	boolean
int	int	DDD	255	integer
float	float	DDD	255	float

Tag Parameters

Name: Select a register name from the drop-down list. The available options depend on the names in the register table.

Value Type: Select a data type from the drop-down list. The available options depend on the register name selected.

Polling Interval: Enter a value in seconds. This determines how often the tag should poll the register for data.

Tag Name: Enter a name for the tag.

Description (Optional): Enter a description for the tag.

Address: Enter a tag address. The value must in the decimal format, within the allowed min/max range. Omit the leading zeros. The device might use the decimal (D), hexadecimal (H), or octal (O) address format. See the Register Table at the bottom of the dialog box. For Bit tags, append the bit address without the bit separator. The lowercase letters in the address format indicate how many digits you should enter in the Bit address.

Min value: Enter the minimum value the tag can generate.

Max value: Enter the maximum value the tag can generate.

Formula: Enter the formula for the tag.

Tag Formula: Enter a formula for the tag to process the generated data. Two variables are permitted: value (current tag value) and timestamp (current tag UNIX time in milliseconds). The following math functions are available:

sqrt

power: power(x) performs the operation 10^x.

log: log(x) is the natural logarithm (the logarithm is in base e).

exp: exp(x) performs the operation e^x.

Only Publish on Change of Value: Select the checkbox to customize NATS messages to be published only when the value parameter changes from a previous value to a new one. Change of Value only applies to boolean, numeric (such as int or float), and simple string data types. It does not apply to complex types, such as JSON or array. Poll-once topics will not be affected by Change of Value settings. These topics will still only see a single message.

Meta Data: Metadata summarizes basic information about data. This feature allows you to define key-value pair data for the device output payload later on. It can then be used to find, use, and reuse particular instances of data.

Note: If you use special characters in meta data key names, the special characters are replaced with underscore characters in the payload. This can cause two key names to be combined into one. For example, configuring the key names a**b and a&&b will cause only one key name to be created (a__b).

Tip:

All simulated tags have a default range of -50 to 50.

Users can override or restrict these defaults using a CSV upload.

Entering - in the MIN and MAX columns prevents the default constraints from being applied.

Numeric values in the MIN and MAX columns will replace the default settings.

The MIN and MAX constraints apply to the defined tag formula and do not affect Boolean tags.