# tChronometerStart
Operates as a chronometer device that starts calculating the processing time of one or more subJobs in the main Job, or that starts calculating the processing time of part of your subJob.
Starts measuring the time a subJob takes to be executed.
## tChronometerStart Standard properties
These properties are used to configure tChronometerStart running in the Standard Job framework.
The Standard tChronometerStart component belongs to the Logs & Errors family.
The component in this framework is available in all Talend products.
## Global Variables
| Variables | Description |
| --- | --- |
| Global Variables | STARTTIME: the start time to
calculate the processing time of subJob(s). This is a Flow variable and it returns a
long.
ERROR\_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error checkbox is
cleared, if the component has this checkbox.
A Flow variable functions during the execution of a component
while an After variable functions after the execution of the component.
To fill up a field or expression with a variable, press Ctrl+Space to access the variable list and choose the variable to use from
it.
For more information about variables, see [Using contexts and variables](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/contexts-and-variables). |
## Usage
| Usage guidance | Description |
| --- | --- |
| **Usage rule** | You can use tChronometerStart as
a start or middle component. It can precede one or more processing
tasks in the subJob. It can precede one or more subJobs in the main
Job. |