VFC compute hours overview and recommendations¶

The compute hours used by Visual Flow Creator (VFC) flows can vary. Actual usage may differ from estimates or past values. VFC is a cloud-based automation tool. The compute time depends on several factors. These factors are not always predictable or controlled by Siemens.

Factors affecting compute hour usage¶

The following factors influence compute hour consumption:

• External network requests: Flows that use HTTP Request nodes depend on external services. Response times from these services can vary and affect execution time.
• Internal service response times: Operations such as writing time-series data (for example, using Write Timeseries nodes) may experience delays. These delays depend on system load and processing conditions.
• Inbound HTTP traffic: Flows triggered through HTTP In nodes depend on external calls. Higher request frequency increases compute hour usage.
• Shared infrastructure performance: VFC runs on shared cloud infrastructure. This includes databases, caching, and orchestration services. Performance and availability may impact flow execution time and resource usage.

Recommendations¶

• Monitor flow activity and compute usage regularly in VFC.
• Design flows to be efficient.
• Reduce unnecessary external calls where possible.
• Optimize flow logic to minimize execution time.

Example¶

The following examples shows:

• This flow sends an email notification in 200ms.

  

• This flow reads the timeseries data to check the last value and writes the new value in 400ms.

  

• This flow shows the "wait time" will not be charged. 200ms + 300ms = 500ms. In this flow insert delay nodes will split the flow execution into two parts. Each execution will be charged.

  

• This flow runs until the Timeout of 30.03 seconds is reached. Rounded down the compute hours are charged for 30 seconds.

  

• This flow can optimize the execution time of "multiple" flows using only one inject node in 800ms will be charged for the execution of the displayed flow.