CycleLoad

General

Type

AF

Devices supporting the parameter

PacDrive LMC x00C,

PacDrive LMC x01C

Traceable

Yes

Functional Description

The parameter CycleLoad indicates the used capacity [%] of the PacDrive controller by the real-time process. Generally, it is a good practice to keep the cycle load to a value that allows for some overhead processing for tasks such as fieldbus server, network communications and other program related tasks. Usually, peak loads of short durations do not pose a significant degradation of performance. However, if there is insufficient overhead reserved for tasks performed outside of the cycle, you could receive a diagnostic message. This condition could result in the loss of data.
NOTICE
LOSS OF DATA
Ensure that your cycle timing allows for processing that occurs outside of the cycle.
Failure to follow these instructions can result in equipment damage.

CycleLoad is a variable for evaluating the system load.

Relationship between CycleLoad and WriteRes

The real-time process (RTP) is an important system task. It enables the execution of the real-time tasks at the correct time. Real-time processing is triggered by the Sercos real-time bus during each bus cycle. Processing is then performed in the following steps.

Step 1 (Blue)

  • Preparation of the cycle

  • Initializing of measuring variables and monitoring

  • Acceptance of the real-time data provided by the most recent drive telegrams (DTs) of the Sercos slaves

  • Processing of the master encoders such as Virt. Master Encoder and physical master encoders (Venc, PhyEnc, and Inc)

  • The logical encoders, Sum encoder (SLAVE_ENCODERS (LEnc, Summ, MSumm))

  • The axes

    • Perform diagnostics status

    • Status machine of the drives

    • Real-time job preparation

    • POS and CAM generators (master and slave curves)...

    • New reference values are now available

    • The data is transmitted in the master data telegram (MDT) in the next cycle

  • The reference values are transferred for transmission in the next cycle

Step 2 (Grey)

The remaining real-time functions, such as

  • Touchprobe

  • Trace, and so on.

Certain externally event-controlled tasks and also high-priority can adversely affect the execution of the real-time process. Monitoring the variables CycleLoad, RTBReadRes, and RTBWriteRes allows the evaluation of the dynamic behavior.