CycleLoad

General

Functional Description

The parameter CycleLoad indicates the utilized capacity [%] of the PacDrive controller by the real-time process. The value of the parameter should not exceed 40-50 % on average. The remaining 50-60 % are then available for the other system functions such as the fieldbus server, network, and the program. Individual brief peaks are not a problem. Diagnostic message 8511 "CPU time overflow" is sent when 100 % is reached. Data loss is likely in this case.

 CycleLoad is a simple and clear variable for evaluating the system load.

Relationship between CycleLoad and WriteRes

 

 

The real-time process (RTP) is the most important system task. It is responsible for executing 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 three main steps.

Step 1 (Blue)

oPreparation of the cycle

oInitializing of measuring variables and monitoring

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

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

oThe logical encoders, Sum encoder (SLAVE_ENCODERS (LEnc, Summ, MSumm))

oThe axes

oPerform diagnostics status

oStatus machine of the drives

oReal-time job preparation

oPOS and CAM generators (master and slave curves)...

oNew reference values are now available

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

oThe reference values are transferred for transmission in the next cycle

Step 2 (Grey)

The remaining real-time functions, such as

oTouchprobe

oTrace, and so on.

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