Rockwell-automation 1794-L34 FlexLogix Controller System User Manual Manual do Utilizador descarregar pdf (Página 82)

Publication 1794-UM001G-EN-P - January 2007

82 Develop Applications

4. Develop a routine for the Controller Fault Handler. See the

Logix5000 Controllers Common Procedures, publication

1756-PM001.

Select a System

Overhead Percentage

The Controller Properties dialog lets you specify a percentage for

system overhead. This percentage specifies the percentage of

controller time (excluding the time for periodic tasks) that is devoted

to communication and background functions.

System overhead functions include:

• communicating with programming and HMI devices (such as

RSLogix 5000 software)

• responding to messages

• sending messages

• re-establishing and monitoring I/O connections (such as RIUP

conditions); this does not include normal I/O communications

that occur during program execution

• bridging communications from the serial port of the controller to

other communication devices

The controller performs system overhead functions for up to 1 ms at a

time. If the controller completes the overhead functions in less than

1 ms, it resumes the continuous task.

As the system overhead percentage increases, time allocated to

executing the continuous task decreases. If there are no

communications for the controller to manage, the controller uses the

communications time to execute the continuous task. While increasing

1. View properties for the controller and select the Advanced tab.

1 2 ... 77 78 79 80 81 82 83 84 85 86 87 ... 129 130

Sem comentários

Rockwell-automation 1794-L34 FlexLogix Controller System User Manual Manual do Utilizador Página 82