Response Electronics CL6011B Specifikace stáhnout pdf (Strana 80)

3Ć60 Theory of Operation: Self Test

Original Ć June 1990

CE4.2:CL6211

3.7.4 Discrete Input Output Self Test

The discrete input output self test simply performs a check on the input

output driver device setup, and is incapable of validating the discrete

input output circuitry itself. Any alteration to the setup of the discrete

input output driver device is reported as a discrete input output self test

error.

3.7.5 Communications Error Rate Excessive Self Test

Incoming communications messages are checked for parity, framing,

and overrun errors. Any sustained communications error rate greater

than 5 percent will cause an error to be signalled.

3.7.6 Function Sequence Table (FST) Overload Self Test

Checks are performed to determine if the control task (the Function

Sequence Table, or FST) has completed in its allotted time, normally

one-quarter second. If the control FST does not complete within

one-quarter second, and this condition is sustained for more than

several executions, an FST overload error condition will be signalled.

This indicates that the controller configuration load, and the associated

communications load that the controller is required to support, is too

great for the controller to complete within the window of time of

one-quarter second. The user must take action to correct this situation.

See section NO TAG on page NO TAG which describes the trade-offs

between communications and control, and how to deal with reducing the

controller load imposed by each of these.

3.7.7 Free Time Computation

The controller performs a background computation to determine how

much idle time is available. Idle time, or free time, refers to the time

where there are no tasks scheduled to be performed by the controller.

A controller with no configuration, and a minimum of communications

support, will normally report 100 percent free time. The only operations

being performed by the controller under these conditions are the

overhead scheduling operations, and the controller internal self test

tasks. The percent of free time is a value that is reported on the

controller diagnostic displays.

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Response Electronics CL6011B Specifikace Strana 80