GE GFK-0787B user manual Synchronous or Asynchronous Input Autotest and I/O Shutdown

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I/O Shutdown

When the GMR system diagnoses a discrete I/O fault, it logs the appropriate faults in its fault tables and set the appropriate fault contacts. For certain types of discrete I/O faults, the system optionally allows a predefined amount of time for the problem that caused the fault to be repaired. If the problem is not rectified within this period of time, an I/O Shutdown of the I/O corresponding to the affected block(s) occurs. I/O shut down can be completely disabled and prevented by turning on the Cancel I/O Shutdown control bit (%M12265).

I/O Shutdown is defined as setting the affected I/O to its safe state. For outputs, this is the Off state. For discrete inputs, the shutdown state is the ªdefaultº state for an input group in the GMR configuration. This can be selected on an input group basis.

Synchronous or Asynchronous Input Autotest and I/O Shutdown

In the GMR configuration discrete input groups can be configured for either

Synchronous or Asynchronous input autotesting.

If redundant discrete input devices are used, which allows the individual blocks in a group to stay isolated from each other (I.E. the power feed outputs (point 16) of each block ARE NOT wired together), asynchronous input autotesting can be selected.

Asynchronous input autotesting can also be selected if non-redundant simplex discrete input devices are used with isolation between blocks. Using this option allows the input autotest to continue executing on other blocks in a group which are not affected by the fault. Because input autotesting continues in this case, an I/O shutdown is not necessary and WILL NOT occur. (See Chapter 8 ± installation information)

Blocks Wired Together Blocks Not Wired Together

If non±redundant simplex discrete input devices are used without isolation between blocks (I.E. the power feed outputs (point 16) of each block ARE wired together), then synchronous input autotesting must be selected in the GMR configuration for the input group. (See Chapter 8 ± installation information)

For this configuration there are two types of faults which may prevent the autotest from continuing to execute for that input block group and thus cause a I/O shut down for the inputs in the group:

1.) Loss of a block within the group. (I.E. any failure which causes the block to no longer communicate on the Genius Bus such as loss of power.)

2.) Autotest failure of the power feed output (point Q16) of any of the blocks in a group.

4-18	GeniustModular Redundancy Flexible Triple Modular Redundant (TMR) System	GFK-0787B
	User's Manual ± March 1995