GE 90-30/20/Micro manual Fault Actions, Fault Action Response by CPU

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Fault Action

Faults may be fatal, diagnostic or informational.

Fatal faults cause the fault to be recorded in the appropriate table, any diagnostic variables to be set, and the system to be halted. Diagnostic faults are recorded in the appropriate table, and any diagnostic variables are set. Informational faults are only recorded in the appropriate table.

Possible fault actions are listed in the following table.

Table 3-2. Fault Actions

Fault Action

Response by CPU

Fatal	Log fault in fault table.
	Set fault references.
	Go to STOP mode.
Diagnostic	Log fault in fault table.
	Set fault references.
Informational	Log fault in fault table.

When a fault is detected, the CPU uses the fault action for that fault. Fault actions are not configurable in the Series 90-30 PLC, Series 90-20, or the Series 90 Micro PLC.

Fault References

Fault references in the Series 90-30 are of one type, fault summary references. Fault summary references are set to indicate what fault occurred. The fault reference remains on until the PLC is cleared or until cleared by the application program.

An example of a fault bit being set and then clearing the bit is shown in the following example. In this example, the coil light_01 is turned on when an oversweep condition occurs; the light and the OV_SWP contact remain on until the %I0359 contact is closed.

ov_swplight_01 ——] [————————————————————————————————————————————————————————————————————( )—

%I0359ov_swp ——] [————————————————————————————————————————————————————————————————————(R)—

3-4 Series 90-30/20/Micro Programmable Controllers Reference Manual–September 1998 GFK-0467K