Chapter 9. Diagnostics394 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual GFK-2950C9.3.2 Using Fault ContactsFault (-[F]-) and no-fault (-[NF]-) contacts can be used to detect the presence of I/O faults in thesystem. These contacts cannot be overridden. The following table shows the state of fault and no-fault contacts.Condition [F] [NF]Fault PresentFault AbsentONOFFOFFONAn NF contact will be ON (F contact will be OFF) when the referenced I/O point is not faulted, or thereferenced I/O point does not exist in the hardware configuration.Fault Locating References (Rack, Slot, Bus, Module)The PACSystems CPU supports reserved fault names for each rack, slot, bus, and module. Byprogramming these names on the FAULT and NOFLT contact instructions, logic can be executed inresponse to faults associated with configured racks and modules.Fault Locating Reference Name FormatThese fault names can only be programmed on the FAULT and NOFLT contacts. The reserved faultnames are always available. It is not necessary to enable a special option, such as point faults.FaultReference TypeReservedNameCommentRack #RACK_000r Where r is rack number 0 to 7.Slot #SLOT_0rss Where r is rack number 0 to 7 andss is slot number 0 to 31.Bus #BUS_0rssb(Genius only)Where r is rack number 0 to 7,ss is slot number 0 to 31, andb is the bus number (1 or 2).Module #M_rssbmmm(Genius only)Where r is rack number 0 to 7,ss is slot number 0 to 31,b is the bus number (1 or 2), andmmm is the Bus Address number 000 to 255.These fault names do not correspond to %SA, %SB, %SC, or to any other reference type. They aremapped to a memory area that is not user-accessible. Only the name is displayed.
