5.3 Unlocked and System Fault Indication
35
overruns. If the fault is severe enough, it may not be possible for the display to provide a reason
for the fault. Listed below are some of the possible reasons for a Fault LED switching ON.
Fault Listed
Indication, LEDs ON
Non-maskable interrupt error
Fault LED only
Stack overflow
Fault and Operate LED’s
Stack underflow
Fault and Timeset LED’s
Class B hardware error
Fault and Unlock LED’s
includes:
- Undefined Opcode
- Protected Instruction Fault
- Illegal Word Operand Access
- Illegal Instruction Access
- Illegal External Bus Access
Table 5.1: Fault Indications
If the fault is not severe enough to lock out use of the LCD display or keypad, the display will
indicate one of the faults listed in Table 5.1. These faults can normally be cleared by recycling
power to the Model 1133A. A severe fault, that cannot be cleared by recycling power, should be
immediately reported to Arbiter Systems technical support. If you do not see your fault listed here,
call the factory for assistance. See page ii for contact information.
