Keithley 2002, User Manual

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IEEE-488 Reference
3-117
3.20 :STATus subsystem
The STATus subsystem is used to control the status registers of the Model 2002. These registers
and the overall status structure is explained in paragraph 3.7. The commands in this subsystem
are summarized in Table 3-12.
[:EVENt]?
:STATus:MEASurement[:EVENt]? Read Measurement Event Register
:STATus:QUEStionable[:EVENt]? Read Questionable Event Register
:STATus:OPERation[:EVENt]? Read Operation Event Register
:STATus:OPERation:TRIGger[:EVENt]? Read Trigger Event Register
:STATus:OPERation:ARM[:EVENt]? Read Arm Event Register
:STATus:OPERation:ARM:SEQuence[:EVENt]? Read Sequence Event Register
These query commands are used to read the event registers. After sending one of these com-
mands and addressing the Model 2002 to talk, a decimal value is sent to the computer. The
binary equivalent of this value determines which bits in the appropriate register are set. The
event registers are shown in Figures 3-21 through 3-26. Note that reading an event register clears
the bits in that register.
For example, assume that reading the Measurement Event Register results in an acquired deci-
mal value of 544. The binary equivalent is 0000001000100000. For this binary value, bits B5
and B9 of the Measurement Event Register are set.
The significance of a set bit in these registers depends on how the transition filter is programmed
(see :PTRansition and :NTRansition commands). If an event is programmed for a positive tran-
sition (PTR), the corresponding bit in this register sets when the event occurs. If the event is
instead programmed for a negative transition (NTR), the bit sets when the event becomes not
true.
Measurement Event Register:
Bit B0, Reading Overflow (ROF) — Set bit indicates that the reading exceeds the measurement
range of the instrument (PTR), or the instrument has gone from an overflow condition to a nor-
mal reading condition (NTR).
Bit B1, Low Limit 1 (LL1) — Set bit indicates that the reading is less than the Low Limit 1
setting (PTR), or that a subsequent reading is no longer less than the Low Limit 1 setting (NTR).
Bit B2, High Limit 1 (HL1) — Set bit indicates that the reading is greater than the High Limit
1 setting (PTR), or that a subsequent reading is no longer greater than the High Limit 1 setting
(NTR).
Bit B3, Low Limit 2 (LL2) — Set bit indicates that the reading is less than the Low Limit 2
setting (PTR), or that a subsequent reading is no longer less than the Low Limit 2 setting (NTR).
Bit B4, High Limit 2 (HL2) — Set bit indicates that the reading is greater than the High Limit
2 setting (PTR), or that a subsequent reading is no longer greater than the High Limit 2 setting
(NTR).
Bit B5, Reading Available (RAV) — Set bit indicates that a reading was taken and processed
(PTR), or that a subsequent reading is in process (NTR).
Bit B6 — Not used.
3.20.1
Description