User manual

Condition registers
As Figure 4-5 shows, all status register sets have a condition register. A condition register
is a real-time, read-only register that constantly updates to reflect the current operating con
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ditions of the instrument. For example, while a measurement is being performed, bit B4
(Meas) of the Operation Condition Register is set. When the measurement is completed, bit
B4 clears.
Use the :CONDition? query commands in the STATus Subsystem to read the condition
registers. See Section 5 for more information.
Event registers
As Figure 4-5 shows, each status register set has an event register. An event register is
a latched, read-only register whose bits are set by the corresponding condition register,
Once a bit in an event register is set, it remains set (latched) until the register is cleared by
a specific clearing operation. The bits of an event register are logically ANDed with the bits
of the corresponding enable register and applied to an OR gate. The output of the OR gate
is applied to the Status Byte Register.
Use the *ESR? Common Command to read the Standard Event Register. All other event
registers are read using the :EVENt? query commands in the STATus Subsystem. See Sec
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tion 5 for more information.
An event register is cleared when it is read. The following operations clear all event reg-
isters:
• Cycling power
• Sending *CLS
2000-900 (J - Aug 2010) BOOK.fm Page 20 Wednesday, October 12, 2011 12:29 PM