Agilent Technologies E4406A VSA Series, Programmer'S Manual, Page: 73 / 420

Chapter 2 73
Programming Fundamentals
Using the Instrument Status Registers
You can monitor conditions in different ways.
• Check the current instrument hardware and firmware status.
Do this by querying the condition registers which continuously
monitor status. These registers represent the current state of the
instrument. Bits in a condition register are updated in real time.
When the condition monitored by a particular bit becomes true, the
bit is set to 1. When the condition becomes false, the bit is reset to 0.
• Monitor for the occurrence of a particular condition (bit).
Once you have enabled a bit, using the event enable register, the
instrument will monitor that particular bit. If the bit becomes true
in the event register, it will stay set until the event register is
cleared. Querying the event register allows you to detect that this
condition occurred even if the condition no longer exists. The event
register can only be cleared by querying it or sending the *CLS
command, which clears all event registers.
• Monitor any changes in a particular condition (bit).
Once you have enabled a bit, the instrument will monitor it for a
change in its condition. The transition registers are preset to
register the conditions going from 0 to 1, positive transitions. This
can be changed so that the selected bit is detected if it goes from true
to false (negative transition), or if either transition occurs.