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Relay Matrix Switch Command Reference 55
Chapter 3
STATus
The STATus subsystem reports the bit values of the Operation Status
Register (in the command module). It also allows you to unmask the bits
you want reported from the Standard Event Register and to read the
summary bits from the Status Byte register.
Subsystem Syntax
STATus
:OPERation
:CONDition?
:ENABle <unmask>
:ENABle?
[:EVENt?]
:PRESet
The STATus system contains four software registers that reside in a
SCPI driver, not in the hardware (see Figure 3-1) Two registers are under
IEEE 488.2 control: the Standard Event Status Register (*ESE?) and the
Status Byte Register (*STB).
The Operational Status bit (OPR), Service Request bit (RSQ), Standard
Event summary bit (ESB), Message Available bit (MAV) and
Questionable Data bit (QUE) in the StatusByte Register (bits 7, 6, 5, 4
and 3 respectively) can be queried with the *STB? command.
Use the *ESE? command to query the unmask value for the Standard
Event Status Register (the bits you want logically OR’d into the summary
bit). The registers are queried using decimal weighted bit values. The
decimal equivalents for bits 0 through 15 are included in Figure 3-1.
A numeric value of 256 executed in a STATus:OPERation:ENABle
<unmask> command allows only bit 8 to generate a summary bit. The
decimal value for bit 8 is 256.
The decimal values are also used in the inverse manner to determine
which bits are set from the total value returned by an EVENt or
CONDition query. The SWITCH driver exploits only bit 8 of Operation
Status Register. This bit is called the Scan Complete bit which is set
whenever a scan operation completes. Since completion of a scan
operation is an event in time, bit 8 will never appear set when
STAT:OPER:COND? is queried. However, bit 8 is set with the
STAT:OPER:EVENt? query command.