Specifications

3-6
Interrogating the Instrument Status
Status Byte Register Group
MSS bit is not cleared when the register is read using the *STB?
command. It always reflects the current status of all the
instrument’s status registers.
OPER Summary bit Operation Status register summary bit
Serial Polling
The Status Byte register can be interrogated by serial polling the instrument.
The command for serial polling is SPOLL, as shown in the example program lines below:
10 Status_value = SPOLL(718)
20 PRINT Status_value
The binary weighted decimal value returned in the variable Status_value is the value of
the Status Byte. The Status Byte gives a summary of the state of the reporting registers.
Another way of reading the value of the Status Byte is by using the *STB? common query
command:
10 OUTPUT 718;“*STB?”
20 ENTER 718;Status_value
In this case the value returned by the variable Status_value is exactly the same as the value
returned by carrying out a Serial Poll.
Status Byte Service Request Enable Register
The Service Request Enable register is an 8-bit register which acts as a mask on the Status
Byte. The Service Request Enable register is programmed using the SCPI common
command *SRE. When the register is programmed with any given value this determines
when the instrument will issue a service request. For a service request to be issued the
summary bit in the Status Byte must match the bit in the Service Request Enable Register.
SeeFigure3-3.
Figure 3-3 Status Byte Register