Specifications
User Manual 301/302 
Reading the Status 
Byte Register 
The Status Byte summary register can be read with the *STB? 
common query. The *STB? common query causes the generator to 
send the contents of the Status Byte register and the MSS (Master 
Summary Status) summary message as a single <NR1 Numeric 
Response Message> element. The response represents the sum of 
the binary-weighted values of the Status Byte Register. The *STB? 
common query does not alter the status byte. 
Clearing the Status 
Byte Register 
Removing the reasons for service from Auxiliary Status registers can 
clear the entire Status Byte register. Sending the *CLS command to 
the device after a SCPI command terminator and before a Query 
clears the Standard Event Status Register and clears the output 
queue of any unread messages. With the output queue empty, the 
MAV summary message is set to FALSE. Methods of clearing other 
auxiliary status registers are discussed in the following paragraphs. 
Service Request 
Enable Register 
(SRE) 
The Service Request enable register is an 8-bit register that enables 
corresponding summary messages in the Status Byte Register. Thus, 
the application programmer can select reasons for the generator to 
issue a service request by altering the contents of the Service 
Request Enable Register. 
The Service Request Enable Register is read with the *SRE? common 
query. The response to this query is a number that represents the sum 
of the binary-weighted value of the Service Request Enable Register. 
The value of the unused bit 6 is always zero. 
The Service Request Enable Register is written using the *SRE 
command followed by a decimal value representing the bit values of 
the Register. A bit value of 1 indicates an enabled condition. 
Consequently, a bit value of zero indicates a disabled condition. The 
Service Request Enable Register is cleared by sending *SRE0. The 
generator always ignores the value of bit 6. Summary of *SRE 
commands is given in the following. 
*SRE0 - Clears all bits in the register. 
*SRE1 - Not used. 
*SRE2 - Not used. 
*SRE4 - Not used. 
*SRE8 - Not used. 
*SRE16 - Service request on MAV. 
SCPI Command Reference 
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