Racal Instruments 3155, User Manual

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User Manual 3155
Programming Reference 4-69
Reading the Status
Byte Register The Status Byte summary register can be read with the *STB? com-
mon query. The *STB? common query causes the generator to send
the contents of the Status Byte register and the MSS (Master Sum-
mary Status) summary message as a single <NR1 Numeric Re-
sponse 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 En-
able 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 gen-
erator to issue a service request by altering the contents of the Serv-
ice Request Enable Register.
The Service Request Enable Register is read with the *SRE? com-
mon 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. Conse-
quently, a bit value of zero indicates a disabled condition. The Serv-
ice Request Enable Register is cleared by sending *SRE0. The gen-
erator always ignores the value of bit 6. Summary of *SRE com-
mands 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.
*SRE32 - Service request on ESB summary bit.
*SRE128 - Not used.