Remote Interface Reference 3Keysight E364xA User’s and Service Guide 131The status byte summary register is cleared when:– you execute the *CLS (clear status) command.– Querying the Standard Event register (*ESR? command) will clear only bit 5 inthe Status Byte summary register.For example, 24 (8 + 16) is returned when you have queried the status of theStatus Byte register, QUES and MAV conditions have occurred.The Status Byte Enable register (Request Service) is cleared when:– You execute the *SRE 0 command.– You turn on the power and have previously configured the power supply usingthe *PSC 1 command.The enable register will not be cleared at power-on if you have previouslyconfigured the power supply using *PSC 0.Using Service Request (SRQ) and serial POLLYou must configure your bus controller to respond to the IEEE-488 service request(SRQ) interrupt to use this capability. Use the Status Byte enable register (*SREcommand) to select which summary bits will set the low-level IEEE-488 servicerequest signal. When bit 6 (request service) is set in the Status Byte, an IEEE-488service request interrupt message is automatically sent to the bus controller. Thebus controller may then poll the instruments on the bus to identify which onerequested service (the instrument with bit 6 set in its Status Byte).The request service bit is cleared only by reading the Status Byte using anIEEE-488 serial poll or by reading the event register whose summary bit is causingthe service request.To read the Status Byte summary register, send the IEEE-488 serial poll message.Querying the summary register will return a decimal value which corresponds tothe binary-weighted sum of the bits set in the register. Serial poll willautomatically clear the “request service” bit in the Status Byte summary register.No other bits are affected. Performing a serial poll will not affect instrumentthroughput.
