Publication No. 980935 Rev. A
3152B User Manual
EADS North America Test and Services
Programming Reference 5-117
clear the corresponding bits in the Status Byte summary register.
Description of the various bits within the Status Byte summary register
is given in the following:
Bit 0
- Decimal value 1. Not used, always set to 0.
Bit 1
- Decimal value 2. Not used, always set to 0.
Bit 2
- Decimal value 4. Not used, always set to 0.
Bit 3
- Decimal value 8. Not used, always set to 0.
Bit 4
- Decimal value 16. Message Available Queue Summary
Message (MAV). The state of this bit indicates whether or not the
output queue is empty. The MAV summary message is true when
the output queue is not empty. This message is used to
synchronize information exchange with the controller. The
controller can, for example, send a query command to the device
and then wait for MAV to become true. If an application program
begins a read operation of the output queue without first checking
for MAV, all system bus activity is held up until the device
responds.
Bit 5
- Decimal value 32. Standard Event Status Bit (ESB)
Summary Message. This bit indicates whether or not one or more
of the enabled ESB events have occurred since the last reading
or clearing of the Standard Event Status Register.
Bit 6
- Decimal value 64. Master Summary Status (MSS)/Request
Service (RQS) Bit. This bit indicates if the device has at least one
condition to request service. The MSS bit is not part of the IEEE-
STD-488.1 status byte and will not be sent in response to a serial
poll. However, the RQS bit, if set, will be sent in response to a
serial poll.
Bit 7 - Decimal value 128. Not used, always set to 0.
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
The Service Request enable register is an 8-bit register that enables
corresponding summary messages in the Status Byte Register. Thus,
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
