Agilent Technologies 34420A, User Manual

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The Status Byte
The status byte summary register reports conditions from other status
registers. Query data that is waiting in the meter’s output buffer is
immediately reported through the “message available” bit (bit 4). Bits in
the summary registers are
not latched. Clearing an event register will
clear the corresponding bits in the status byte summary register. Reading
all messages in the output buffer, including any pending queries, will
clear the message available bit.
Bit Definitions — Status Byte Register
Bit
Decimal
Value Definition
0 Not Used 1 Always set to 0
1 Not Used 2 Always set to 0
2 Not Used 4 Always set to 0
3 Questionable Data 8 One or more bits are set in the Questionable
Data register (bits must be "enabled" in the
enable register).
4 Message Available 16 Data is available in the meter output buffer
5 Standard Event 32 One or more bits are set in the Standard
Event register (bits must be "enabled" in the
enable register).
6 Request Service 64 The meter is requesting service (serial poll).
7 Operational Status 128 One or more bits are set in the Operational
Event register (bits must be "enabled" in the
enable register)
4
Chapter 4 Remote Interface Reference
The SCPI Status Model
161