HP 34401A, User Manual

Page: 136 / 236

The Status Byte
The status byte summary register reports conditions from other status
registers. Query data that is waiting in the multimeter’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
The status byte summary register is cleared when:
•
You execute a
*CLS
(clear status) command.
•
Querying the standard event and questionable data registers will
clear only the respective bits in the summary register.
The status byte enable register (request service) is cleared when:
•
You turn on the power and you have previously configured the
multimeter using the
*PSC 1
command.
•
You execute a
*SRE 0
command.
The status byte enable register will not be cleared at power-on if you
have previously configured the multimeter using
*PSC 0.
Bit
0 Not Used
1 Not Used
2 Not Used
3 Questionable Data
4 Message Available
5 Standard Event
6 Request Service
7 Not Used
Decimal
Value
1
2
4
8
16
32
64
128
Definition
Always set to 0.
Always set to 0.
Always set to 0.
One or more bits are set in the Questionable Data
register (bits must be “enabled” in enable register).
Data is available in the multimeter’s output buffer.
One or more bits are set in the Standard Event
register (bits must be “enabled” in enable register).
The multimeter is requesting service (serial poll).
Always set to 0.
Chapter 4 Remote Interface Reference
The SCPI Status Model
136