3-11
3
ties of the Operation Registers:
STAT:OPER:PTR 4
'
enables bit 2 to set on a posi-
tive transition of EDR F/F
STAT:OPER:NTR 2
'enables bit 1 to set on a nega-
tive transition of Status B
(Front panel local request)
STAT:OPER:ENAB 6
'enables Event bits 1 and 2
STAT:OPER:COND?
'quires the Operation Con
dition Register
3.4.5
Output Queue
The Output Queue is used by the 4863 to send IEEE 488.2 messages back
to the bus controller. These messages are responses to 488.2 and SCPI
queries sent to the unit by the bus controller and are normally read before
sending another command or query to the unit. The Output Queue reports
a '1' in bit 4 of the Status Byte Register when it contains a message(s) to be
read by the bus controller. Reading the Output Queue by addressing the
4863 to talk at its GPIB address clears the summary bit. If the Output Queue
is not read before sending another query, its contents will be lost and an error
reported.
3.4.6
Status Byte Register
The 4863 generates a service request, SRQ, (2363 generates a SRM)
whenever any of the enabled bits in the Status Byte Register become true
and the unit is not addressed as a talker. The Status Byte Register may be
read by a Serial Poll or with the
*STB?
query. The Status Byte Register is
enabled by setting the corresponding bits in the Service Request Enable
Register with the
*SRE
command. e.g.
*SRE 40
'Sets the SRE Register to 0010 1000 which en-
ables just the Event Status and Questionable
summary bits to generate SRQs.
