3-9
3
In the 4807/4867, the Operation Condition Register reports the Local
Lockout and Remote GPIB interface states.
3.4.5
Output Queue
The Output Queue is used by the unit 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. 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 contents of the Output Queue clears
its summary bit. The Output Queue is read by addressing the 4807/4867 to
talk at its GPIB address. If the Output Queue is not read before sending
another query, its contents will be lost and an error reported. There is no
need to monitor the Output Queue bit as the user's program normally reads
responses after each query. The 2307/2367 automatically transmits the
response message to each query so the user does not have to do anything to
clear its Output Queue.
3.4.6
Status Byte Register
The unit sets bit 6 and generates a Service Request whenever any of the
enabled bits in the Status Byte Register become true (and the 4807/4867 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 160
'Sets the SRE Register to 1010 0000 which
enables just the Event Status and Question
able summary bits to generate a Service Request
Bit 6 of the Status Byte Register is cleared when the register is Serial Polled.
The register summary bits are cleared when the event register that drives
them is cleared by being read or with the *CLS command.
3.4.7
Saving the Enable and Transition Register Values
When the PSC flag is set, the Enable and Transition Register values are
cleared at power turn-on. The registers can only be saved and recalled at
power turn-on by disabling the PSC flag. The *SAV command does not
save these registers. Use the
*PSC 0
command to disable the PSC flag and