Keithley 6487 Reference Manual page 277

C-14 DDC Emulation Commands
When an SRQ is generated by the Model 6487, bit 6 of the status byte will be set. After an
SRQ, the status byte will remain unchanged until it is read.
The various bits in the status byte are described below:
Reading Overflow (B0) — Set when an overrange input is applied to the instrument.
Cleared when on on-scale reading has been made.
Data Store Full (B1) — Set when the number of readings stored is equal to the buffer
size. Cleared by re-arming data store.
Data Store 1/2 Full (B2) — Set when the number of readings stored is equal to half the
buffer size. Cleared by re-arming data store.
Reading Done (B3) — Set when the instrument has completed the present conversion and
is ready to take another reading. Cleared when the reading has been sent.
Ready (B4) — Set when the instrument has processed all previous commands and is
ready to begin processing new commands or triggers. Cleared while instrument is process-
ing commands or triggers.
Error (B5) — Set when one of the following errors has occurred:
This bit is cleared when the U1 status word is read to determine the nature of the error (see
Figure
RQS (B6) — Set when the Model 6487 has generated a request for service via the SRQ
line. Cleared by reading the status byte.
– IDDC
– IDDCO
– No remote
– Self test
– Trigger overrun
– Conflict
– Cal locked
– Zero check
– Calibration error
2
– E PROM defaults error
2
– E PROM cal constants error
– V-source conflict
– Interlock
C-2.)
Model 6487 Reference Manual