Status Byte Format - Keithley 705 Instruction Manual

U8 - Sending the U8 command outputs the programmed
first and last channel. The programmed first and last
channel can be sent with or without a prefix depend-
ing on the present prefix mode (G). Refer to the flow-
chart in Figure 3-6 for the sequence of sending the U
and G modes. Refer to paragraph 3.5.8 step 7 for
information concerning the prefix modes and their
formats.
1
00 NOT SEND
PREFIX
OUTPUT
Figure 3-6. U and G Modes Sequence
3.6 STATUS BYTE FORMAT
The status byte contains information relating to data and error
conditions within the instrument. The controller obtains the status
byte by using the serial polling sequence (SPE) described para-
graph 3.4.2. Once the byte resides in the computer, the informa-
tion in Figure 3-7 can be used when interpreting data and error
conditions.
Bit six is the SRQ bit. If this bit is set the service request was
made by the Model 705. Bit five determines the meaning of bits
zero through three. If bit five is set, the error conditions listed in
Table 3-9 apply to bits zero through three. If bit five is cleared,
the data conditions listed in the table apply.
To output the status byte in binary form (Figure 3-7) enter the fol-
lowing program into the HP-85
PROGRAM
COMMENTS
IO REMOTE 717 (END Programs the Model 705 into
LINE) the remote mode.
20 S = SPOLL (717) (END
Start serial poll sequence.
LINE)
30 DISPL "B7 86 B5 84 83
Display contents of quotation
82 Bl 80" (END LINE) marks.
40 FOR I=7 TO 0 STEP -1
Loop eight times.
50 DISP
BIT (S,I);
Display status byte.
60
NEXT I
70
DISP
80 END
Press the RUN key to start the program. After the RUN key is
pressed the Model 705 outputs the status byte to the controller.
The controller then displays the status byte in the form shown in
Figure 3-7.
Figure 3-7. Status Byte Format Figure 3-7. Status Byte Format
3.7 STATUS WORD (UO)
The status word commands allow access to information concern-
ing various operating modes of the Model 705. The status word
also contains information about the present status of the input
and output lines on the digital I/O port. When the correct com-
mand is given, the Model 705 outputs the status word or I/O sta-
tus the next time it is addressed to talk instead of sending its
normal data string. Each byte in the status word is a number cor-
responding the previously programmed parameter with the fol-
lowing sequence:
705ADEJKPTGMY
3-23