Keithley 705 Instruction Manual page 39

3. GTL (Go To Local)-The GTL command is used to remove
the instrument from the remote mode.
NOTE
The GTL command does not restore operation of
locked out Model 705 front panel controls, With
some instruments however, local control opera-
tion may be restored by the GTL command. To
restore front panel control operation of the Model
705, the controller must set the REN line false.
Programming Example-If the instrument is not in the
remote and lockout modes, enter the following statements into
the HP-85:
REMOTE 717 (END LINE)
LOCAL LOCKOUT 7 (END LINE)
Check to see that the REMOTE indicator is on and the front
panel controls are locked out. The GTL command sequence is
automatically sent by the HP-85 with the following statement:
LOCAL 717 (END LINE)
Note that the REMOTE indicator on the front panel turns off,
but the front panel controls are still locked out. Front panel
control can be restored by setting the REN line false with the
following statement:
LOCAL 7 (END LINE)
After executing this statement, the front panel controls will
again operate. Setting REN false with the LOCAL 7 statement
will also take the instrument out of the remote mode.
3.5 DEVICE-DEPENDENT COMMANDS
The device-dependent commands allow the user to send the
Model 705 commands that perform the same operations as the
front panel controls switches except for power ON/OFF. There
are a number of commands that control parameters which are
not available from the front panel. Each command is entered as
an ASCII character followed by a specific parameter that is
then sent over the bus by the controller. The bus treats these
commands as data in that the ATN line is high (false) when the
commands are transmitted.
Several commands may be grouped together. Before a com-
mand or command string is executed, the ASCII character X
must be sent. Commands sent without an X (execute) are re-
tained within the Model 705 command buffer until the execute
character is received.
The condition of the status word within the Model 705 is af-
fected by the device-dependent commands. The status word
may be obtained from the unit by using commands covered in
this section. Refer to paragraph 3.7 for status word informa-
tion. Illegal commands do not change the mode of the Model
705 but the status byte condition changes as described in
paragraph 3.6. Normal Model 705 commands are covered in
the following paragraphs, All the device-dependent commands
for the Model 705 are listed in Table 3-7.
The Model 705 executes the programed commands in the
order listed in Table 3-8. This means that if a statement is
entered into the HP-85 as follows:
OUTPUT 717; "PI W3.5 DIX" (END LINE)
The Model 705 executes the commands in the following order
(according to Table 3-8):
1. Displays interval time (Dl).
2. Select single scan mode (PI).
3. Programs interval time for 3.5 seconds (W3.5).
There are three types of commands that make up the device-
dependent commands in Table 3-8.
1. Independent Commands-Commands that do not interact
with each other.
2. Timer Commands-Commands that control the date and
time.
3. Channel Commands-Commands that directly affect the
channels.
3.5.1 Display Mode
The following four commands set the display mode for the
channel, time, date or interval mode.
1. DO-The DO command sets the Model 705 for the channel
display mode.
2. Dl -The Dl command sets the Model 705 for the interval
time display mode. The interval time is the programmed
time the channel is closed. The interval time can be altered
by programming inputs, refer to section 3.5.8.
3. D2-The D2 command sets the Model 705 for the time
display mode. The time in hours, minutes and seconds is
displayed on the front panel, refer to paragraph 2.5.1 step 6
for time display format.
4. D3-The D3 command sets the Model 705 for the date
display mode. The date in month and day is displayed on the
front panel, refer to paragraph 2.5.1 step 6 for date display
format.
5. D4-The D4 command sets the Model 705 for the display
message mode. The display message mode allows the user
to display a customized message on the Model 705's front
panel display.
Programming Example-To transmit the channel data with
a prefix and display the data on the HP-85's CRT enter the
following program into the HP-85:
PROGRAM
COMMENTS
IO REMOTE 717 (END
LINE)
20 CLEAR 7 (END LINE)
30 OUTPUT 717; "GOX"
(END LINE)
40 ENTER 717;AS (END LINE)
50 DISP A$ (END LINE)
60 END (END LINE)
Sets the Model 705 for the
remote mode.
Clear the Model 705.
Send channel data with
prefix.
Obtain data string.
Display data string.
End of program.
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