Trigger Modes - Keithley 705 Instruction Manual

3.5.6 Trigger Modes
Triggering is used to tell the Model 705 to initiate the program
mode sequence (single, continuous or step). The trigger stimulus
may come from commands sent over the bus through the exter-
nal input or by the front panel START/STOP button. Triggering
may be to either start the program mode sequence or stop the
program mode sequence. The trigger modes are as follows:
1.
2.
3.
4.
5.
6.
7.
8.
TO - In the TO mode a Talk command initiates the program
mode sequence.
Tl - In the Tl mode a Talk command stops the program
mode sequence.
T2 - In the T2 mode a GET command initiates the program
mode sequence.
T3 - In the T3 mode a GET command stops the program
mode sequence.
T4 - In the T4 mode an execute command "X" initiates the
program mode sequence.
T5 - In the T5 mode an execute command "X" stops the
program mode sequence.
T6 - In the T6 mode an external trigger initiates the pro-
gram mode sequence.
T7 - In the T7 mode an external trigger stops the program
mode sequence.
Programming Example
- Set the instrument to its default
condition by turning the unit off then on and enter the following
statements into the HP-85 keyboard:
REMOTE 717 (END LINE)
OUTPUT 717; "T2X" (END LINE)
After the END LINE key is pressed the second time, the instru-
ment is placed in the start on GET trigger mode. When a GET
command is sent by the controller the Model 705 triggers. To
send a GET type the following into the HP-85.
TRIGGER 717 (END LINE)
Trigger
ModeTO - If the Model 705 is in trigger mode TO (Start
on Talk), either of the following HP-85 BASIC statements will
initiate a scan:
SEND 7; TALK 17
S=SPOLL (717)
Requesting data from the Model 705 will stop the scan. The
statement:
ENTER 717; A$
does not initiate a scan since the controller addresses the
Model 705 to talk and then requests data in the same statement.
3.5.7 ProgrammableTerminator (Y)
The Model 705 uses special terminator characters to mark the
end of its data string. To allow a wide variety of controllers to be
used, the terminator can be changed by sending the appropriate
command over the bus. The power-up default value is the com-
monly used carriage return, line feed (CR LF) sequence. The ter-
minator assumes this default value upon power-up or after the
instrument receives a DCL (Device Clear) or SDC (Selected
Device Clear).
The terminator may be programmed by sending the ASCII char-
acter Y followed by the desired terminator character. Any ASCII
character except one of the following may be used:
1. All capital letters
2. All numbers
3. Blank
4. +
5. -
6. I
7. 9
8.
9. e
IO. :
Special command characters will program the instrument for
special terminator sequences as follows:
1. Y(LF) = CR LF (Two terminators)
2. Y(CR) = LF CR (Two terminators)
3. Y(DEL) = No terminator.
NOTE
Most controllers use the CR or LF character to ter-
minate their input sequences. Using a nonstandard
terminator may cause the controller to hang up
unless special programming is used.
Programming Example
- Enter the following statements into
the HP-85 keyboard:
REMOTE 717 (END LINE)
OUTPUT 717; "YtX" (END LINE)
ENTER 717; t$ (END LINE)
After END LINE is pressed the first time the Model 705 is placed
in the remote mode. After END LINE is pressed the second time
the terminator is changed to the ASCII character T. After END
LINE is pressed the third time, the HP-85 ceases to operator
because it is waiting for the standard terminator sequence. The
HP-85 may be reset by holding down the SHIFT key and then
pressing RESET on the keyboard.
3.5.8 inputs
NOTE
Refer to paragraph 2.6.7 for more details on using
Program 6, including recommendations on mixing
card types.
CAUTION
When a Model 705 mainframe contains a mix
of cards (matrix, lo-channel, 20-channel),
you can use more than one pole mode to
address the cards. In other words, use the
O-pole mode for a matrix card, the l-pole
mode for a 20-channel card, and the a-pole
mode for a 1 O-channel card. In cases where a
O-pole mode card is used with a 10 or
20-channel card, you must place the
Model 705 into the O-pole mode before using
the l-pole or P-pole mode. This action will
properly initialize the O-pole mode card. Then
you can place the Model 705 into the l-pole
or a-pole mode to address the other card.
This operation is not necessary if the main-
frame powers up in the O-pole mode.
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