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Operation
3-4
3.7
Scanning output channels
Output channels are scanned by creating a scan list and con-
figuring the Model 7001/7002 to perform a scan. The scan
list is created in the same manner as a channel list (see Turn-
ing Output Channels On and Off). However, the scan list is
specified from the “SCAN CHANNELS” display mode. The
SCAN LIST key toggles between the channel list and the
scan list. The following shows an example of a scan list:
SCAN CHANNELS 2!1, 2!3, 2!21-2!25
When a scan is performed, the channels specified in the scan
list will be scanned in the order that they are presented in the
scan list.
Channel patterns can also be used in a scan list. This allows
you control specific bit patterns for logic circuits. Example:
SCAN CHANNELS M1, M2, M3, M4
When M1 is scanned, the channels that make up channel pat-
tern M1 will turn on. When M2 is scanned, the M1 channels
will turn off and the channels that make up M2 will turn on.
M3 and M4 are scanned in a similar manner. Refer to the in-
struction manual for the mainframe for information on defin
ing channel patterns.
A manual scan can be performed by using the RESET de-
fault conditions of the Model 7001/7002. RESET is selected
from the SAVESETUP menu of the main MENU. When RE-
SET is performed, the mainframe is configured for an infinit
number of manual scans. The first press of STEP takes the
mainframe out of the idle state. The next press of STEP will
close the first channel specified in the scan list. Each subse-
quent press of STEP will select the next channel in the scan
list.
3.8
Reading input channels
Input channels are read from the READ-I/O-CARD option
of the CARD CONFIG MENU of the mainframe. This menu
is accessed by pressing the CARD key. In this “read input
channels” display mode, the mainframe displays the real-
time state of each input channel.
Input channels use positive true logic. A channel is on
(closed) when the input is high. Keep in mind that an open
input is pulled high by the internal pull-up resistor. Con-
versely, a channel is off (open) when the input is pulled low
to ground.
Perform the following steps to configure the mainframe to
display the digital input channels:
1. Press the CARD CONFIGURATION key to display the
CARD CONFIG MENU.
2. Use the and keys to place the cursor on READ-I/
O-CARD and press ENTER.
Model 7001 Mainframe — The real-time state (on or
off) of each input channel is provided on the display.
Only I/O card channels are displayed.
Model 7002 Mainframe — The real-time state (on or
off) of each channel is provided by the appropriate LED
display grid. Use the TYPE option of the CARD CON-
FIG MENU if you don't know which slot the I/O card is
installed in.
3. Use the EXIT key to exit from the “read input channels”
display mode.
NOTE
With input channels displayed, you can
turn off (open) all output channels by
pressing OPEN ALL.
3.9
IEEE-488 bus operation
Bus operation is demonstrated using Microsoft QuickBASIC
4.5, the Keithley KPC-488.2 (or Capital Equipment Corpo-
ration) IEEE interface and the HP-style Universal Language
Driver (CECHP). Refer to “QuickBASIC 4.5 Programming”
in the mainframe manual for details on installing the Univer-
sal Language Driver, opening driver files and setting the in-
put terminal. Program statements assume that the primary
address of the mainframe is 07.
3.10 Turning output channels On and Off
The following SCPI commands are used to turn output chan-
nels on and off:
:CLOSe <list>
Turn on specified channel
:OPEN <list>|ALL
Turn off specified (or all) channels.
The following program statement turns on channels 1!1, 1!4
through 1!6, and the channels that make up channel pattern
M1.
PRINT #1, "output 07; clos (@ 1!1, 1!4:1!6, M1)"
Notice that the colon (:) is used to separate the range limits.