Measurement Computing Daq PC-Card - Manual (Page 36)

DaqBook/100, /112, /120, /200, /216 Daq* Hardware
3-6 10-18-00 DaqBook/DaqBoard/Daq PC-Card User’s Manual
Time Base Selection (JP5)
JP5 is a 2×3 header that allows you to apply 1 of 3 oscillator-
derived frequencies to the 8254 timer chip. The frequencies are
100 kHz, 1 MHz, and 10 MHz. The default setting is 1 MHz.
Note: A special-version 8254 timer-chip is required for 10 MHz.
DaqView and most 3rd party software assume the 1 MHz
time base.
JP5 Time Base Settings
Watchdog Timer Enable/Disable (JP6)
This 3-pin header (JP6) allows the elective use of the watchdog timer. The
watchdog timer is used to assure consistent operation of the pass-through printer
port during data collection and to restore pass-through printing if the computer is
reset. Enable the watchdog timer if you:
•
Use a printer on the pass-through printer port
•
Expect the computer to be suddenly reset during DaqBook operation
•
Want the DaqBook to reset itself rather than having to manually toggle the
DaqBook’s power switch.
Place the shunt jumper in the desired position as shown in the figure. The default
setting is Disabled.
Note: The watchdog timer can mistake a computer pause for a reset and then impede background
measurements. For this reason, the watchdog timer should normally be disabled unless automatic
restoration of pass-through printing is required.
Connections
The DaqBook connects to the computer’s parallel printer port (female DB25) with the supplied cable (CA-
35-2). Connect the male end to the computer and the female end to the DaqBook connector labeled FROM
PC PARALLEL PORT. Any printer port (LPT1, LPT2, or LPT3) may be used but should be noted for
software setup. When using a printer, attach the original printer cable (male DB25) into the DaqBook
connector labeled TO PARALLEL PRINTER.
Note: Printing cannot occur during data acquisition.
The DaqBook may be powered with a supplied AC adapter that plugs into any standard AC wall outlet. An
isolated VDC source of 1-2 amps may also be used. Power requirements are +7-20 VDC for the
DaqBook/100/112/120, +10-24 VDC for the DaqBook/216, and +9-18 VDC for the DaqBook/200/260.
Before plugging unit in, make sure the power switch is in the “0” (OFF) position.
•
If using an AC power adapter, plug it into an AC outlet and attach the low voltage end to the jack on
the DaqBook.
•
If using another VDC source, make sure leads are connected to the proper DIN terminals.
JP6 Watchdog Timer
Settings