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Electronic Copy of LTI’s Impulse User’s Manual 8
th
Edition © October 1998
Discarding Error Messages
When using the automatic download mode, you
can choose whether to download every
measurement, with or without null data from error
conditions, or to download valid measurements
only.
Set this preference by scrolling to the SYS-Err
option and press Fire to toggle the feature on, to
download both measurement values and null data,
or off, to download valid measurements only.
Optional Remote Trigger
It is possible to remotely trigger the Impulse and
take a measurement by using an external
computer, data collector, or switch closure. Remote
triggering is accomplished by providing an open
collector closure to ground or an active low TTL or
RS232 level
signal to the ‘trigger’ pin on the serial connector.
This option requires a special order download cable
that connects the remote trigger signal from the
Impulse to the ‘RTS’ output signal of a computer’s
serial port.
When using a serial cable with a remote trigger
connection, care must be taken in controlling the
state of the RTS signal from the host computer.
Often times the default
state of the RTS signal will be low, causing
an inadvertent trigger of the Impulse. Since the
remote trigger signal is treated the same as a
keypress on the Impulse keypad, holding the signal
low is identical to holding down a function key,
which prevents a response to any additional keys
that are pressed.
