Signal Output
Test signal output
78
To access this function, the following key sequence is entered:
SIG 1
(or
SIG 2
)
9
ENTER
Test plot mode is confirmed by the display SIGNAL 1 (or 2) TEST
PLOT. Pressing
SIG 1
(or
SIG 2
) a second time displays the current
signal level value (which is 0.0 initially). This permits monitoring the
output signal.
The chromatogram is initiated by pressing
START
. The chromatogram
continues to cycle until
STOP
is pressed. Each cycle is about 1•1/2
minutes in length.
Note:
Setpoint values assigned to
RANGE 2 ()
and
ATTN 2 ()
affect level of
the test signal output, as do equivalent functions on the receiving
device.
An oven temperature program (e.g., a setpoint value for
RATE
other
than 0) must be set up at the HP 5890 for the test plot to function.
The test chromatogram is useful as a troubleshooting aid in deciding
whether a lost or noisy signal observed at a connected integrating or
chart recording device is due to a chromatographic problem (lost sample
due to leaks, noise due to a dirty detector, etc.), versus problems either
with the integrating/recording device itself, or in its connecting cables.
If the test chromatogram does not exhibit any problems at the
integrating/recording device, a chromatographic problem is likely to exist;
if the test chromatogram exhibits noise, or does not appear at all, the
problem is not likely to be chromatographic.
