Signal Output
Test signal output
To access this function, the following key sequence is entered:
SIG 1 | (or | SIG 2 | ) | 9 | ENTER |
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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. |
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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:
CSetpoint values assigned to 
RANGE 2!( ) 
and 
ATTN 2!( ) 
affect level of the test signal output, as do equivalent functions on the receiving
device.
CAn 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.
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