WATERS CORPORATION 2424, Operator'S Manual, Page: 89 / 196

Setting up a run 3-25
Setting the switch output
The detector has a general purpose switch output that can be controlled
manually, by run time, or by sample level. On the third Home screen, it
displays the current setting of the method and the switch output. Changing
the initial value, On or Off, also changes the current state of the switch
output.
For information on programming the switch output by time or by level, see
page 3-37 .
Setting the analog signal output
The fourth Home screen contains the sample signal analog output
parameters, the units full scale value, the analog output full-scale value, and
its offset. These settings only affect the sample signal’s analog output, not the
digital data processed by the data system using the Ethernet communications
data link.
The units full scale value defines the maximum signal value that can be
represented using the analog output. Likewise, the analog output full-scale
value defines the maximum output voltage value that will be used to
represent the units full-scale value. For example, using the default values, the
units full-scale value of 2000 is represented as a 2000-mV output on the
analog outputs. Reducing the units full-scale value to 1000 means that the
2000-mV analog output will represent a 1000-LSU signal. This also increases
the analog output sensitivity from 1 LSU/mV to 0.5 LSU/mV.
Changing the analog output full-scale value reduces the sensitivity of the
analog output. For example, changing the analog output full-scale value to
1000 mV reduces the analog output sensitivity from 1 LSU/mV to 2 LSU/mV.
The analog output sensitivity can be improved by also reducing the units
full-scale value to 1000 LSU to obtain a 1 LSU/mV sensitivity.
The offset data field provides a way to raise the analog output signal to meet
the detection signal requirements of some data loggers.
Setting auto zero options
The fifth Home screen contains options for setting various auto zero options,
either when the gain is changed or at the start of a run (on inject).