User`s guide

4-13
Operation 4
Delay Volume
When the selected gradient profile is a solvent
composition (%B for instance), the Delay Volume
can be used to synchronise on the recorder the plot
of the programmed profile with the plot of the
detected profile (baseline drift). In this case the
delay volume is generally defined, for a first ap-
proximation, as being the total volume between the
mixer inlet and the detection cell inlet. The value is
adjusted from experimental observation to obtain
the desired synchronisation.
The 305 software divides the Delay Volume by the
total flow rate to calculate the total delay time
applied to the analog output Gradient Profile. The
size of the Delay Volume can be specified between
0.01 mL and 999 mL.
# The default value is 0, i.e. no delay volume specified.
• Key in the required delay volume and press Enter.
Zero Manometric Module
The Zero soft key is used to set the manometric
module value to zero when there is zero pressure in
the system. This ensures accurate pressure readings
when the pumps are running. Before pressing the
Zero soft key, make sure that all pumps have stopped
and that the pressure has dropped to zero. Other-
wise further pressure indications will be incorrect.
This can be easily done by opening the prime/purge
valve whilst the pumps are not operating. If the
operation is successful the message Pressure read-
ing is zero is displayed. If the operation is not
successful, the message Not done - check pressure
readings is displayed.
You have now completed the Input/Output pa-
rameter setup. Press Quit to leave this branch of
the software. This will bring you back to one of the
Ready-to-Run screens.
Summary:
• Press the Menu soft key.
• Press the I/O soft key.
• Set the High Pressure Limit (Maximum value
depends on Manometric Module).
• Set the Low Pressure Limit.
• Set the Alarm to be On or Off.
Setting Up the Pump
The Delay Volume option will
only appear if %B or %C has
been selected for Gradient
Profile.