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Varian ELSD Service Manual
OVERVIEW OF DETECTOR’S OPERATION MODES
The Varian ELSD can be operated in two modes; STANDBY and RUN as described below:
To display the current mode and/or select a new mode, highlight the
MODE
function on the instrument display. The
current mode will now be displayed on the screen. Using the
▲▼
keys, scroll up or down until the desired option is
displayed. The instrument acknowledges the command by displaying the mode of operation in the top right hand
corner of the screen.
Standby Mode
The STANDBY mode is the “ground state” of the Varian ELSD instrument, which is initiated automatically after power
on. In this mode of operation the heaters are off, and the gas manifold valve is closed. The STANDBY mode
enables the user to set-up the operational parameters (gas flow, nebuliser and evaporator temperatures) before
switching the unit into RUN mode. The instrument will default to STANDBY mode should an error occur on the
instrument
When the instrument is switched from RUN mode to STANDBY mode, following a command or error then the gas
flow is set to a minimum flow of 1.2SLM for 15minutes before the gas manifold valve is closed. This minimum
“blanket” gas is enough to nebuliser and evacuate solvent should the instrument default to STANDBY mode with
solvent still flowing [firmware 1.1.8 or later].
If the Instrument is left in STANDBY mode for longer than 15mintes, gas flow
to the unit is stopped to minimize gas usage.
It is strongly recommend that the pump stop from the I/O connector of the
Varian ELSD is connected to the HPLC pump to prevent solvent flooding of
the detector should an error occur
Run Mode
The RUN mode is the detector’s normal operational mode. In this mode, the instrument controlled at the set
temperatures and gas flow, and the system is fully operational. During heating or cooling the instrument will display
‘NOT READY’ to show the system has not
reached the set conditions. When the instrument has reached the set conditions and equilibrated, ‘READY’ will be
displayed and the instrument is ready for use.
USING THE INSTRUMENT IN ‘NOT READY’ STATUS MAY NOT PRODUCE
CONSISTENT RESULTS ACCORDING TO THE SET PARAMETERS, AS THE
SYSTEM IS NOT EQUILIBRATED.
