Owner manual

5.7.3 Alphabetical instruction list

746 VA Trace Analyzer / 747 VA Stand

5-225

DME Page: O, S Stand: M, A Abbreviation: DM

Instructions t/s Main parameters Auxiliary parameters

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## .. DME .....

Function Switch on Dropping Mercury Electrode (DME).

Description The DME instruction is used to switch on the 6.1246.020 Multi-Mode

Electrode as a dropping mercury electrode, the mercury starts to flow out

freely. In a subsequent voltage sweep, the Hg drops are knocked off by

a tapping mechanism after the time t.step set in the measurement

mode.

t.step

F (Hg)

The set drop time t.drop important for certain parameter settings is

20 ms for the DME.

Comments • Within a program, the DME is not switched off until the ØMEAS

instruction or the selection of a different electrode type (HMDE, SMDE or

RDE). The DME is also switched off by END in the main program on

the "OP.SEQUENCE" page, but not by END in the segment.

• The DME can be used for the following measurement modes and

sweeps: DCTMODE with SWEEP and SSWEEP,

DPMODE with SWEEP and FSWEEP,

SQWMODE with SWEEP and FSWEEP,

AC1MODE with SWEEP,

AC2MODE with SWEEP.

• The following are not compatible with the DME:

CYCMODE with (CSWEEP,

PSAMODE with PSWEEP as well as

TSWEEP.

• An advantage of the DME compared with the SMDE is that the MME

capillary is subjected to less mechanical stress.

• A disadvantage of the DME compared with the SMDE and HMDE is

the higher mercury consumption and the lower sensitivity as the

electrode surface and hence the baseline constantly changes during

the measurement phase.