Metrohm 746 VA Trace Analyzer - Manual (Page 443)

5.7 Program instructions
746 VA Trace Analyzer / 747 VA Stand
5-292
SQWMODE Page: O, S Stand: M, A Abbreviation: SQ
Instructions t/s Main parameters Auxiliary parameters
––––––––––––– ––––– ––––––––––––––––––––––––– –––––––––––––––––––––––––
## .. SQWMODE ..... U.ampl ........mV Modul.freq. ........Hz
t.step ........s Prep.cycles ........
t.meas ........ms Meas.cycles ........
Function Measurement mode for square wave voltammetry.
Application Square wave voltammetry with the SQWMODE measurement mode is
primarily suitable for reversible electrode processes. It is used particu-
larly for sensitive stripping voltammetric determinations at the HMDE or
RDE.
Parameter Range; Default value / Meaning
U.ampl 1...50 mV; 20 mV
Voltage amplitude
Voltage amplitude of the superimposed square wave voltage.
t.step 0.05...9.9 s; 0.3 s
Time interval for voltage step
Time interval after which the voltage in the sweep is increased or
decreased by the amount
U.step .
The following condition applies to the definition of t.step :
Meas.cyc. + Prep.cyc.
t.step > ––––––––––––––––––––– + t.drop + 30 ms
Modul.freq.
t.meas 0.1...32.0 ms; 2.0/1.66 ms for 50/60 Hz
Measurement time
Time during which the current is measured. Measurement is performed
at the end of the time interval
t.step immediately before the pulse
start and at the end of the pulse.
The following condition applies to the definition of t.meas :
0.5 32 ms
––––––––––– – 1 ms > t.meas < –––––––––––
Modul.freq. Meas.cycles
Modul.freq. 10...250 Hz; 50/60 Hz for 50/60 Hz
Modulation frequency
Modulation frequency of the superimposed square wave voltage.
Prep.cycles 0...255; 0
Number of preparation cycles
Number of square wave voltage cycles without current measurement
which are performed for every voltage step before the measurement
cycles.