Metrohm 757 VA Computrace User Manual
Page 42
3 General settings for exploratory and determination mode
757 VA Computrace – Software
32
Sweep parameters:
Hydrodynamic (measurement) [ on, off ; off ]
Enable/disable stirring of the RDE/SSE during the sweep.
Start potential (V)
[ -5...+5 V ; -0.9 V ]
Start voltage for the voltage sweep.
End potential (V)
[ -5...+5 V ; -0.1 V ]
Final voltage for the voltage sweep.
Pulse amplitude (V)
[ -1...+1 V ; 0.05 V ]
Pulse amplitude of the voltage pulse superimposed on the
direct voltage (pos. values = same direction; neg. values =
reversed direction with respect to the scan direction).
Pulse time (s)
[ > 500 µs ; 0.04 s ]
Time interval during which a voltage pulse is superimposed
on the direct voltage.
Voltage step (V)
[ > 0 V ; 0.006 V ]
Voltage step for direct voltage ramp.
Voltage step time (s)
[ > 0 s ; 0.4 s ]
Time interval after which the voltage in the sweep is in-
creased or decreased by the amount
Voltage step
.
Sweep rate (V/s)
[ read only ]
Display of the ramp slope calculated as
Voltage step / Voltage
step time
.
Notes:
• The DP measurement mode can be used with all types of
electrodes.
• The following conditions apply to the definition of the
Voltage
step time
:
Voltage step time > Pulse time + 10 ms
(HMDE/RDE)
Voltage step time > Pulse time + 30 ms
(DME)
Voltage step time > Pulse time + Drop size × 40 ms + 10 ms
(SMDE)
• The measurement time
t (i)
is defined as follows:
Pulse time ≥ 40 ms
→
t (i) = 20/16.67 ms
(50/60 Hz)
Pulse time < 40 ms
→
t (i) = 0.5 × Pulse time