Metrohm 797 VA Computrace User Manual
Page 57
3.2 VA measurement modes
797 VA Computrace – Software
45
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.
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 increa-
sed 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 DC measurement mode can be used with all types of elec-
trodes except for DME and SMDE in the determination mode.
• The following conditions apply to the definition of the
Voltage
step time
:
Voltage step time > 270 μs
(HMDE/RDE)
Voltage step time > 220 ms
(DME)
Voltage step time > Drop size × 40 ms + 200 ms
(SMDE)
• The measurement time
t (i)
is defined as follows:
t (i) = 20/16.67 ms
(
power frequency 50/60 Hz
)