Metrohm 797 VA Computrace - Manual (Page 61)

3.2 VA measurement modes
797 VA Computrace – Software
49
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.
First vertex potential (V) [ -5...+5 V ; -0.1 V ]
First turning point for the potential sweep.
Second vertex potential (V) [ -5...+5 V ; -0.9 V ]
Second turning point for the potential sweep (Can be differ-
ent from the
Start potential ).
Voltage step (V) [ > 0 V ; 0.006 V ]
Voltage step for direct voltage ramp.
Sweep rate (V/s) [ > 0 V/s ; 0.1 V/s ]
Ramp slope = Voltage step / Voltage step time .
No. of sweeps [ > 0 ; 1 ]
Number of cyclic sweeps to be performed.
Save last ... sweeps]
Number of cycles to be saved.
Note: Total number of saved sweeps is number of
Save last
sweeps multiplied with No. of replications .
Notes:
• The CV measurement mode can only be used with HMDE or
RDE electrodes.
• The following condition applies to the definition of
Voltage
step and Sweep rate :
Voltage step time = Voltage step / Sweep rate > 270 μs
• The measurement time t (i) is defined as follows:
Voltage step time ≥ 80 ms → t (i) = 20/16.67 ms (power fre-
quency 50/60 Hz)
Voltage step time < 80 ms → t (i) = Voltage step time / 4 (Volt-
age step time = Voltage step / Sweep rate)