Metrohm 797 VA Computrace Manual de usuario descargar pdf (Pagina 59)

3.2 VA measurement modes

797 VA Computrace – Software

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.

Base potential (V) [ -5...+5 V ; -0.9 V ]

Base voltage for voltage sweep.

Pulse time (s) [ ≥ 500 μs ; 0.04 s ]

Time interval during which an increasing voltage pulse is su-

perimposed on the base 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 ]

Ramp slope calculated as Voltage step / Voltage step time.

Notes:

• The NP measurement mode can be used with all types of elec-

trodes (but only in the exploratory mode!).

• 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 + 220 ms (DME)

Voltage step time > Pulse time + Drop size × 40 ms + 200 ms

(SMDE)

• The measurement time t (i) is defined as follows:

Pulse time ≥ 40 ms → t (i) = 20/16.67 ms (power frequency

50/60 Hz)

Pulse time < 40 ms → t (i) = 0.5 × Pulse time

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Metrohm 797 VA Computrace Manual de usuario Pagina 59