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58 211_0010 - ROXY Exceed user manual - rev 04
Range
Range selection is done in the ‘SETUP’ or ‘STAT’ screen in DC, PULSE
and SCAN mode. A number of ranges can be selected; the maximum cur-
rent that can be compensated for using auto zero and offset differs. The
high sensitivity ranges (1 nA - 10 nA) have the best noise specifications. In
fact, there is a trade-off between best noise specification at sensitive
ranges, and maximum compensation at the less sensitive ranges. This is
an inevitable consequence of the tremendous dynamic range that is cov-
ered by the potentiostat.
Table II. DC ranges and maximum compensation.
Range FS Max comp Range FS Max comp
100 mA
(1)
250 mA
(2)
5 µA 25 µA
50 mA 250 mA 2 µA 25 µA
20 mA 250 mA 1 µA 25 µA
10 mA 25 mA 500 nA 25 µA
5 mA 25 mA 200 nA 25 µA
2 mA 25 mA 100 nA 250 nA
1 mA 2.5 mA 50 nA 250 nA
500 µA 2.5 mA 20 nA 250 nA
200 µA 2.5 mA 10 nA 25 nA
100 µA 2.5 mA 5 nA 25 nA
50 µA 2.5 mA 2 nA 25 nA
20 µA 2.5 mA 1 nA 25 nA
10 µA 25 µA
In the PULSE and SCAN mode the current is much higher than in DC
mode. Therefore it is not possible to select ranges below 200 nA. See Ta-
ble III on the next page.
(1) Although a range can be selected of 100 mA, the actual maximum
current which can be measured by the potentiostat is 35
– 50 mA
depending on the measurement conditions.
(2) 250 mA is the theoretical maximum compensation which can be
applied in these ranges, the practical maximum compensation is limited
by the maximum current which can be measured by the potentiostat
(see point 1).