Metrohm 791 VA Detector - Manual (Page 45)

4.4 Instrument test with the dummy cell
791 VA Detector
39
11 Set commutator 3 "meas" to "on" position
(depressed position).
meas
12 Unplug dummy cell at "AE": the overload
display 2 lights up.
4.4.5 Check sensitivity knob 8
1 Unplug dummy cell.
2 Set adjusting knob 8 to 50 nA.
4
5
1
10
50
1
5
0,1
0,5 100
10
0,5
0,1
3 Set commutators 3 … 7 to "off" position (non-
depressed position).
4 Set potentiometer 9 I
comp
abs. to 0.
0.02 nA
Icomp
5 Set selector 21 on the rear panel to 0 … 1 V.
0...10 mV
0...1 V
6 Bring recorder of voltmeter to 0 using potenti-
ometer 10 I
comp
rel. (set line recorder first to mid-
scale).
Icomp
. I 0.01
7 Turn adjusting knob 8 through all positions and
check the deviation from zero after a waiting
time of app. 5 s. Deviation should be < ± 1 V.
4
5
1
10
50
1
5
0,1
0,5 100
10
0,5
0,1