ELTRA ONH-2000 - Page 47

 2002 by ELTRA GmbH Germany – January 2002 – Service Manual OH 900 / ON 900 / ONH 2000
2.3-2
In case the drift is too large:
 Check the temperature regulation, see 2. 5
 Unstable power supply, see 2. 4
 Defective IR source, see 3. 2
 By pressing the < CLR > key, you can end the test.
 Notice :
In case of a serious defect, if the output voltage of the infrared cell is more than
10 volts, ++++ is shown on the display.
Adjusting the infrared cell
The connection sockets of the measurement channels ( 10 / 11 ) are predetermined on
the circuit board IR 21.
The position of the IR paths on the path plate ( 22 ) is open, and can be changed
according to the layout of the measuring ranges.
10 Connection for O-channel
11 Connection for low O-channel
13 / 14 Pre-amplifiers for O and low channel
16 / 17 Adjusters for pre amplifiers
19 / 20 / 21 Zero fine adjustment for baselines.
 Each channel is adjusted separately.
 Set the trimmers ( 19 / 20 / 21 ) in the middle of their range.
 Connect a digital voltmeter on the outlet 6 and the ground 7
( measuring range 200 V DC )
 Adjust 0 volts DC by adjusting the preamplifiers ( 16 / 17 )
2
3
4
5
2
3
4
5
2
3
4
5
2
3
4
5
11
CO M V DC
6 7
GN D GN D
06005
ELTRA-IR21
1011
1
6
1
7 7
GN D
VAC
G ND
13
16
14
17
22
20 1921
O UT OUT
OUT
6
sw
ge
rt
2-3