Buchi C-640, Operation Manual

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3 Technical data
15
C-640 Operation Manual, Version C
3 .4 Configuration of the analog cinch output
a
Analog Output (HI)
Absorbance signal output. Voltage magnitude cor-
responds to the actual absorbance in the cell. The
conversion factor depends on the settings. Output
range is from -0.2 V to 1.2 V. The analog output is
single ended.
b
GNA (Low)
Analog ground of the output signal. The analog
ground is connected to the instrument housing.
Figure 3-1: Configuration of the cinch outputs (female)
3 .5 Light sources
3 .5 .1 Deuterium lamp
The primary light source of the detector C-640 is a deuterium lamp with an average lifespan of about
1000 operating hours.
A lamp test can be performed across the whole range of the detectable spectrum (Scan) or on the
four selected wavelengths of the detection channels (A–D) only.
Note
Aging of the deuterium lamp is correlated to the measured wavelengths, e.g. if the lamp is mainly
used in the range of 200 to 250 nm, the lifespan will be reduced.
To perform the test, assemble the black test cell to the cell compartment and measure the light inten-
sity. The result can be interpreted according to the following table:
Measured light intensity Meaning Solution
> 50% Lamp is in good condition. No replacement of the lamp required.
> 10% but < 50% Lamp is working, but noise and drift of the
system may be higher. Starting the lamp
might get more and more problematic. The lamp may be replaced to minimize
noise and drift. As soon as starting prob-
lems with the lamp occur, a replacement
of the lamp becomes necessary.
< 10% Lamp is at the end of its lifespan. The lamp needs to be replaced. (See
chapter 6.4 “Replacement of the deute-
rium lamp”.)
3 .5 .2 Halogen lamp
The secondary light source of the instrument is a halogen lamp. This lamp is always used together
with the deuterium lamp. Even if this lamp has a very big lifespan, a replacement of this lamp may
become necessary. A check for any damages is carried out during each initialization of the halogen
lamp. The replacement of the halogen lamp can only be performed by a specialist. Please contact
your local service.