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Teledyne 7300a - NDIR analyzer User Manual

Page 48

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4 Operation

Model 7300A

4-12

Teledyne Analytical Instruments

Hard_offset_C=3015 (This is the raw DAC count of the Coarse zero

adjustment. It should read between 0 and 4095)

Hard_offset_F=2715 (This is the raw DAC count of the Fine zero

adjustment. It should read between 0 and 4095)

Current_gain = 4

(This is the gain the analyzer is on, it should read

between 0 and 9)

4.3.9 Digital Filter Setup

The 7300A analyzer has the option of decreasing or increasing the

amount of filtering on the signal. This feature enhances the basic filtering done by
the analog circuits by setting the amount of digital filtering effected by the micro-
processor. To access the digital filter setup, scroll through the menu and select
FILTER. Press the Enter key to see the following screen:

Enter Digital

Filter: 4

The number on the second row can be adjusted from 0, minimum digital

filtering, to 10, maximum digital filtering. The default setting is 4 and that should
suffice for most applications. In some applications where speeding the response
time with some trade off in noise is of value, the operator could decrease the
number of the digital filter. In applications where the signal is noisy, the operator
could switch to a higher number; the response time is slowed down though.

10 to 90% response time on the different settings to a step input is

shown below. This response time does not include the contributions of the bench
sampling system and the preamplifier near the detector.

Setting

10-90% Response

(seconds)

0

2.5

1

5

2

10

3

20

4

40

5

80