Teledyne T200, Operation Manual, Page: 84 / 425

Setup Mode Menus Teledyne API
– T200 NO/NO
2
/NO
X
Analyzer Operation Manual
82
5.2. SETUP

ACAL: AUTOMATIC CALIBRATION OPTION
The menu button for this option appears only when the instrument has the zero span
and/or IZS options. Section 9.5 provides details.
5.3. SETUP

DAS: INTERNAL DATA ACQUISITION SYSTEM
Use the SETUP>DAS menu to capture and record data. Section 7 provides configuration
and operation details.
5.4. SETUP

RNGE: ANALOG OUTPUT REPORTING RANGE
CONFIGURATION
Use the SETUP>RNGE menu to configure output reporting ranges, including scaled
reporting ranges to handle data resolution challenges. This section describes
configuration for Single, Dual, and Auto Range modes.
5.4.1. T200 PHYSICAL RANGES
The T200 measures NO
x
, NO and NO
2
concentrations from 2 to 20,000 ppb.
Electronically the T200 analyzer converts the 0-5 volt analog signal output by the PMT
to a digital signal with 4096 counts of resolution. Since its measurement range is 0 ppb
to 20,000 ppb, this only allows about 3 ppb per count. While this might be acceptable
for high concentration measurements made in parts per million units (ppm), it is not
good enough for lower level NO
x
measurements. To overcome this limitation the T200
is designed with two physical measurement ranges:

LOW
range to measure concentration from 0 ppb to 2,000 ppb with a resolution of
0.27 ppb per count

HIGH
range to measure the full 20,000 ppb range of the analyzer
The analyzer‟s CPU chooses the appropriate range based on how the user sets up the
reporting ranges for the instrument‟s analog outputs: when an analog range is selected
with a lower limit between 0 and 2000 ppb, the analyzer will utilize its
low physical
range. When an analog range is in use that has a reporting range with an upper limit set
between 2001 and 20,000 ppb, the instrument will operate in its high physical range.
Once both ranges have been using the same span gas values, the analyzer‟s front panel
will accurately report concentrations between 0 and 20,000 ppb, seamlessly switching
between the low and high physical ranges regardless of the selected analog reporting
range.
5.4.2. T200 ANALOG OUTPUT REPORTING RANGES
For applications using chart recorders or other analog recording devices, the T200's
20,000 ppb physical range can cause resolution problems. For example, in an
application where the expected concentrations of NO, NO
2
and NO
x
are typically less
than 500 ppb, the full scale of expected values is only 2.5% of the instrument‟s
20,000 ppb physical range. The corresponding output signal would then only be
recorded across 2.5% of the range of the recording device.
06858E DCN7057