12 | Model ta5000F Gas Purity Monitor
bustion into H
2
O and CO
2
. The resultant electrons are collected to gener-
ate a current signal. Higher hydrocarbons, those containing more than a
single carbon group, generate additional CH
+
Ions in proportion to the
carbon number. As a result the theoretical sensitivity of the flame ioniza-
tion detector to non-methane hydrocarbons is at least two times higher
than methane.
Contamination of carrier gases with reactive compounds such as sulfides,
chlorides, and aromatics will irreversibly impair reactivity and will neces-
sitate methanizer replacement. Care should be taken to bypass the instru-
ment if these compounds are present in the sample gas stream.
Operating System
A six-button keypad enters commands to the microprocessor, which moni-
tors detector operation, controls heated zones, and operates all internal
valve functions. External signal outputs for a data collection system or
host computer are located at the rear panel.
The microprocessor control system allows complete unattended operation
of the ta5000F. This onboard system performs necessary operational and
analytical functions such as:
• Analyzer
Status
Control
• Contaminant
Identification
• Concentration
Calculations
• Calibration
• Sampling
Frequency
• Data
Output
• Alarm
Output
Data is presented via the front display panel. Alternatively data may be
obtained through an RS232 serial computer interface and HP parallel
printer interface located on the rear panel.
With optional interface kits, two components may be assigned to separate
trend channels to provide a continuous signal proportional to the con-
centration of the assigned component. These trend signals are updated
following each run and can be tracked by a data logger or host computer.
