Teledyne GFC-7000T - Trace CO2 Analyzer - addendum - Manual (Page 12)

Model GFC7000T Carbon Dioxide Analyzer
Teledyne Analytical Instruments 6
EXAMPLE: If the application is to measure between 0 ppm and 50 ppm, an
appropriate Span Gas would be 40 ppm. If the application is to measure between
0 ppm and 100 ppm, an appropriate Span Gas would be 80 ppm.
Zero Air is similar in chemical composition to the earths atmosphere but scrubbed of
all components that might affect the analyzer’s readings. In the case of CO
2
measurements this means CO
2
less than 0.1 ppm of CO
2
and Water Vapor.
Zero Air can be purchased in pressurized canisters or created using a Teledyne
Instruments Model 701 Zero Air Generator in combination with a canister of
indicating soda-lime.
4. Attach an exhaust line to the exhaust outlet port.
The exhaust from the analyzer and vent lines should be vented to atmospheric
pressure using maximum of 10 meters of 1/4” PTFE tubing.
5. Attach a source of dried air scrubbed of CO
2
to the purge inlet port
The source of purge gas should be at least 10 psig and capable of maintaining a flow
of at least 1 liter/min.
Purge source gas pressure should not exceed 30 psig. The purge exhaust is only
used on the GFC 7000TU model.
6. Once the appropriate pneumatic connections have been made, check all pneumatic
fittings for leaks.
5. RELAY ALARM OUTPUTS (STANDARD
CONFIGURATION)
There are 4 relay alarm outputs (AL1-AL4) on the rear panel.
 AL1 is for system okay,
 AL2 is for concentration limit 1 exceeded and
 AL3 is for concentration limit 2 exceeded.
 AL4 is not used
The relay alarm output AL1 is enabled all the time, whereas the AL2 and AL3 can be
enabled/disabled by going into the diagnostics menu (with 929 password), then factory
options, then turning conc. Alarm Relays ON or OFF.
When the concentration alarm relays are enabled, concentration alarms status is no longer
available through the “Status output” pins. So, either the alarm relays or the status bits could
be used to monitor the concentration alarms but not both at the same time. The default
factory setting is to enable the concentration alarm relays.
The AL1 relay is energized when the system is okay and de-energized when the system has
a fault. The AL2 and AL3 relays energize when the corresponding concentration limits are
exceeded.