User guide

60 Advanced User Guide
3 Options
sensor output, and turns the gas back on. This takes about two
seconds. The zero offset is used to correct future flow
measurements.
To activate this, select Calibration on the Options menu, then
choose either Front inlet or Back inlet, press [Enter], and turn Auto
flow zero on.
Auto zero septum purge
This is similar to Auto flow zero, but is for the septum purge flow.
Zero conditions
Flow sensors are zeroed with the carrier gas connected and
flowing.
Pressure sensors are zeroed with the supply gas line
disconnected from the gas control module.
Zero intervals
To zero a specific flow or pressure sensor
1 Press [Options], scroll to Calibration, and press [Enter].
2 Scroll to the module to be zeroed and press [Enter].
3 Scroll to a zero line and press [Info]. The GC will remind you
of the conditions necessary for zeroing that specific sensor.
Flow sensors. Verify that the gas is connected and flowing
(turned on).
Table 7 Flow and Pressure Sensor Zero Intervals
Sensor type Module type Zero interval
Flow All Use Auto flow zero and/or
Auto zero septum purge
Pressure Inlets
Packed columns Every 12 months
Small capillary columns
(id 0.32 mm or less)
Every 12 months
Large capillary columns
(id > 0.32 mm)
At 3 months, at 6 months,
then every 12 months
Auxiliary channels Every 12 months
Detector gases Every 12 months