Instruction manual

Instruction Manual Smart-Trak
®
50 Series
IM-50 Rev. A.2 29
Over-Range Condition
If the mass flow rate exceeds the full scale range listed on the Smart-Trak
®
50 Series data
label the output signal will measure above full-scale. However, the device has not been
calibrated for flows in excess of the calibrated full scale value and the value will be both
non-linear and inaccurate if an over-range condition exists. Please be aware that the
analog outputs can exceed full scale by as much as 20%, or more.
Once the over-range condition has been removed, it may take up to 30 seconds for the 50
Series to recover and resume normal operation. An over-range condition will not
harm
the instrument.
IMPORTANT NOTES ABOUT PURGING
Purging Non-Reactive Gases:
Purge your 50 Series with clean, dry nitrogen for a minimum of two hours. To purge an
MFC apply a full scale setpoint.
Purging Reactive Gases:
One of the following methods may be used:
 Cycle purge. This is done by alternately evacuating and purging the instrument for 2
to 4 hours with clean, dry nitrogen.
 Purge the instrument with clean, dry nitrogen for 18 to 24 hours.
 Evacuate the instrument for 18 to 24 hours.
Important Safety Notes About Purging
WARNING! When toxic or corrosive gases are used, purge unit thoroughly with inert
dry gas before disconnecting from the gas line to prevent personnel from being injured
when coming in contact with the instrument. Above discusses how to purge your
instrument. Always neutralize any toxic gas trapped inside the instrument before removing
it from the gas line. If an instrument used with a toxic or corrosive gas is returned to the
factory a Material Safety Data Sheet (MSDS) must be enclosed & attached to the outside
of the box to alert Sierra personnel of the potential hazard. Also make sure the inlet &
outlet are securely sealed.