Teledyne T101, Operation Manual, Page: 52 / 375

Getting Started Teledyne ML – T101 Operation Manual
48
Temperature of the H
2
S : Increasing the temperature of the increases the pressure inside
the tube and therefore increases the effusion rate.
Flow rate of the zero air : If the previous two variables are constant, the permeation rate
of the calibration gas into the zero air stream will be constant. Therefore, a lower flow
rate of zero air produces higher concentrations of H
2
S. The T101 usually has a constant
flow rate and a constant permeation rate; hence, variations in concentration can be
achieved by changing the IZS temperature.
NOTE
The permeation tube is not included in the IZS Option and must be ordered separately.
Permeation Tube Heater
In order to keep the permeation rate constant, the IZS enclosure is heated to a constant
50° C (10° above the maximum operating temperature of the instrument). The IZS heater
is controlled by a precise PID (Proportional/Integral/Derivative) temperature control loop.
A thermistor measures the actual temperature and reports it to the CPU for control
feedback.