Teledyne T100, Instruction Manual, Page: 63 / 404

Teledyne ML - T100 UV Fluorescence SO2 Analyzer
Getting Started
63
Table 3-11 describes the operational state of the valves associated with the IZS option
during the analyzer’s various operating modes.
Table 3-11: IZS Valve Operating States
MODE VALVE CONDITION
SAMPLE
Sample/Cal Open to SAMPLE inlet
Zero/Span Open to ZERO AIR inlet
ZERO CAL
Sample/Cal Open to zero/span valve
Zero/Span Open to ZERO AIR inlet
SPAN CAL
Sample/Cal Open to zero/span valve
Zero/Span Open to SPAN GAS inlet
The state of the IZS valves can also be controlled by any of the following means:

Manually from the analyzer’s front panel by using the
SIGNAL I/O controls under the
DIAG Menu (refer to Section 4.8.2),

By activating the instrument’s AutoCal feature (refer to Section 6.8),

Remotely by using the external digital control inputs (refer to Section 5.3.1.2 and Section
6.7.1),

Remotely through the RS-232/485 serial I/O ports (refer to Appendix A-6 for the applicable
commands), or

Remotely via Ethernet
IMPORTANT The permeation tube is not included in the IZS Option and must be ordered separately.
Refer to Section 1.3 for permeation tube options.
3.5.4.1. 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.
The IZS option includes an external zero air scrubber assembly that removes all SO
2
the
zero air source. The scrubber is filled with activated charcoal.
3.5.4.2. SPAN GAS CONCENTRATION VARIATION
Span gas is created when zero air passes over a permeation tube containing liquid SO
2
under high pressure, which slowly permeates through a PTFE membrane into the
surrounding air. The speed at which the SO
2
permeates the membrane is called the
effusion rate. The concentration of the span gas is determined by three factors:

Size of the membrane: The larger the area of the membrane, the more permeation occurs.

Temperature of the SO
2
: Increasing the temperature of the increases the pressure inside the
tube and therefore increases the effusion rate.