High Voltage Power Supply; Pneumatic Sensor Assembly; Sample Pressure; Izs Option - Teledyne 100E Instruction Manual

Model 100E Instruction Manual

11.5.13. High Voltage Power Supply

The HVPS is located in the interior of the sensor module and is plugged into the PMT tube
(Figure 10-13). It requires 2 voltage inputs. The first is +15 which powers the supply.
The second is the programming voltage which is generated on the Preamp Board. This
power supply is unlike a traditional PMT HVPS. It is like having 10 independent power
supplies, one to each pin of the PMT. The test procedure below allows you to test each
supply.
Adjustment of the HVPS is covered in the factory calibration procedure in Section 11.6.3.

11.5.14. Pneumatic Sensor Assembly

The pressure/flow sensor circuit board, located behind the sensor assembly, can be
checked with a voltmeter using the following procedure, which assumes that the wiring is
intact and that the motherboard and the power supplies are operating properly.
Measure the voltage across TP1 and TP2, it should be 10.0 ± 0.25 V. If not, the board is
faulty. Measure the voltage across capacitor C2, it should be 5.0 ± 0.25 V. If not, the
board may be faulty.

11.5.14.1. Sample Pressure

Measure the voltage across test points TP1 and TP4. With the sample pump disconnected
or turned off, this voltage should be 4500 ± 250 mV. With the pump running, it should be
about 0.2 V less as the sample pressure drops by about 1 in-Hg-A from ambient
pressure. If this voltage is significantly different, the pressure transducer S2 or the board
may be faulty. A leak in the sample system to vacuum may also cause this voltage to be
between about 0.6 and 4.5. Make sure that the front panel reading of the sample
pressure is at about 1 in-Hg-A less than ambient pressure.

11.5.15. IZS Option

The zero/span valves and IZS options need to be enabled in the software (contact the
factory on how to do this). See Figure 5-2 and 5-3 for a flow diagram with zero/span
valve or IZS option.
• Check for the physical presence of the valves or the IZS option.
• Check that a working perm-tube is installed in the IZS oven assembly.
• Check front panel for correct software configuration. When the instrument is in
SAMPLE mode, the front panel display should show CALS and CALZ buttons in the
second line of the display. The presence of the buttons indicates that the option
has been enabled in software. In addition, the IZS option is enabled if the TEST
functions show a parameter named IZS TEMP.
The semi-permeable PTFE membrane of the permeation tube is affected by humidity. If
the instrument is installed in an air-conditioned shelter, the air is usually dry enough to
produce good results. If the instrument is installed in an environment with variable or
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