Specifications

10-1
SRS Residual Gas Analyzer
Chapter 10
RGA Circuit Description
This chapter describes the electronics circuits located inside the Electronics Control Unit of
the RGA.
There are no electronics components inside the RGA Probe.
The information in this chapter is provided for the use by qualified technical personnel
during service and repairs.
Warnings
x The ECU is to be serviced by qualified technical personnel only. There are no
user serviceable parts inside.
x Dangerous voltages, capable of causing injury or death, are present in this
instrument. Use extreme caution whenever the ECU covers are removed. Do not
remove the covers while the unit is plugged in.
x Always disconnect the power before removing the covers of the ECU.
In This Chapter
Overview of the RGA ............................................................................................................................ 10-3
Circuit Description................................................................................................................................ 10-4
General Description.................................................................................................................. 10-4
Circuit Boards ........................................................................................................................... 10-5
Description of Schematics................................................................................................................... 10-6
Schematic name: QMSE_T1 .................................................................................................... 10-6
Microprocessor ....................................................................................................................... 10-6
Digital I/O Ports...................................................................................................................... 10-6
The LED port.......................................................................................................................... 10-7
The MPX port ......................................................................................................................... 10-7
The MISC port........................................................................................................................ 10-7
Clocks ..................................................................................................................................... 10-7
RS232 Interface ...................................................................................................................... 10-8
Schematic name: QMSE_T2 .................................................................................................... 10-8
I/V calibration......................................................................................................................... 10-8