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LEYBOLD INFICONIn Situ Analysis

Tech NoteTCA-485
A New Approach to a Platform
Independent RS-485 Controller
Residual Gas Analyzers (RGAs) havebeen used in vacuum research applications for 25 years. Their role
has changed in the last 10 years, as
they have moved from purely a research instrument to a production
tool. As a production tool, the RGA
can increase productivity, improve
product yield, increase throughput
and reduce costs, all of which ultimately increase profits.
However, it is up to the user to determine how the tool can best meet theneeds of a specific application. ThisTech Note is concerned with an independent RS-485 network platform for the operation of multiple
Transpector® RGAs.

How an RGA is Used
Manyproduction
vacuumsystems, especially those used withinsemiconductor equipment, are madeup of multiple chambers. These“cluster tools” utilize separate RGAs
for each of the chambers, typically
4-6 instruments, but it is impracticaland wasteful to have individual computers for each sensor. It is therefore
necessarytouseacommunications BUS, like RS-485,
to communicate at the same timewith all RGAs on the tool. RS-485
communications normally require aboard to be added to the controlling
PC. This limits the use of a laptop
computer to only one sensor at a time.
Additionally, some mainstream users
are switching from the Microsoft®
WindowsTM 95/98 operating system toMicrosoft NT, which will not operatewith 16 bit application software. TheTCA-485 is a new dependable anduniversal hardware solution that will
work with 32 bit applications softwareand not be restricted by the limitations of the controlling PC.

TCA-485 Hardware
The TCA-485 has two 9 pin D-Sub
connectors at each end. One connector will attach via a 9-pin female tofemale cable, to the desktop, or laptop RS-232 port. The other connector
on the TCA-485 will connect directly
to the RS-485 cable on the Transpector. Figure 1 shows a typical set ofsystem connections. The TCA-485 isRS-485
CablesWindows 95/98 or NT
PC RS-232 PortorTCA-485
Windows 95/98 or NT
Laptop RS-232 Port

RGAs

Figure 1: TCA-485 System
Configuration

powered by an external 12 volt power
supply. This power source is a wallmountable transformer type. A picture of the new RS-232 to RS-485
converter is shown in Figure 2.

Figure 2: TCA-485

TCA-485 Requirements andUse
Once all the connections have been
made the communications are seamless. The only other requirements arethat the computer must be operatingon Windows 95 and later or Windows
NT 4.0 and later. The user must also
be running TWare 32, version 1.0 or
later to control the Transpector RGAs.
Additionally, the TCA-485 can be usedwith an Inficon 32 bit DDE Driver (Dynamic Data Exchange). The TCA-485
will not operate with TranspectorWareTM
software.

The Advantages of the TCA-485•Hardware multiplexing solution that minimizes CPU time•

Independent of PC interrupts, addresses and other hardware issues•

Multiplexing capability with notebook and laptop computers•

No computer slots required•

No computer disassembly required for board installation

TCA-485 Specifications
Power requirement

12 v DC, +/- 30% @ 1 watt

Power input

External transformer (supplied)

Baud range (KB)

460.8, 230.4, 115.2, 76.8, 57.6, 38.4,19.2, 9.6

Default baud rate

57.6 KB

Indicators

Two green LEDs (Power and Transmit)

Multiplexing capability

Up to 31 Transpectors

Cable length

Maximum 1200 foot (~360 meters)

PC communications requiredStandard RS-232 serial communications port

Transpector communications required

RS-485 cables daisy chained as normal

Transpector is a registered trademark of Leybold Inficon.
TranspectorWare is a trademark of Leybold Inficon.
Microsoft is a registered trademark of Microsoft Corporation.
Windows is a trademark of Microsoft Corporation.

LEYBOLD INFICON
Two Technology Place
East Syracuse, NY 13057 USA
Tel (315) 434-1100
Fax (315) 437-3803
reachus@inficon.com
TN2731Y9PDF

TMP.O. Box 1000
FL-9496 Balzers, LiechtensteinTel +41 (0) 75 388 4382
Fax +41 (0) 75 388 5429
reachfl@inficon.com

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Tel +49 (0) 221 347 1999
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reachld@inficon.com© 1999 Leybold Inficon Inc.
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